Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/02—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only
  • C10L1/023—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only for spark ignition
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
  • C11C3/00—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom
  • C11C3/04—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom by esterification of fats or fatty oils
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
  • C11C3/00—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom
  • C11C3/04—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom by esterification of fats or fatty oils
  • C11C3/10—Ester interchange

Definitions

• the present invention relates to a process for the manufacture of methyl esters of fatty acids from a natural fat or oil by transesterification with methanol in the presence of a catalyst.
• Methyl esters derived from natural oil or fat have become important in the oleochemical industry as fuels or as raw materials for the manufacture of several derivatives, such as fatty alcohols or fatty alkanolamides. These methyl esters can be produced by esterification of fatty acids, but the conventional process used to manufacture these methyl esters is catalytic transesterification or methanolysis of the triglycerides, that is to say an ester substitution, with an excess of methanol.
• the transesterification which is carried out according to the following reaction scheme: oil or fat + methanol ⁇ methyl esters + glycerol the glycerol molecule in the triglyceride is replaced by three methanol molecules.
• One of the essential aims of the present invention consists in remedying the aforementioned drawbacks of existing methods and in providing an industrially and economically valid method making it possible to obtain methyl esters in high yield and which does not in particular require the neutralization of fatty acids and which does not use or give corrosive products.
• the process according to the invention consists in using, as catalyst, an organotitanate-based catalyst.
• the organotitanate is chosen from the group comprising tetraalkyl orthotitanates, monomeric and polymeric cresyl titanates, titanium lactate, stearic titanate, 2-ethylhexyl titanate, n-butyl titanate polymer, titanium acetylacetonate, triethanolamine titanate and octylene glycol titanate and mixtures of two or more of these two substances.
• a tetraalkyl orthotitanate containing from 1 to 5 carbon atoms is used as organotitanate, the tetrabutyl orthotitanate being particularly suitable in this regard.
• the catalyst comprises zinc acetylacetonate, the amount by weight of zinc acetylacetonate being from 2 to 5% and preferably 3% relative to the titanium of the catalyst.
• the oil or the fat, the methanol and the catalyst are mixed before being subjected to transesterification.
• the transesterification is carried out at a pressure of 35 to 60 bars, preferably from 45 to 55 bars and at a temperature of 150 to 300 ° C, preferably from 200 to 250 ° C, a pressure between 48 and 50 bars and a temperature between 222 and 227 ° C proving to be particularly advantageous.
• the present invention also relates to the methyl esters of fatty acids as thus obtained and their use as fuels in mixture or not with other fuels.
• the present invention therefore relates to a process for the production of methyl esters of acids.
• organotitanates which may be suitable for this purpose, mention will be made in particular of tetraalkyl orthotitanates, in particular tetraalkyl orthotitanates containing from 1 to 5 carbon atoms, cresyl titanates monomer and polymer, titanium lactate, stearic titanate, titanate 2-ethylhexyl, polymeric n-butyl titanate, titanium acetylacetonate, triethanolamine titanate and octylene glycol titanate.
• tetraalkyl orthotitanates in particular tetraalkyl orthotitanates containing from 1 to 5 carbon atoms, cresyl titanates monomer and polymer, titanium lactate, stearic titanate, titanate 2-ethylhexyl, polymeric n-butyl titanate, titanium acetylacetonate, triethanolamine titanate and octylene glycol titanate.
• C1-C5 tetraalkyl orthotitanates are particularly advantageous; examples of these are especially tetraethyl, tetrapropyl, tetraisopropyl, tetrabutyl and tetraisobutyl orthotitanates.
• Tetrabutyl orthotitanate is the preferred organotitanate as a catalyst.
• the catalyst can also comprise a small amount of zinc acetylacetonate, which increases the activity of the organotitanate, the amount by weight of zinc acetylacetonate of the catalyst being from 2 to 5% and preferably from 3% relative to the titanium.
• the oil or the fat, the methanol and the catalyst are mixed before being introduced into the transesterification reactor with the aim, on the one hand, of obtaining a fine dispersion of the catalyst in the reaction mass. and, on the other hand, to protect the catalyst from too long a presence with the hydroxyl radicals of methanol.
• This preliminary mixing, when one is carried out, and the transesterification are generally carried out at a pressure of 35 to 60 bars and at a temperature of 150 to 300 ° C., a pressure of 45 to 55 bars and a temperature from 200 to 250 ° C being preferable. Particularly advantageous results are obtained, however, with a pressure between 48 and 50 bars and a temperature between 222 and 227 ° C.
• the oil or fat and methanol are generally maintained in the presence of the organotitanate catalyst for approximately 0.5 to 4 hours, and preferably for 2 to 3 hours.
• a good reaction yield is obtained when the amount by weight of catalyst per tonne of oil or fat is between 0.5 and 1.5 kg and preferably when it is of the order of 1.3 kg.
• the fat or oil must be mixed with an excess of methanol which corresponds to 1-3 times the stoichiometric quantity necessary to replace the glycerol. bound in fat or oil.
• the oil or fat to be mixed with methanol can contain free acidity, i.e. a free fatty acid content of up to 5% and therefore should not normally be neutralized.
• the orthotitanate catalyst requires an oil or fat with a low water and phosphorus content, the oil or fat will therefore have to be pretreated before its possible preliminary mixing with methanol and the catalyst and the reaction. transesterification.
• the pretreatment of oil or fat comprises two stages, namely acid degumming to reduce its phosphorus content to 50 ppm or less and dry pretreatment followed by filtration, for example on land bleaching, to reduce humidity to about 0.01% and phosphorus content to 15 ppm or less.
• natural oil or fat it is understood in the context of the present invention an oil or fat having a linear chain of fatty acids.
• Vegetable oils are all usable, in particular rapeseed oil, palm oil and palm kernel oil. Animal fats are also all usable.
• the preheated liquid mixture comprising the oil or fat to be treated, methanol, of a purity of at least 99% , advantageously 99.5% and the catalyst is preferably introduced continuously by a high pressure pump into the reactor. It crosses the transesterification zone maintained at the specified temperature and pressure. During the transesterification reaction, the catalyst is consumed and finally removed as a residue. It will be noted, in this regard, that it is not necessary for the oil or the fat, the methanol and the catalyst to be mixed before introduction into the reactor.
• the mixing can take place partly or completely in the reactor.
• the oil and the catalyst can be mixed and this mixture can be introduced into the reactor at the same time as methanol, or else the three components can be introduced simultaneously into the reactor and be mixed there.
• the product leaving the reactor is then subjected instantaneous evaporation in a first separator where the excess methanol is evaporated. This evaporated methanol is recycled after condensation and distillation and reused in transesterification. The mixture is then transferred to a second separator which removes the last traces of methanol.
• the mixture of methyl esters and glycerol is introduced into a decanter.
• the upper phase consists of methyl esters and the lower phase consists of glycerol. Glycerol does not require any refining and it can be directly concentrated from 40-50% to 82-88%.
• Pharmacopoeial grade glycerol is obtained by distillation of the concentrated product.
• the glycerol present in the methyl esters is separated by washing against the current with demineralized water. If necessary, the methyl esters are distilled.
• the purity of the methyl esters before distillation is greater than 95%.
• methyl esters obtained according to the process of the invention are used as fuel in mixture with other fuels, for example at a rate of 50/50 with diesel, they must not be distilled but only dried to a moisture content less than 0.05%. If they are used as 100% fuel or as a raw material for oleochemical derivatives, they must be distilled to a purity higher than 98.5%.
• These fatty acid methyl esters can also be converted by hydrogenation in the presence of a copper chromite catalyst to fatty alcohols. Conversion to alkanolamides, sulfonated esters or other derivatives is possible by known conventional reactions.
• the methyl esters obtained also have a purity of more than 95% .
• Example 1 is repeated, but with rapeseed oil in place of palm and / or palm kernel oil. Similar results are obtained.
• Methyl esters are also obtained with a purity of more than 95%.
• the process for preparing methyl esters according to the invention is extremely simple and economical to carry out.
• the crude oil or fat should only be degummed and dried and does not require, as in conventional processes, a step of removing fatty acids by chemical means (alkaline neutralization) or by physical means (steam entrainment).
• the crude glycerol obtained contains very few non-volatile products and does not require either chemical refining or separation of the soaps before concentration.
• the crude methyl esters obtained also have a very high purity.
• the reactor and the accessories can be constructed essentially of mild steel and, for example, partially in ordinary SS 304 stainless steel. Besides the fact that the process can be applied continuously, the consumption of catalyst is also very low and will have little influence on the purity of the final products and on the operating costs of the process.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Fats And Perfumes (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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Citations (8)

• 1993
  • 1993-11-22 EP EP93870224A patent/EP0654528A1/de not_active Withdrawn

Patent Citations (8)

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