Patent GB-587523-A (GB)
Title: Improvements in or relating to the alcoholysis of fatty glycerides
IPC: C11C3/04
Filed: 1943-10-15
Abstract: In a process for the alcoholysis of fatty glycerides with an aliphatic alcohol having 1-6 carbon atoms in the molecule, the fatty glyceride, alcohol and alcoholysis catalyst are brought together to form a liquid pool and material is withdrawn from the pool, the rates of introduction into and withdrawal from the pool being chosen so that a substantially homogeneous phase of partially reacted material is maintained in the pool.  Then after glycerine and alkyl esters of the fatty acids have ultimately been obtained from the material withdrawn from the pool, the remaining withdrawn material is returned to the system for retreatment with fresh reaction materials.  The partial alcoholysis may be accomplished by keeping the fatty glyceride and the alcohol in contact in the pool for a time insufficient for the reaction to go to completion or alternatively by employing an amount of alcohol and catalyst insufficient for complete reaction with the quantity of fatty glyceride used.  Numerous treatments of the material withdrawn from the pool in order to obtain the glycerine and alkyl esters of fatty acids are described.  Fatty glycerides specified are coconut, palm, olive, cottonseed, corn, tung, whale, fish and soya bean oils and tallow, and these may be used unrefined or freed from moisture and free fatty acid.  If desired, the alcohol refining process of Specification 578,751 may be employed.  The alcoholysis catalyst may be sodium hydroxide, sodium methylate, sodium carbonate, lime, boron trifluoride, aluminium chloride, glycerine sulphate, sulphuric acid, an organic sulphuric acid or an organic sulphonate while the alcohol may be methyl, ethyl, a propyl, a butyl or an amyl alcohol.  Mixtures of methyl alcohol with ethyl or other higher alcohols may be employed and reference is made to a mixture of methyl alcohol, ethyl alcohol, ethyl acetate and gasoline.  The alkyl esters of fatty acids produced according to the process may be converted to soaps by saponification with sodium and potassium hydroxides, carbonates or silicates, methyl morpholine, piperidine, alkylamines, alkanol amines and other organic and inorganic bases and alkaline materials and mixtures of these.  In saponifying the esters, they may be mixed with mono esters of polyhydric alcohols, such as ethylene glycol monostearate, propylene glycol monolaurate, trimethylene glycol monoesters of olive oil fatty acids, glyceryl alpha- or beta-monostearate, mannitol monoesters of coconut oil fatty acids sorbitol monopalmitate and erythritol mono-oleate. Mixtures of any of these monoesters with the corresponding di-, tri-, or poly-esters may also be added.  Soap builders, inert materials and anti-oxidants or other modifying agents may be added to either or both of the ester and the saponifying agent or to the soap.  Adjuvant materials mentioned are soaps derived from fatty, naphthenic, alkylated naphthenic or resin acids, sulphated and sulphonated organic compounds, sodium carbonate, sodium silicates, trisodium phosphates, borax, sodium tetraphosphate, sodium bicarbonate, sodium sulphate, sodium chloride, sodium acetate, sodium hypochlorite, sodium thiosulphate, sodium perborate, sodium tartrate, sodium citrate, sodium oxalate, corresponding ammonium, substituted ammonium and potassium salts, aluminium chloride, mercuric chloride, copper and lead salts, silica, kieselguhr, silica gel, feldspar, precipitated chalk, pumice, infusorial earth, bentonite, talc, starch, Irish moss, sugar, methyl cellulose, agar, gum tragacanth, gum arabic, polyvinyl alcohols, ethyl alcohol, glycerol, cyclohexanol, naphtha, benzene, kerosene, turpentine and decalin. Instead of saponifying the alkyl esters, they may be hydrolysed to form free fatty acid and alcohol, and the free fatty acid may be neutralised to form a soap.  In examples, (a) dried coconut oil is reacted with methyl alcohol in presence of sodium hydroxide and the material withdrawn from the pool is allowed to react further until it separates into two layers, the lower layer consisting of glycerine; unreacted alcohol is removed from the top layer by distillation and further glycerine is settled out from the still residue; alkyl esters are then distilled off and the still residue from this second distillation, comprising unreacted and partially reacted oil, together with the unreacted alcohol are returned to the pool, (b) refined and anhydrous corn oil is reacted with ethyl alcohol in presence of sodium hydroxide, or alternatively cottonseed oil is reacted with methyl alcohol in presence of sodium hydroxide, and the material withdrawn from the pool is distilled to remove unreacted alcohol; the still residue is allowed to separate into two layers and the lower glycerine layer is withdrawn; alkyl esters and residual glycerine are distilled off from the upper layer and the still residue of this second distillation, consisting of mono-, di- and tri-glycerides, is returned to the pool; the alkyl esters are separated from the residual glycerine by settling, (c) coconut oil, refined by methyl alcohol extraction, is reacted with a mixture of methyl and ethyl alcohols in presence of sodium methylate and the material withdrawn from the pool is allowed to react further until it separates into two layers, the lower layer consisting of glycerine; the upper layer is reacted with additional methyl alcohol, ethyl alcohol and sodium methylate, and glycerine is again settled off; the upper layer from this second settling is run to a still where alkyl esters and unreacted alcohol are separately distilled off and the distillation residue is returned to the pool, (d) a dried mixture of tallow and coconut oil is reacted with methyl alcohol in presence of sodium hydroxide and the material withdrawn from the pool is reacted with additional methyl alcohol and sodium hydroxide until a lower glycerine layer separates; the upper layer is treated in the same way as the top layer of (a) above, (e) refined anhydrous coconut oil is reacted with methyl alcohol in presence of sodium methylate and the material withdrawn from the pool is reacted with additional methyl alcohol and sodium methylate until a lower glycerine layer separates; the upper layer is again reacted with additional methyl alcohol and sodium methylate until a lower glycerine layer separates; the upper layer from this second separation is distilled to remove unreacted alcohol and residual glycerine is settled from the still residue; the upper layer from the third separation is distilled to remove alkyl esters and the still residue is returned to the pool, (f) cottonseed oil is reacted with ethyl alcohol in presence of sodium hydroxide and the material withdrawn from the pool is acidified with sulphur dioxide and a lower glycerine layer then settled off; unreacted alcohol and then alkyl esters together with any residual glycerine are distilled off from the upper layer; the still residue is returned to the pool while alkyl esters and residual glycerine are separated by settling and (g) coconut oil is reacted with methyl alcohol in presence of benzenesulphonic acid and the material withdrawn from the pool is reacted with additional methyl alcohol and benzene sulphonic acid, whereupon the catalyst is neutralized with sodium bicarbonate; a lower glycerine layer is separated from the neutralized material while the upper layer is treated in the same way as the top layer of (a) above.  Specification 587,524 also is referred to.  The Specification as open to inspection under Sect. 91 refers to a process for the alcoholysis of fatty glycerides which comprises reacting a fatty glyceride with an alcohol to produce a liquid body containing alkyl esters, glycerine and partially reacted glycerides, removing alkyl esters and glycerine from said liquid body and reworking the partially reacted glycerides.  The alcoholysis of woolfat and tall oil is mentioned and the use of aryl-substituted alcohols such as benzyl alcohol is described. This subject-matter does not appear in the Specification as accepted.ALSO:In a process for the alcoholysis of fatty glycerides with an aliphatic alcohol having 1-6 carbon atoms in the molecule, the fatty glyceride, alcohol and alcoholysis catalyst are brought together to form a liquid pool and material is withdrawn from the pool, the rates of introduction into and withdrawal from the pool being chosen so that a substantially homogeneous phase of partially reacted material is maintained in the pool.  Then after glycerine and alkyl esters of fatty acids have ultimately been obtained from the material withdraw from the pool, the remaining withdrawn material is returned to the system for retreatment with fresh reaction materials.  The partial alcoholysis may be accomplished by keeping the fatty glyceride and the alcohol in contact in the pool for a time insufficient for the reaction to go to completion or alternatively by employing an amount of alcohol and catalyst insufficient for complete reaction with the quantity of fatty glyceride used.  Numerous treatments of the material withdrawn from the pool in order to obtain the glycerine and alkyl esters of fatty acids are described.  Fatty glycerides specified are coconut, palm, olive, cotton seed, corn, tung, whale, fish and soyabean oils and tallow, and these may be used unrefined or freed from moisture and free fatty acid.  If desired, the alcohol refining process of Specification 578,751 may be employed.  The alcoholysis catalyst may be sodium hydroxide, sodium methylate, sodium carbonate, lime, boron trifluoride, aluminium chloride, glycerine sulphate, sulphuric acid, an organic sulphur acid or an organic sulphonate, while the alcohol may be methyl, ethyl, a propyl, a butyl or an amyl alcohol.  Mixtures of methyl alcohol with ethyl or other higher alcohols may be employed and reference is made to a mixture of methyl alcohol, ethyl alcohol, ethyl acetate and gasoline.