Patent GB-587532-A (GB)
Title: Improvements in or relating to alcoholysis of fatty glycerides
IPC: C11C3/04
Filed: 1944-02-16
Abstract: A fatty glyceride is reacted with a monohydric or polyhydric alcohol in the presence of an alcoholysis catalyst, then the influence of the catalyst is removed by the addition of a neutralizing agent, unreacted alcohol is removed and glycerine recovered from the reaction products.  Suitable glycerides are coconut, palm, olive, cottonseed, soyabean, corn, tung, whale and fish oils and tallow, while alcoholysis catalysts mentioned are sodium hydroxide, sodium methylate, sodium carbonate, barium oxide, lime, tetramethyl ammonium hydroxide, hydrochloric, trichloracetic, phosphoric, sulphuric and organic sulphonic acids, aluminium chloride, boron fluoride, glycerine monoacid sulphate and alkyl sulphuric acids.  The alcohol employed may be a saturated alphatic monohydric alcohol containing one to about six carbon atoms in the molecule or a polyhydric alcohol such as ethylene glycol, propylene glycol, trimethylene glycol, the amylene glycols, mannitol, sorbitol and erythritol.  Where an alkaline alcoholysis catalyst is employed its influence may be removed by neutralizing or partially neutralizing with acetic, hydrochloric, sulphuric, phosphoric, boric, benzenesulphonic, or higher fatty acid or sulphur dioxide, while an acid catalyst may be neutralized or partially neutralized with caustic soda, soda ash, soap, sodium tetraborate or sodium acetate.  Although a refined fatty glyceride may be employed in the alcoholysis, the presence in the glyceride of moisture or free fatty acid may be tolerated.  The alcoholysis reaction may be carried to completion in one step or, as described in Specification 587,523, in more than one stage, or the reaction may be carried only so far as the production of fatty acid partial esters of a polyhydric alcohol. Various treatments for recovering glycerine and other reaction products from the reaction mixture are described.  In examples, (a) coconut oil is reacted with methyl alcohol in presence of sodium hydroxide and the reaction mixture neutralized with an alcoholic solution of glacial acetic acid, (b) cottonseed oil is reacted with ethyl alcohol in presence of concentrated sulphuric acid and the reaction mixture is neutralized with sodium acetate, (c) tallow, which may contain moisture and free fatty acid, is reacted with methyl alcohol in presence of sodium hydroxide and the reaction mixture neutralized with stearic or glacial acetic acid, (d) coconut oil is reacted with methyl alcohol in presence of concentrated sulphuric acid and the reaction mixture is partially neutralized with an alcoholic solution of sodium hydroxide, neutralization being completed with an alcoholic solution of sodium coconut oil soap.  Then, in each of these examples, unreacted alcohol is volatilised off, the residue is distilled and the distillate is allowed to settle into a lower layer of glycerine and an upper layer containing alkyl esters of fatty acids, the layers being then separated.  In other examples, (e) sesame oil is reacted with methyl alcohol in presence of sodium hydroxide and the reaction mixture neutralized with dilute sulphuric acid; the neutralized mixture is allowed to settle into a lower layer of glycerine and an upper layer containing alkyl esters of fatty acids, and unreacted alcohol is distilled from the top layer; the residue is again allowed to settle into two layers, methyl esters are distilled from the top layer and the still residue is returned to the alcoholysis vessel for recycle, (f) coconut oil is reacted with ethyl alcohol in presence of sodium hydroxide and the reaction mixture neutralized with sulphur dioxide; the neutralized mixture is allowed to settle into a lower layer of glycerine and an upper layer containing alkyl esters of fatty acids, and the upper layer is distilled first to remove unreacted alcohol and then ethyl esters; the still residue is returned to the alcoholysis vessel for recycle, (g) cottonseed oil is reacted with propylene glycol in presence of concentrated sulphuric acid and the reaction mixture neutralized with sodium hydroxide; fatty acid mono-esters of propylene glycol are distilled from the neutralized mixture.  Specifications 578,751, 587,524 and 587,533 also are referred to.ALSO:Esters of fatty acids are prepared by reacting a fatty glyceride with a monohydric or polyhydric alcohol in the presence of an alcoholysis catalyst, then removing the influence of the catalyst by the addition of a neutralising agent, removing unreacted alcohol and finally recovering the reaction products from the mixture.  Suitable glycerides are coconut, palm, olive, cottonseed, soyabean, corn, tung, whale and fish oils and tallow, while alcoholysis catalysts mentioned are sodium hydroxide, sodium methylate, sodium carbonate, barium oxide, lime, tetramethyl ammonium hydroxide, hydrochloric, trichloracetic, phosphoric, sulphuric, alkyl sulphuric and organic sulphonic acids, aluminium chloride, boron fluoride and glycerine mono-acid sulphate.  The alcohol employed may be a saturated aliphatic monohydric alcohol containing one to about six carbon atoms in the molecule or a polyhydric alcohol such as glycerine, ethylene glycol, propylene glycol, trimethylene glycol, the amylene glycols, mannitol, sorbitol and erythritol.  Where an alkaline alcoholysis catalyst is employed its influence may be removed by neutralising or partially neutralising with acetic, hydrochloric, sulphuric, phosphoric, boric, benzenesulphonic or higher fatty acid or sulphur dioxide, while an acid catalyst may be neutralised or partially neutralised with caustic soda, soda ash, soap, sodium tetraborate or sodium acetate.  Although a refined fatty glyceride may be employed in the alcoholysis, the presence in the glyceride of moisture or free fatty acid may be tolerated.  The alcoholysis reaction may be carried to completion in one step or, as described in Specification 587,523, in more than one stage, or the reaction may be carried only so far as the production of fatty acid partial esters of a polyhydric alcohol.  Various treatments for recovering the reaction products from the reaction mixture are described. In examples: (a) coconut oil is reacted with methyl alcohol in presence of sodium hydroxide and the reaction mixture neutralised with an alcoholic solution of glacial acetic acid; (b) cottonseed oil is reacted with ethyl alcohol in presence of concentrated sulphuric acid and the reaction mixture is neutralised with sodium acetate; (c) tallow, which may contain moisture and free fatty acid, is reacted with methyl alcohol in presence of sodium hydroxide and the reaction mixture neutralised with stearic or glacial acetic acid; (d) coconut oil is reacted with methyl alcohol in presence of concentrated sulphuric acid and the reaction mixture is partially neutralised with an alcoholic solution of sodium hydroxide, neutralisation being completed with an alcoholic solution of sodium coconut oil soap.  Then in each of these examples, unreacted alcohol is volatilised off, the residue is distilled and the distillate is allowed to settle into a lower layer of glycerine and an upper layer containing alkyl esters of fatty acids, the layers being then separated.  In other examples, sesame oil is reacted with methyl alcohol in presence of sodium hydroxide and the reaction mixture neutralised with dilute sulphuric acid; the neutralised mixture is allowed to settle into a lower layer of glycerine and an upper layer containing alkyl esters of fatty acids, and unreacted alcohol is distilled from the top layer; the residue is again allowed to settle into two layers, methyl esters are distilled from the top layer and the still residue is returned to the alcoholysis vessel for recycle; (f) coconut oil is reacted with ethyl alcohol in presence of sodium hydroxide and the reaction mixture neutralised with sulphur dioxide; the neutralised mixture is allowed to settle into a lower layer of glycerine and an upper layer containing alkyl esters of fatty acids, and the upper layer is distilled first to remove unreacted alcohol and then ethyl esters; the still residue is returned to the alcoholysis vessel for recycle; (g) cottonseed oil is reacted with propylene glycol in presence of concentrated sulphuric acid and the reaction mixture neutralised with sodium hydroxide; fatty acid mono-esters of propylene glycol are distilled from the neutralised mixture; (h) tallow is reacted with glycerine in presence of concentrated sulphuric acid and the reaction mixture is neutralised with a solution of sodium hydroxide in glycerine; glycerine is distilled off from the neutralised reaction mixture leaving monoglycerides of fatty acids; (i) tallow is reacted with glycerine in presence of sodium hydroxide and the reaction mixture is allowed to settle into two layers in order to remove part of the glycerine as a lower layer; the upper layer is neutralised with glacial acetic acid and extracted with ether; ether is volatilised from the extract and monoglycerides of fatty acids distilled from the residue. Specifications 578,751, 587,524 and 587,533 also are referred to.  The Specification as open to inspection under Sect. 91 refers to the alcoholysis of fatty acid esters in which at least one of the alcohols concerned, i.e. the free or combined alcohol, is a polyhydric alcohol, and mentions benzyl alcohol as a free alcohol and wool fat as a fatty acid ester.  In an example, methyl laurate is reacted with propylene glycol in presence of sodium hydroxide and the reaction mixture is neutralized with concentrated sulphuric acid. Lauric acid mono- and di-esters of propylene glycol are distilled from the neutralised reaction mixture.  This subject-matter does not appear in the Specification as accepted.