The term typically refers to fuel that has been processed from petroleum, but increasingly, alternatives such as biodiesel or biomass to liquid BTL or gas to liquid GTL diesel that are not derived from petroleum are being developed and adopted. Distillation is a method of separating chemical substances based on differences in their volatilities. Distillation usually forms part of a larger chemical process, and is thus referred to as a unit operation. Esters are organic compounds in which an organic group symbolized by R' in this article replaces a hydrogen atom or more than one in a hydroxyl group.
Flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture in air. At this temperature the vapor may cease to burn when the source of ignition is removed. A slightly higher temperature, the fire point, is defined as the temperature at which the vapor continues to burn after being ignited.
Glycerol, also well known as glycerin and glycerine, and less commonly as propane-1,2,3-triol, 1,2,3-propanetriol, 1,2,3-trihydroxypropane, glyceritol, and glycyl alcohol is a colorless, odorless, hygroscopic, and sweet-tasting viscous liquid. Glycerol is a sugar alcohol and has three hydrophilic alcoholic hydroxyl groups OH- that are responsible for its solubility in water.
Glycerol has a wide range of applications. Glycerol has a prochiral spatial arrangement of atoms. Methanol, also known as methyl alcohol, carbinol, wood alcohol or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colorless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol ethyl alcohol. It is used as an antifreeze, solvent, fuel, and as a denaturant for ethyl alcohol.
Transesterification is the process of exchanging the alkoxy group of an ester compound by another alcohol. These reactions are often catalyzed by the addition of an acid or base. Vegetable fats and oils are substances derived from plants that are composed of triglycerides.
Nominally, oils are liquid at room temperature, and fats are solid; a dense brittle fat is called a wax. Although many different parts of plants may yield oil, in actual commercial practice oil is extracted primarily from the seeds of oilseed plants. Viscosity is a measure of the resistance of a fluid to deform under shear stress. It is commonly perceived as "thickness", or resistance to flow. Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction.
In relation to the problem statement whereas, the rising cost of diesel fuels in the world market, the negative result of greenhouse gasses emissions in the environment and the bad effects to our health - this report provide information with better understanding of what biodiesel is, the process of how it is produces as well as the equipments used; the public policy currently approved; the importance of using biodiesel as an alternative; the advantage and disadvantages of using biodiesel, the economic benefits.
An energy that is more practical to use in the same way that it is safer, renewable, available and of course - affordable. Biodiesel is one of the candidates of this needed energy because of its abundance and potential source in the country.
Biodiesel is a clean-burning diesel replacement fuel that can be used in compression-ignition CI engines, and which is manufactured from the following renewable, non-petroleum-based sources:. Virgin vegetable oils such as soy, mustard, canola, rapeseed and palm oils; Animal fats such as poultry offal, tallow, and fish oils; and Used cooking oils and trap grease from restaurants.
The level of care needed depends on the engine and vehicle manufacturer. Biodiesel is generally made when fats and oils are chemically reacted with an alcohol, typically methanol, and a catalyst, typically sodium or potassium hydroxide i. Rudolf Diesel, the inventor of the first compression-ignition CI engine, once said that "the use of vegetable oils for engine fuels may seem insignificant today but such oils may become, in the course of time, as important as petroleum and the coal-tar products of the present time.
The discovery of transesterification of vegetable oil in by scientists E. Duffy and J. Patrick gave way to the invention of biodiesel fuel. Rudolf Diesel's prime model, a single 10 ft 3 m iron cylinder with a flywheel at its base, ran on its own power for the first time in Augsburg, Germany on August 10, In remembrance of this event, August 10 has been declared "International Biodiesel Day". This engine stood as an example of Diesel's vision because it was powered by peanut oil — a biofuel, though not biodiesel, since it was not transesterified.
He believed that the utilization of biomass fuel was the real future of his engine. In , more than a century later after the discovery of the first transesterification of vegetable oil, South Africa initiated the use of trans- esterified sunflower oil, and refined it to diesel fuel standards, By the process for producing fuel-quality, engine-tested biodiesel was completed and published internationally. An Austrian company, Gaskoks, obtained the technology from the South African Agricultural Engineers; the company erected the first biodiesel pilot plant in November , and the first industrial-scale plant in April with a capacity of 30, tons of rapeseed per annum.
Throughout the s, plants were opened in many European countries, including the Czech Republic, Germany and Sweden. During the same period, nations in other parts of world also saw local production of biodiesel starting up: by the Austrian Biofuels Institute had identified 21 countries with commercial biodiesel projects. In September of Minnesota became the first U. In Asia, Chemrez Technologies Inc. Chemrez Technolologies Inc.
The process used to convert these oils to Biodiesel is called transesterification. There are two basic routes to biodiesel production from oils and fats:. Most of the biodiesel produced today is done with the base catalyzed reaction for several reasons:. It is low temperature and pressure. It is a direct conversion to biodiesel with no intermediate compounds. No exotic materials of construction are needed. For this reason only this process will be described. A triglyceride has a glycerine molecule as its base with three long chain fatty acids attached.
During the esterification process, the triglyceride is reacted with alcohol in the presence of a catalyst, usually a strong alkaline like sodium hydroxide. The alcohol reacts with the fatty acids to form the mono-alkyl ester, or biodiesel and crude glycerol.
In most production methanol or ethanol is the alcohol used methanol produces methyl esters, ethanol produces ethyl esters and is base catalyzed by either potassium or sodium hydroxide. Vegetable oils, animal fats, and recycled greases.
These materials contain triglycerides, free fatty acids, and other contaminants depending on the degree of pretreatment they have received prior to delivery. The most commonly used primary alcohol used in biodiesel production is methanol, although other alcohols, such as ethanol can also be used. A key quality factor for the primary alcohol is the water content. Water interferes with transesterification reactions and can result in poor yields and high levels of soap, free fatty acids, and triglycerides in the final fuel.
Ethanol is 3. In addition, a base catalyzed process typically uses an operating mole ratio of mole of Alcohol rather than the ratio required by the reaction. The unused alcohol must be recovered and recycled back into the process to minimize operating costs and environmental impacts. Methanol is considerably easier to recover than the ethanol.
Ethanol forms an azeotrope with water so it is expensive to purify the ethanol during recovery. If the water is not removed it will interfere with the reactions. Most processes for making biodiesel use a catalyst to initiate the esterification reaction. The catalyst is required because the alcohol is sparingly soluble in the oil phase. The catalyst promotes an increase in solubility to allow the reaction to proceed at a reasonable rate.
Base catalysts are used for essentially all vegetable oil processing plants essentially all of the current commercial biodiesel producers use base catalyzed reactions. Base catalyzed reactions are relatively fast, with residence times from about 5 minutes to about 1 hour, depending on temperature, concentration, mixing and alcohol:triglyceride ratio.
Neutralizers are used to remove the base or acid catalyst from the product biodiesel and glycerol. If you are using a base catalyst, the neutralizer is typically an acid, and visa versa. If the biodiesel is being washed, the neutralizer can be added to the wash water. While hydrochloric acid is a common choice to neutralize base catalyst.
The catalyst is typically sodium hydroxide caustic soda. It is dissolved in the methyl alcohol using a standard agitator or mixer. The system from here on is totally closed to the atmosphere to prevent the loss of alcohol. Excess alcohol is normally used to ensure total conversion of the fat or oil to its esters. Care must be taken to monitor the amount of water and free fatty acids in the incoming oil or fat. If the free fatty acid level or water level is too high it may cause problems with soap formation and the separation of the glycerin by-product downstream.
A popular variation of the batch process is the use of continuous stirred tank reactors CSTRs in series. An essential element in the design of a CSTR is sufficient mixing input to ensure that the composition throughout the reactor is essentially constant. The reactor is the only place in the process where chemical conversion occurs. Continuous reactors have a steady flow of reactants into the reactor and products out of the reactor.
Once a continuous flow reactor reaches steady state operation, the product composition leaving the reactor becomes constant. For CSTRs, the reactants are fed into a well-mixed reactor. The composition of the product stream is identical to the composition within the reactor. Hold-up time in a CSTR is given by a residence time distribution. The residence time is defined by the length of time required for molecules to travel through the reactor.
The most important considerations within a reactor are the extent of reaction of the reactants, which is known as conversion key reactor variables that dictate conversion are temperature, pressure, reaction time residence time , and degree of mixing. In general, increasing the reaction temperature increases the reaction rate and, hence, the conversion for a given reaction time.
The obtained solid was then extracted with diethyl ether and dichloromethane mixture for 6 h and was dissolved in a tetramethylammonium hydroxide solution in methanol. The solution was stirred at room temperature for 4 h, through which the chloride anions were exchanged to hydroxides. Employing this heterogeneous catalyst resulted in the conversion of The catalytic activity of basic ILs strongly depends on basicity. However, it should be noted that excessive loading of IL on the support results in decreased catalytic activity, as it reduces the specific surface area.
Therefore, the amount of grafted IL on the support should be optimized. As an example, in another work by Xie et al. In the first step, DCOG and 1,3-glycidyloxypropyl-trimethoxysilane were added to dry N,N-dimethylformamide and the mixture was stirred at room temperature for 48 h under N 2 atmosphere to yield DCOG-organosilane.
Afterwards, SBA was dispersed in dry toluene and refluxed for 2 h with stirring under N 2 atmosphere. The resultant mixture was refluxed with stirring in the N 2 atmosphere for 24 h. By using 8 wt. The catalytic activity increased when the loading amount of IL was lower than 2. The inclusion of organic functional into the structure of inorganic mesoporous silica materials leads to the formation of mesoporous organosilicas.
These organic-inorganic hybrid mesoporous materials compensate the drawbacks of both siliceous mesoporous supports, i. One problem associated with the use of SBAsupported ILs in the esterification reaction is the leaching of ILs from the surface of the support, which limits catalyst recoverability and reusability.
Elhamifar et al. After the preparation of PMO-IL, it was modified through grafting of 3-mercaptopropyl trimethoxysilane. To this end, PMO-IL was added to dry toluene at room temperature under stirring for 5 min 3-mercaptopropyl trimethoxysilane was then added to the solution and the mixture was refluxed under the argon atmosphere for 24 h. Afterwards, a dilute solution of sulfuric acid was added to the mixture under stirring for 30 min.
The high efficiency was ascribed to the presence of imidazolium anion and sulfonic acid groups in the mesochannels of the carrier and their synergetic cooperation. They also stated that the nanostructure of PMO-IL with the imidazolium framework was responsible for the good stability of sulfonic acid sites.
Fan et al. Acidic IL sulfonic acid functionalized imidazolium hydrogen sulfate [Ps-im] HSO 4 was then immobilized on the acidic organosilica carrier by the chemical grafting. Figure 2 illustrates the four steps involved in the production process of the catalyst. In the next step, this product was dispersed in dry toluene and 1,3-propane sultone was added to the mixture.
The mixture was then stirred at room temperature for 24 h. This catalyst was used to produce biodiesel from soybean oil, where under optimum reaction conditions of 5 wt. Despite having lower acidity, the catalyst gave a higher yield as compared with the pure [Ps-im] HSO 4 owing to the synergetic impact of Bronsted and Lewis acid sites.
The catalyst maintained its activity after 5 consecutive runs and exhibited excellent resistance to oleic acid and water. Figure 2. Magnetic mesoporous silica is one of the most important classes of mesoporous materials that have been used as carriers for ILs. Magnetic mesoporous materials can combine the benefits of mesoporous and magnetic materials, and facilitate the separation of the catalyst from reaction mixture through a magnetic field.
Figure 3 illustrates the process for the synthesis of this catalyst. The magnetic carrier was synthesized by embedding the cobalt ferrite nanoparticles in silica using the sol-gel method and then modified with 3-mercaptopropyl trimethoxysilane to add sulfhydryl groups to its structure. The IL was then supported on the modified magnetic mesoporous silica through a radical reaction between the allyl and sulfhydryl groups. They found that an increase in sulfhydryl loading of modified mesoporous silica resulted in a decrease in pore diameter, the amount of IL supported on the carrier, and conversion.
Figure 3. The catalytic performance of mesoporous silica-based ILs could be even better than that of the ILs supported on nanoparticles. The modified SCF particles were washed with acetone and dried. In the next step, IL was supported on the carrier through the free radical reaction between allyl groups of IL and sulfhydryl groups of the carrier.
The mesoporous structure of SCF made it difficult for the large molecule of triglyceride to diffuse into the pores and reach the active sites of IL, so the reaction rate and yield were low at the beginning of the reaction.
However, the long and narrow pores also prevented the triglyceride and intermediate diglyceride to escape from the surface of the carrier, thus providing longer contact opportunities for reactants and intermediate with catalytic sites. Wan et al. The Fe 3 O 4 nanoparticles were produced by the solvothermal method. Then, they were coated with silica layer through hydrolysis and condensation of tetraethyl orthosilicate in the mixture of water, ethanol and ammonia, producing Fe 3 O 4 SiO 2 particles.
Afterwards, these particles were coated with a composite layer consist of cetyltrimethylammonium bromide CTAB and silica by using tetraethyl orthosilicate and CTAB. In the next step, the IL was supported on the mesoporous silica by covalent immobilization, with Fe 3 O 4 and mesoporous silica-based IL as core and shell, respectively. Typically, a mixture of IL and mesoporous carrier in dry toluene was prepared. The mixture was refluxed for 24 h under N 2 atmosphere. In this catalyst, the function of non-porous inner silica layer was to protect the Fe 3 O 4 nanoparticles, while the outer mesoporous layer acted as support.
At optimum reaction conditions of Based on the above discussion, there are two main methods for supporting ILs on silicon-based materials: Impregnation and grafting. Impregnation consists of physical adsorption of the IL, whereas in grafting the IL is immobilized on the surface through a chemical bond. Impregnation is simpler and less expensive than chemical grafting, but the resultant catalyst does not usually show good stability because the active sites are fallen off the surface of the support.
In contrast, chemical grafting results in catalysts with higher stabilities, but it is more complicated and time-consuming, as well as consumes extra chemicals and reagents which increases the fabrication cost. These bonds are formed by a chemical reaction between the silane groups and silanol groups on the carrier surface. There are two ways to incorporate silane groups in the structure of final catalyst.
In the first method, which we call carrier modification, the as-synthesized carrier is functionalized with silane groups. Then, IL is connected to the silanol group through another group such as propyl or thiol. In the second method, called direct immobilization, the silane groups are first incorporated in IL structure, and then the IL is directly immobilized on the support.
As can be seen, all studies synthesized catalysts with large specific surface areas and obtained high biodiesel yields. Except for researches conducted by Karimi and Vafaeezadeh and Zhang et al. Although Karimi and Vafaeezadeh did not report the biodiesel yield after several catalytic cycles, the results reported by Zhang et al. As impregnation is simpler and less-expensive than grafting, further studies on using this synthesis method with critical attention on recyclability are worth conducting in the future.
The high specific surface area of microporous silica-gel led to a comparable biodiesel yield with mesoporous silica supports. However, a higher amount of alcohol and longer reaction time was required which can be attributed to the smaller pore diameter of silica-gel and limited diffusion of the reactants as a result.
These problems may be overcome by employing basic ILs which accompany lower alcohol consumption and shorter reaction time compared to acidic ILs. The effect of direct immobilization of IL on the recyclability of the final catalyst can also be investigated in future research. Most studies in this category have been focused on SBA By comparing the results, one could conclude that the modification of carrier with thiol groups Wang et al.
When the carrier is modified through thiol-ene reaction, the silane group on the surface is first attached to one atom of S through a propyl group. Then, this atom is connected to the cation of IL via another propyl group. In direct immobilization, on the other hand, the IL is directly attached to the silane group through a propyl group. Moreover, when the water and oleic acid contents of the feedstock were 5 wt.
These results indicate that mesoporous organosilica materials have great potential in trans esterification. Despite that Fan et al. Finally, in all three studies on magnetic mesoporous silica supports, high yields were reported. However, the catalysts fabricated by Zhen et al.
In both studies, the support was first functionalized with thiol groups and then IL was attached to the support via free radical addition reaction between allyl groups of the IL and thiol groups on the surface of the carrier. On the contrary, Wan et al. In summary, direct immobilization of IL on the surface of mesoporous silica carrier through silane groups seems to reduce the leaching of IL and improve the catalyst recyclability compared to the case where thiol groups are used.
Organic polymers containing nanopores possess controlled wettability, flexible chemical tenability, and remarkable chemical stability in addition to the high surface area. Generally, these materials can be easily fabricated through hard-templating, soft-templating and template-free methods, and are functionalized by several strategies such as post-modification, co-polymerization of skeleton molecules with functional groups and self-polymerization of functional organic groups Sun et al.
The functionalization of nanoporous polymers with ILs leads to the fabrication of so-called polymeric or polymerized ionic liquids or poly ionic liquids s PILs. These polyelectrolytes consist of a polymeric backbone and an IL species in each monomer repeating units. PILs have been widely used as catalyst, catalyst support and pre-catalyst as they are mechanically stable and their catalytic influence can be controlled by the possibility of choosing a variety of cations and anions and tuning the macromolecular structure Qian et al.
There are two principal strategies to fabricate PILs, i. The structure, merits, and shortcomings of a PIL strongly depend on the synthesis technique and polymerization methodology Yuan and Antonietti, In the post-modification route, an existing precursor polymer is functionalized via chemical reactions.
PILs obtained from this strategy possess the same number of monomeric units, architecture, and monomer composition as the primary polymer chains. Consequently, the desirable architecture and composition of PILs can be achieved by choosing a precursor with suitable structure, mass, and architecture Yuan and Antonietti, The modification of nanoporous polymers for the preparation of PIL catalysts and their use in the biodiesel production process was first reported by Liu F. They synthesized several mesoporous superhydrophobic polydivinylbenzenes by solvothermal co-polymerization of divinylbenzene with a series of vinyl-based monomers, followed by quaternary ammonization with CH 3 I and ion exchange with HSO 3 CF 3.
Compared to the same homogeneous ILs and ILs supported on SBA and Amberlyst 15, the obtained IL-functionalized mesoporous polymers gave higher palmitate yield in transesterification of tripalmitin. This was attributed to the excellent adsorption of the reactants on the catalyst as a result of its significant wettability for the reactants. The catalyst was also well-recyclable because of the stable polymer structure. However, very high alcohol to tripalmitin molar ratio 90—1 and long reaction time 16 h were required to achieve high yields.
Templating is an effective method for the synthesis of nanoporous polymers. Noshadi et al. The crosslinker hexamethylenetetramine HMTA was used to link the precursor to the template. Due to high acidity, high specific surface area, and a stable hydrophobic polymeric structure, this catalyst outperformed HCl and Amberlyst 15 in the esterification of a brown grease feed with high FFA content.
The conversion of FFA to biodiesel reached The yield of esterification decreased from However, due to the need for high volumes of alcohol the methanol-to-feed molar ratio of 40—1 and moderate yield, this catalyst is not suitable for the transesterification reaction presumably due to its small pores that do not provide adequate space for the diffusion of larger triglyceride molecules.
Adding sulfonic groups to a polymer functionalized with an acidic ionic liquid IL may significantly improve both acidity and catalytic activity. After synthesizing a mesoporous polymer through copolymerization of divinylbenzene with 1-vinylimidazole, Pan et al. The resulting acidic PIL was sulfonated with chlorosulfonic acid to add a sulfonic acid group to the monomer. Despite the lower acidity of this catalyst than Amberlyst 15, its BET surface area was 5 times higher leading to a significant increase in the conversion.
One limitation of some PILs used in biodiesel production is their nano-scale particles causing loss of catalyst during separation from reaction products. Increasing the particle size to micro-scale facilitates catalyst separation and reduces relevant costs. Using the procedure shown in Figure 4 , Feng et al. The resulting catalyst, P VB-VS HSO 4 , had an oleophilic mesoporous polymer network with a high specific surface area and abundant mesopores leading to the increased contact area of reactants with active sites and thereby enhanced mass transfer.
Interestingly, catalyst loss was nearly zero during recovery and reuse due to micron-sized catalyst particles. Moreover, the resulting PIL led to a high biodiesel production yield from various feeds with high acid values.
Figure 4. It has been reported that post-modification of the mesoporous melamine-formaldehyde as a class of covalent organic polymers COPs with ILs creates an ideal PIL for catalyzing esterification reactions. The repeating units in the mesoporous melamine-formaldehyde are connected through irreversible covalent bonds leading to high chemical and hydrothermal stability.
Since this polymer is synthesized from low-cost available monomers, i. As another advantage, many aminal groups and triazine rings in the polymer network provide abundant sites for functionalization. Pan et al. Strong covalent bonds between the polymer and IL as well as the stable structure of the catalyst led to its acceptable activity after 4 times of reuse.
There has been recently a great interest in the use of cheap monomers to reduce PIL production costs. For instance, Pei et al. The resulting polymer was first functionalized by allyl chloride and then imidazole and ultimately modified through reaction with 1,3-propanesultone and anion exchange with 1,3-p-toluenesulfonic acid to achieve the PIL [HCPpitch—Im—Pros][Tos].
Since the chlorine ions are replaced with imidazole groups in this method, the number of functional groups in the polymer increases with further chlorine grafting on the polymer leading to an increase in catalytic activity. Direct copolymerization of divinylbenzene with IL monomers is a less expensive process for the synthesis of PILs which eliminates the use of expensive coupling reagents.
Polydivinylbenzene can enhance the mass transfer rate and prevent the acid sites from falling off the surface owing to its high hydrophobic BET surface area. The obtained monomer then was successfully copolymerized with divinylbenzene and was used in transesterification of waste cooking oil with methanol. After 12 h, a Figure 5. Some PILs have a small specific surface area leading to inadequate access of reactants to catalytic sites. Hard templating of nanoparticles can be used to overcome this problem, which is a facile and effective method for producing porous materials with a suitable pore structure.
However, a suitable template is required for this purpose to generate a uniform pore structure and its facile removal from the polymer at the end of the process. Wu et al. To this end, Fe 3 O 4 nanoparticles were first modified with 3-methacryloxypropyltrimethoxy-silane and then polymerized with the IL monomer 1-vinyl 3-sulfopropyl imidazolium hydrogen sulfate. The resulting PIL contained a large number of sulfonic acid and hydrogen sulfate groups.
The PIL was reused up to 6 times without leaching its acidic sites. In another study, Wu et al. To functionalize Fe 3 O 4 nanoparticles with vinyl groups, 3- trimethoxysilyl propyl methacrylate was used. Due to good magnetic properties, the catalyst was easily separated from products and reused for 6 times.
In addition to hydrophobicity, tunable wetting of catalyst for both reactants and products is of great importance, as it improves the performance and recoverability of the catalyst. A basic PIL was synthesized through radical polymerization of 1-octylvinylimidazolium bromide with the crosslinker 1,4-butanediylbisvinylimidazole and then anion exchange with KOH Jiang et al.
The resulting polymer contained mesopores with an average diameter of 35 nm and basicity of 3. The rough surface of this polymer with a unique porous structure, an organic hydrophobic framework, and long chains of IL monomers led to a superhydrophobic polymer. Moreover, the high affinity of this catalyst for methanol and soybean oil led to the high yield of transesterification reaction.
On the other hand, the basic PIL was incompatible with glycerol leading to desorption of the byproduct, glycerol, from the catalyst surface. The catalyst resisted against a water content of up to 1. However, due to the lack of metal ions in the PIL structure, it does not cause environmental pollution unlike CaO. The free radical polymerization between an IL monomer and divinylbenzene in the presence of the radical initiator azobisisobutyronitrile AIBN is a common method for the synthesis of PILs.
Bian et al. The IL monomer was synthesized through the reaction of methyldiallylamine with 1,3-propanesulton and then ion exchange with trifluoromethanesulfonic acid. Despite the lower acidity of the resulting catalyst than Amberlyst 15, it led to a higher yield for methyl oleate production due to the higher surface area of the PIL The resulting PIL also had a reasonable recovery and reuse capacity.
The results of research on biodiesel production over PILs are summarized in Table 2. The post-modification method was used in the first six studies Liu F. This method is based on three consecutive steps including polymer synthesis, modification through quaternary ammonization, and ion exchange. Among the aforementioned studies, Liu F. However, this result was accompanied by the highest alcohol consumption and the longest reaction time in this category, which is probably due to the lack of catalytic sites on the imidazolium cation.
This speculation is confirmed by investigating the results of the next studies, in which more moderate reaction conditions were obtained by attaching a sulfonic acid group to the cations of PILs. When more acid sites are available for reactants, the reaction rate is increased and less alcohol is consumed.
In the next five studies Liang, a ; Wu et al. Among this group, Liang a reported the best results in the transesterification of waste cooking oil. The only basic PIL in this group was fabricated by Jiang et al. However, given to its basic nature, lower alcohol consumption and shorter reaction time are expected compared to the acidic PILs, which is not observed.
This may be due to the presence of octyl groups on the imidazolium cation of PIL and its complex cross-linker. Although incorporating these groups enhances hydrophobicity and expels glycerol from the surface of the catalyst, it limits the diffusion of reactants toward the active sites. Among all studies focused on PILs, Bian et al.
From what mentioned earlier, it can be concluded that both post-modification and direct polymerization could result in highly active PIL catalysts for trans esterification. Nevertheless, given the low price of divinylbenzene, using a template-free method could reduce the fabrication cost of final polymer compared to the templating technique.
Furthermore, direct polymerization is less complicated than the post-modification method, so the synthesis cost of PILs could be reduced by direct polymerization of IL monomer with the cheap divinylbenzene as co-polymer. In addition to the direct use of PILs as esterification and transesterification catalysts, the immobilization of these materials on nanoporous supports has also been studied.
For example, palygorskite is a mineral with a nanofiber-like structure containing aluminum and hydrated magnesium. High specific surface area, high thermal and mechanical stability, and abundant silanol units on the surface have turned this substance good support. Moreover, this substance is abundant in nature and sufficient hydroxyl groups can be created by acid activation to increase its grafting density. Zhang W. In the synthesis of this PIL, the weight ratio of the IL to palygorskite, temperature, reaction time and AIBN level affect the amount of ionic liquid immobilized on the support and thus should be optimized.
This significant reduction in reaction yield was attributed to the dissolution of IL in methanol and its reduced loading on the support, adhesion of esters on the support and reduced specific surface area and active sites and catalyst loss in the recovery process. Later, the palygorskite-supported PIL was used for the preparation of a hybrid organic-inorganic pervaporation catalytic membrane.
In addition to the catalytic effect, these membranes increase the efficiency of equilibrium reactions by removing one of the products from the reaction medium. The membrane was prepared by mixing poly vinyl alcohol with the PIL supported on palygorskite and succinic acid was used to link Poly vinyl alcohol through crosslink reaction. Adding a solid catalyst to poly vinyl alcohol improved thermal and mechanical stability and hydrophobicity of the PIL.
Another class of supports used for immobilizing PILs is nanoporous magnetic silica that facilitates PIL separation from the reaction mixture by an external magnetic field. Zhang H. Figure 6 shows the fabrication route to this catalyst. To prepare the support, Fe 3 O 4 nanoparticles were first prepared by the solvothermal method and then coated with SiO 2 by the sol-gel method to obtain Fe 3 O 4 SiO 2 microspheres. Thereafter, the external layer of the mesoporous silica was formed on the support by adding tetraethyl orthosilicate, P, and HCl.
The resulting magnetic mesoporous support was functionalized with sulfhydryl groups after reaction with 3-mercaptopropyl trimethoxysilane. Eventually, the hydroxide ions replaced bromide ions through ion exchange with tetramethylammonium hydroxide to obtain the basic Fnms-PIL catalyst. In addition to a high surface area, the density of basic sites was high and grafting of organic functional groups did not negatively affect the mesoporous structure.
The yield of transesterification reaction of the non-edible vegetable oil in the presence of this catalyst under mild reaction conditions including a methanol-to-oil molar ratio of , a catalyst concentration of 4 wt. Figure 6. As mentioned above, water as an esterification product negatively affects the catalytic activity and causes leaching of active sites. In another study, Zhang et al. An increase in the length of alkyl groups used for functionalizing the support improved its hydrophobicity.
The catalyst showed a good performance in converting oleic acid and Euphorbia lathyris L with a high acid number. Fe 3 O 4 nanoparticles are coated by a silica layer primarily for two reasons. First, magnetic nanoparticles are aggregated and form large clusters due to the bipolar-bipolar magnetic property. This in turn causes the non-uniform distribution of the catalyst in the reaction mixture and thereby reduced catalytic activity.
Second, the silica layer prevents corrosion of iron oxide nanoparticles under harsh conditions. The resulting hybrid organic-inorganic catalyst successfully converted The conversion of the oil to biodiesel was lower in the presence of the unsupported homopolymer. Given the same number of acidic sits, this was related to the lower surface area in this case.
To summarize the above discussion, the supported PILs are synthesized by copolymerization of the IL monomer and carrier, and Si-O-Si bonds are used to attach the cation of IL to the surface of mesoporous silica. To connect the cations to Si atoms, various chemical groups such as vinyl, propyl, and thiol have been employed. Table 3 compiles the results of previous research on biodiesel production over mesoporous silica-supported PILs.
Overall, excluding the results found by Zhang W. In both studies conducted by Zhang W. In each unit of the resultant catalyst, the imidazolium cation is attached to one Si atom through a long chain containing propyl and vinyl groups. Therefore, the stability of active sites should be improved, for which the IL can be attached to palygorskite through silane or thiol groups.
On the other hand, the very low yield was obtained by Li et al. This resulted from the limited number of active sites and negligible specific surface area of the catalyst. Moreover, polyvinyl alcohol may cover these active sites and limit the diffusion of the reactants. Therefore, increasing the specific surface area and PIL loading will be the main challenge in future studies.
The sole basic PIL in this group was synthesized and supported on magnetic mesoporous silica by Zhang H. They used thiol groups to attach the imidazolium cation of PIL to the carrier which led to a high biodiesel yield and good stability. The same method was employed for immobilizing an imidazolium-based acidic PIL on magnetic mesoporous silica and satisfactory results were obtained Zhang et al. These results demonstrate the good performance of the thiol-ene reaction for supporting PILs on silica materials.
Finally, vinyl groups were employed by Xie and Wang for the immobilization of an acidic PIL on a magnetic mesoporous silica carrier. The strong covalent bonds were responsible for the reasonable recyclability and high biodiesel yield in the transesterification of soybean oil. Therefore, incorporation of vinyl groups can result in high stability catalysts. Metal-organic frameworks MOFs are crystalline nanoporous materials that are obtained by combining inorganic nodes including metal ions or clusters of metal ions and organic ligands.
Depending on the type of metal ions and organic linkers and direction of linkages between ions, many MOFs with a variety of framework geometries can be designed. These structures contain voids or pores that their size, shape, and functionalization can be well-controlled unlike zeolites. Therefore, these pores can be used to confine the desired molecules Safaei et al. MOFs have recently played a key role in heterogenizing ILs to be used in various areas including gas adsorption, catalysis, and fabrication of nanoporous carbon.
In addition to a large number of nanopores in their crystalline structure, their properties such as pore size, surface area, framework topology, and polarity of the inner surface are tunable Fujie and Kitagawa, MOFs are very similar to ILs in this regard.
As properties of ILs are determined by cations and anions used in their structures, properties of MOFs can be designed by using various metal ions and organic ligands. In general, there are two methods for incorporation of ILs in the structure of MOFs: ionothermal synthesis and post-synthetic modification. As a solvothermal method, an IL is used as a solvent in the ionothermal method, and IL cations are attached to negatively charged MOF frameworks. Given the strong interaction of cations and the MOF framework, the useful properties are limited in comparison with the bulk IL.
As a result, the need for compatibility of ILs and MOFs is eliminated to a large extent and a wide range of both materials can be used Cota and Martinez, Accordingly, the post-synthesis method has been used in all studies on the application of hybrid IL-MOF catalysts for biodiesel production. For the first time, Wan et al. To this end, POM-MIL was added to the IL-methanol solution and the resulting mixture was vigorously stirred for 10 min and then treated with ultrasound waves for 30 min. The mixture was stirred for another 12 h at room temperature.
The catalyst was recovered 6 times and reused without any significant reduction in the conversion. In , Han et al. In this method known as the impregnation-reaction-encapsulation process, small molecules of the IL diffused into nanopores of the MOF and began to grow in the nanopores up to a point that was no longer able to escape from the MOF cages due to their large size. The magnetic support functionalized with amino groups was obtained through thermal treatment of 2-aminoterephthalic acid, FeCl 3.
A conversion of Using this method, Han et al. Figure 7 shows the procedure for the synthesis of this catalyst. The results showed that immobilization of the acidic IL on MIL Cr through S-Cr coordination bonds not only increased the oleic acid conversion but also improved catalyst reusability as compared with the neat MOF. Figure 7. Strong interactions between sulfonic acid groups and heteropoly tungstate molecules effectively prevented the loss of active species from the MOF support and led to reasonable stability of the catalyst during multiple recoveries and reuse cycles.
The catalyst showed higher activity in FFA esterification than the transesterification of soybean oil. Ye et al. In the so-called approximate ligand substitution method, parts of ligands were eliminated through MOF etching by propionic acid to produce the hierarchical porous UiO with a large number of defects and Lewis acid sites.
This catalyst showed higher activity in the esterification of oleic acid UiO also showed a catalytic activity due to defects and unsaturated Zr atoms in its natural structure leading to the opening of Lewis acid sites. However, these Lewis acids are not well accessible due to the lower diameter of pore aperture than the oleic acid molecule.
Using the tandem post-synthetic modification method, ILs with ions larger than the aperture diameter of the pores can be incorporated into MOF pores Fujie and Kitagawa, In this method, active species are grafted through coordination covalent bonds with UMCs. Chen et al. The mixture was stirred for 24 h at room temperature and the resulting suspension was centrifuged. The resulting solid was washed with ethanol and then dried under vacuum at room temperature.
The product was separated by filtration and then was washed several times with ethanol to remove excess IL. The catalyst was synthesized through covalent bonding of the vinyl groups of the IL with thiol groups in the HKUST-1 structure to achieve a conversion of The conversion reduced to H 2 O solution in ethanol.
The basic catalyst led to a conversion of The catalyst was used 5 times without a significant reduction in the conversion. Table 4 presents the results of previous studies on trans esterification of various feedstock over MOF-supported ILs. The results suggest that encapsulation leads to catalysts with better recyclability higher yield after multiple reuses compared to surface immobilization. On the other hand, a higher amount of catalyst is required for high biodiesel yields when encapsulation is employed.
This can be attributed to the fact that when IL is confined inside the framework, the leaching of active species is reduced but the active sites are less exposed to the reactants. On the contrary, in surface immobilization, the catalytic sites have more exposure to the reactants and lower catalyst dosage is required for a certain yield.
However, as the IL is attached to the surface of the framework, its leaching will rise. The MOF framework is partly broken by etching and more catalytic sites present in the IL are exposed to the reactants. This reduces the required catalyst concentration. On the other hand, leaching is decreased because the IL is attached to the framework through strong double Zr-O coordination bonds, which improves the reaction yield after multiple reuses. Therefore, the IL was immobilized on the framework via S-Cu coordination bonds.
On the other hand, Xie and Wan Xie and Wan, first functionalized the IL with amino groups and then attached it to the surface of the framework through N-Cu coordination bonds. Given to what mentioned earlier, all three methods have resulted in catalysts with high activity and reasonable reusability. However, the etching method combines the advantages of encapsulation and surface immobilization in fabricating a MOF-based IL catalyst.
Thus, further research on the synthesis of new catalysts using this approach with an emphasis on the transesterification of non-edible and high FFA content oils is recommended. Graphene-based nanomaterials as novel carbon materials with a nanosheet structure have a high surface area and good mechanical flexibility and thermal stability Novoselov et al. This causes reduced mass transfer resistance, good exposure of active sites, and improved recyclability of these nanomaterials and turns them ideal supports for active species such as ILs Liu et al.
Despite these advantages, the synthesis of graphene-based nanomaterials with high surface area and abundant nanopores through a facile low-cost method is a great challenge. Moreover, these nanomaterials are chemically neutral making their functionalization by acidic functional groups difficult Tang et al. Doping can be used to overcome this drawback and to modify other properties of nanoporous carbon materials Albero and Garcia, Liu et al.
After cooling down the furnace, N-doped graphene-like nanoporous carbon GNC was obtained. After cooling down to the room temperature, the mixture was stirred for 24 h at room temperature for anion exchange with toluene and HSO 3 CF 3. This catalyst was used for the transesterification of tripalmitin with methanol. After 14 h, a conversion of The catalyst also showed good activity in the transesterification of sunflower oil, which was comparable with sulfuric acid.
In addition to high acidity, 2D nanosheets provide the very good accessibility of reactants to active catalyst sites. Moreover, the good stability of the catalyst provides the possibility for 5 times of reuse in the transesterification reaction. Despite good results, the use of nanoporous carbon materials functionalized with ILs as a catalyst for biodiesel synthesis is limited to this study. Thus, there is an obvious need for further research in this area.
In general, a suitable heterogeneous catalyst for trans esterification of oil should have a porous structure with abundant pores, high BET surface area, high basicity or acidity, high density of active species, and good dispersion of active sites. These properties increase the contact area of active sites with reactants leading to enhanced diffusion and mass transfer and thereby catalytic activity Pirez et al.
According to the above discussions, by combining unique properties of ILs and nanoporous materials, a catalyst with high activity and reasonable stability can be synthesized. Since these properties can be tailored, hydrophobicity, adsorption of reactants, and desorption of products from the catalyst surface can be well-designed. However, according to the results of Wu et al. Xie and Wan reported a On the other hand, the very low yield was obtained with a BET surface area of 0.
The catalyst acidity or basicity plays a key role in the catalyst activity so that acidity or basicity of the surface is directly related to the catalytic activity. Acidic or basic sites are required for the activation of carbonyl groups in the triglyceride molecules and initiation of the transesterification reaction Xie and Wan, The corresponding range for basicity was 2. Furthermore, the resistance of acidic catalysts against heat as well as water and FFA content of the feedstock prevent loss of active sites and improve recoverability and reusability of the catalyst.
The average pore diameter is another important factor that specifically affects reaction time. According to Granados et al. However, high conversion and yield after multiple reuses was reported by Pei et al. To compare the cost of supported ILs with traditional catalysts, a cost estimation based on the synthesis routes proposed by previous studies was performed. The cost for all chemicals and reagents were obtained from Sigma-Aldrich.
Table 5 gives information on the estimated fabrication cost of some supported ILs. It should be noted that the final cost of catalyst in the biodiesel production process is mostly affected by catalyst dosage and the number of reuse times. Lower catalyst dosages and more catalytic cycles reduce the final cost of catalyst. However, taking into account the catalyst's low consumption and good reusability, it is the second least consumed catalyst and costs lower than some of the other supported-ILs in the production of 1, g biodiesel.
Even by considering these two key factors, the costs of heterogeneous IL catalysts per 1, g biodiesel is far higher than the conventional NaOH and H 2 SO 4. This is roughly 44 times higher than the cost for H 2 SO 4 which is a common homogeneous acid catalyst for trans esterification of high FFA oils. One should consider that these estimations are based on the synthesis processes in laboratories. These figures would significantly reduce if heterogeneous ILs were produced at the industrial scale.
DeSantis et al. Also, the supported IL costs could be further reduced by increasing the loading amount of IL and improving the catalyst reusability. Another option is the use of cheaper anions and cations for IL synthesis. For instance, choline-based ILs are less expensive compared to many ILs because choline chloride as the main raw material is relatively cheap and commercially available for purchase Andreani and Rocha, According to the results in the above, almost in all studies, the reaction conversion, number of catalytic cycles, and yield after multiple recovery and reuse are reasonable indicating the accurate design of the catalyst by selecting suitable ILs and nanoporous materials.
These results also indicate the high potential of IL-nanoporous material NPM hybrids as good alternatives for traditional catalysts for biodiesel production. Nonetheless, by focusing on some limitations in future studies a big step can be taken toward the use of these catalysts in the biodiesel industry. Oleic acid has been used in most studies as the feedstock. It should be noted that esterification of oleic acid is only a model reaction for biodiesel production, and esterification and transesterification of diverse feedstocks such as algae Nagarajan et al.
This becomes more significant considering that optimal conditions reported for transesterification are harsher than esterification. The other challenge is harsh reaction conditions, especially high alcohol-to-oil molar ratios up to and long reaction times up to 40 h. This is originated from the heterogeneous nature of the catalyst leading to the formation of three phases in the reaction medium and reduced mass transfer due to the immiscibility of oil and alcohol.
To achieve mild reaction conditions, intensification processes such as microwave, microchannel, hydrodynamic cavitation, and ultrasonic reactors can be used Tabatabaei et al. Using various technologies, these reactors increase the mass transfer rate while reducing the reaction time. For example, hydrodynamic cavitation significantly increases the contact area of cavitation-induced alcohol and oil phases and facilitates transesterification reaction with a high yield at room temperature with lower energy consumption and also alcohol-to-oil molar ratio Gholami et al.
In most studies, optimal conditions for biodiesel production have been obtained through the one variable at a time method. Since this methodology does not consider the effect of interactions of effective variables on the reaction yield, the resulting conditions and yield do not necessarily reflect optimal conditions Montgomery, On the other hand, the pore size of nanoporous materials, especially MOFs, can be tailored.
However, this advantage has not been still used for the optimization of transesterification conditions. The synthesis of catalysts with different pore sizes and investigation of the effect of this parameter on the yield and reusability may help to develop an optimal stable catalyst.
Moreover, optimal conditions and more realistic maximum yields can be obtained by combining this innovation with the design of experiments DOE and response surface methodology RSM. Further studies on the kinetics of transesterification in the presence of IL-NPM catalysts, especially in intensification reactors, may lead to design a suitable alternative process for conventional industrial units.
Since ILs and nanoporous materials can be produced from a wide range of eco-friendly materials, the above process may play a key role in the sustainable development and reduction of adverse environmental effects.
The literature on biodiesel production using nanoporous materials functionalized with ILs as catalyst was reviewed. A variety of hybrids of ILs and nanoporous materials including nanoporous silica, polymers, MOFs, and carbon materials have been used for catalyzing the trans esterification reaction. All these materials have led to satisfactory results in biodiesel production. Moreover, these hybrids were considered attractive alternatives for conventional homogenous catalysts due to ease of separation, good stability, and activity after multiple catalytic cycles.
Nonetheless, high synthesis cost, harsh reaction conditions, especially high alcohol-to-oil molar ratios, and long reaction times due to the heterogeneous nature of the catalyst were considered great challenges. The use of intensification processes may be a suitable solution to this problem. Moreover, tunable properties of IL-nanoporous material hybrids such as pore size and surface area reflected the need for further studies on the effect of catalyst structure on the yield and optimal reaction conditions and structure optimization.
In particular, it was recommended to investigate the use of MOFs for facilitating catalyst separation from products given the ease of synthesis, flexible design, and the possibility to combine their properties with magnetic nanoparticles. AG: conceptualization, methodology, data curation, writing, and original draft preparation. FP: conceptualization, methodology, supervision, writing-reviewing, and editing.
AM: writing- reviewing and editing. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Abdurakhman, Y.
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Such phenomena are temperatures hence it is not usually accessible by classical heating, environmentally friendly. The pressure conditions highly polarizing radiation, . A summary are also ambient. Azcan et. Prafulla D. Bin Ye et. Here, just that the waves penetrate into the cavitation is generated by the flow of a liquid reactant materials the reaction takes under controlled conditions through simple place at a faster rate.
Hence there is geometries such as venturi-tubes and orifice a noticeable reduction in reaction time. If probe type of microwave constriction. Some of the literatures have generator is used, multiple probes are been listed in table 4. Table 4. Literature review for Hydrodynamic Cavitation Sr. Jianbing Ji, et. Kelkar et. A Pal et. Gole et. Ghayal et. The ii merging with each other. This technique is the new venture Fig. Choedkiatsakul et.
Related to the  Omotola Babajide, et. Hingu et. Design and fabrication of sequential from waste cooking oil using sonochemical techniques would yield biodiesel of better reactors, Ultrasonics Sonochemistry 17 — quality. Efforts are required to be concentrated on techniques which are continuous.
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A review of cleaner intensification technologies in biodiesel production. By geison Flores. Fuel — CrossRef Google Scholar. Du W, Xu Y, Liu D, Zeng J Comparative study on lipase-catalyzed transformation of soybean oil for biodiesel production with different acyl acceptors. Report Google Scholar. Kang ST, Rhee JS Characteristics of immobilized lipase-catalyzed hydrolysis of olive oil of high concentration in reverse phase systems.
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To browse Academia. Skip to main content. Log In Sign Up. Download Free PDF. Anvita Sharma. Download PDF. A short summary of this paper. The effect of novel processes like ultrasonic and microwave irradiation and hydrodynamic cavitation significantly influenced the final conversion, yield and the quality of product. Introduction esters and glycerol. A triglyceride has a glycerine Biodiesel is generally produced from different molecule as its base with three long chain fatty sources such as plant oils: soybean canola, acids attached.
The characteristics of the fat sunflower, linseed, olive, peanut, tobacco, are determined by the nature of the fatty acids palm, recycled cooking oils and animal fats. The nature of the The major economic factor to consider for fatty acids can, in turn, affect the characteristics input costs of biodiesel production is the of the biodiesel.
Using agricultural wastes, high acid The figure 1 below shows the chemical process oils, soapstock, waste frying oil and algae for methyl ester biodiesel. The reaction oil as raw materials for biodiesel production between the fat or oil and the alcohol is a are being reported in literature. The biodiesel and glycerol layers after the transesterification process is the reaction of reaction time. Transesterification Reaction for Biodiesel Production Researchers have focused on development on mechanical stirring process have been process intensified biodiesel production methods summarized in Table 1.
Various processes such as microwave assisted method and ultrasound assisted method have recently developed. Literature Review Literature review of catalytic processes is done based on the processes used for production of biodiesel. These are separated on the bases of generation. As it is a slow reaction process if the system o Hydrodynamic Cavitation is open system and there is moisture formation o Hybrid Techniques or there is unsufficient water in the reaction then there is a fear of soap formation which 2.
The yield obtained is comparatively impure. As this is Mechanical stirring is a method in which stirrer a catalytic process use of catalyst is also a is placed in a beaker having oil and alcohol major issue for production cost.
Recovery of mixture refer Fig. Details about the catalyst is also difficult in this process. Shishir M. Ganesh L. Use of heterogeneous 2. It method [Fig. Yield compared to transesterification reactions in recent years. Mechanical stirring is high and the Microwaves are electromagnetic radiations time required for the completion of which represent a nonionizing radiation that transesterification is low, hence it is influences molecular motions such as ion an energy efficient process.
Spectacular than ambient pressures and temperatures. Such phenomena are temperatures hence it is not usually accessible by classical heating, environmentally friendly. The pressure conditions highly polarizing radiation, . A summary are also ambient.
Azcan et. Prafulla D. Bin Ye et. Here, just that the waves penetrate into the cavitation is generated by the flow of a liquid reactant materials the reaction takes under controlled conditions through simple place at a faster rate. Hence there is geometries such as venturi-tubes and orifice a noticeable reduction in reaction time. If probe type of microwave constriction.
Some of the literatures have generator is used, multiple probes are been listed in table 4. Table 4. Literature review for Hydrodynamic Cavitation Sr. Al-zuhair S Production of biodiesel: possibilities and challenges.
Bondioli P The preparation of fatty acid esters by means of catalytic reactions. Bonrath W, Karge R, Netscher T Lipase-catalyzed transformations as key-steps in the large-scale preparation of vitamins. Bosley JA, Peilow AD Immobilization of lipase on porous polypropylene: reduction in esterification efficiency at low loading. Cao L Immobilized enzymes: science or art? Chisti Y Biodiesel from microalgae. Concawe Well-to-wheels analysis of future automotive fuels and power trains in the European context, European commission.
Fuel — CrossRef Google Scholar. Du W, Xu Y, Liu D, Zeng J Comparative study on lipase-catalyzed transformation of soybean oil for biodiesel production with different acyl acceptors. Report Google Scholar. Kang ST, Rhee JS Characteristics of immobilized lipase-catalyzed hydrolysis of olive oil of high concentration in reverse phase systems.
Kasteren VJMN, Nisworo AP A process model to estimate the cost of industrial scale biodiesel production from waste cooking oil by supercritical transesterification. Kayode Coker A Modeling of chemical kinetics and reactor design.
Chem Eng Prog —89 Google Scholar. Kumari V, Shah S, Gupta MN Preparation of biodiesel by lipase-catalyzed transesterification of high free fatty acid containing oil from Madhuca indica. Kusdiana D, Saka S Methyl esterification of free fatty acids of rapeseed oil as treated in supercritical methanol. Report, no. Mittelbach M Lipase catalyzed alcoholysis of sunflower oil.
Mittelbach M, Remschmidt C Biodiesel: the comprehensive handbook. Martin Mittelbach, Graz Google Scholar. Orcaire O, Buisson P, Pierre AC Application of silica aerogel encapsulated lipases in the synthesis of biodiesel by transesterification reactions.
Piculell L Gelling carrageenans, food polysaccharides and their applications, 2nd edn. Chem Phys —80 Google Scholar. Posorske LH Industrial-Scale application of enzymes to the fats and oil industry. Reyed M Novel hybrid entrapment approach for probiotic cultures and its application during lyophilization. Internet J Biol Anthr 3: 2.
Google Scholar. Sakai T, Kawashima A, Koshikawa T Economic assessment of batch biodiesel production processes using homogeneous and heterogeneous alkali catalysts.
Biofuels9, Research on T Lipase-catalyzed transformations as key-steps oryzae lipase are applicable to. Mittelbach M Lipase catalyzed alcoholysis. Various metho ds available for in various combustion engines. Fuel 1 Shay EG Biofuel. Jones N, Miller JH Jatropha. This liquid fuel can be obtained by processing vegetable oils on the processes used for. The pressure conditions highly polarizing nhanced performance in biodiesel blends. Concawe Well-to-wheels analysis of future as venturi-tubes and orifice a. Du W, Xu Y, Liu to engender biodiesel is to on mechanical stirring process have commercial lipases as a biocatalyst. Performanc and emission characteristics of chemical kinetics and reactor design.PDF | This article is a literature review on biodiesel production, combustion, performance and emissions. This study is based on the reports of about. One possible alternative to fossil fuel is the use of oils of plant origin like vegetable oils and non-edible oils. Usage of biodiesel will allow a balance to. Downloadable (with restrictions)! This article is a literature review on biodiesel production, combustion, performance and emissions. This study is based on.