Patent GB-1103145-A (GB)
Title: Process for the preparation of organic esters
IPC: C07C/
Filed: 1965-06-01
Abstract: As stabilizers for polyethylene, polypropylene or polystyrene, use is made of esters of the formula <FORM:1103145/C3/1> in which a lower alkyl or lower alkylene group contains up to 6 carbon atoms, n is 1-6 and R is the non-hydroxylated residue of an organic compound containing n hydroxy groups, more particularly the residue of a monohydric aliphatic alcohol containing 7-30 carbon atoms, the residue of a di- or poly-hydric alcohol of 2-30 carbon atoms, the residue of an alicylic alcohol of 5-7 carbon atoms or the residue of a mercapto alcohol containing 4-40 carbon atoms and 1-3 non-terminal sulphide linkages (see Division C2). Specific esters described include tetra - [3 - (3,5 - di - tert. - butyl - 4 - hydroxyphenyl) propionyloxymethyl] methane, 1,2,3,4,5,6 - hexa - [3 - (3,5 - di - tert. - butyl - 4 - hydroxyphenyl) propionyloxy] hexane and 3 - (dodecylthio)propyl - 3 - (3,5 - di - tert. - butyl - 4 - hydroxyphenyl) propionate. No details of the stabilizing treatment are given.ALSO:As stabilizers for animal, vegetable and hydrocarbon and ester lubricating oils, use is made of esters of the formula <FORM:1103145/C4-C5/1> in which a lower alkyl or lower alkylene group contains up to 6 carbon atoms, n is 1-6 and R is the non-hydroxylated residue of an organic compound containing n hydroxy groups, more particularly the residue of a monohydric aliphatic alcohol containing 7-30 carbon atoms, the residue of a di- or poly-hydric alcohol of 2-30 carbon atoms, the residue of an alicyclic alcohol of 5-7 carbon atoms or the residue of a mercapto alcohol containing 4-40 carbon atoms and 1-3 non-terminal sulphide linkages (see Division C2). Specific esters described include tetra - [3 - (3,5 - di - tert. - butyl - 4 - hydroxyphenyl propionyloxymethyl] methane 1,2,3,4,5,6 - hexa - [3 - (3,5 - di - tert. - butyl - 4 - hydroxyphenyl) propionyloxy] hexane and 3 - (dodecylthio) propyl - 3 - (3,5-di - tert. - butyl - 4 - hydroxyphenyl) propionate. No details of the stabilizing treatment are given.ALSO:The invention relates to a process for the manufacture of esters of the formula <FORM:1103145/C2/1> in which a lower alkyl or lower alkylene group contains up to 6 carbon atoms, n is 1-6 and R is the non-hydroxylated residue of an organic compound containing n hydroxy groups, more particularly the residue of a monohydric aliphatic alcohol containing 7-30 carbon atoms, the residue of a di- or poly-hydric aliphatic alcohol of 2-30 carbon atoms, the residue of an alicyclic alcohol of 5-7 carbon atoms or the residue of a mercapto alcohol containing 4-40 carbon atoms and 1-3 non-terminal sulphide linkages.  The process consists in reacting an ester of the formula above, in which n is 1 and R denotes an alkyl group of 1-6 carbon atoms, with an alcohol of the formula (HO)nR in the presence of a hydride of an alkali or alkaline-earth metal, subject to the proviso that, when R contains only 1-6 carbon atoms and n is 1, the initial ester must contain fewer carbon atoms than the desired product.  The reaction may be effected at 70-150 DEG  C. under atmospheric or reduced pressure.  In typical examples, methyl 3 - (3,5 - di - tert. - butyl - 4-hydroxyphenyl) propionate reacts, in the presence of lithium or calcium hydride, (1) with pentaerythritol, to produce tetra-[3-(3,5-di - tert. - butyl - 4 - hydroxyphenyl) propionyloxymethyl] methane; (2) with 1,1,1-trimethylolpropane, to produce 1,1,1-tris-[3-(3,5-di - tert. - butyl - 4 - hydroxyphenyl) propionyloxymethyl] propane; (3) with sorbitol, to produce 1,2,3,4,5,6 - hexa - [3 - (3,5 - di - tert.-butyl - 4 - hydroxyphenyl) propionyloxy] hexane; (4) with 1,4-butanediol, to produce 1,4-bis - [3 - (3,5 - di - tert. - butyl - 4 - hydroxyphenyl) propionyloxy] butane; and (5) with n-dodecylthiopropanol, to produce 3-(dodecylthio) propyl - 3 - (3,5 - di - tert. - butyl - 4 - hydroxyphenyl) propionate. Other specified alcohols which may be used include decyl alcohol, octadecyl alcohol, ethylene glycol, 1,2-octanediol, glycerol, 1,2,3-butanetriol, cyclopentanol, inositol, 2,21-diethanol sulphide and n - octylthioethylthioethanol.  The products are useful as stabilizers for aliphatic ester lubricants and certain other materials (see Divisions C3 and C5).  Methyl 3 - (3,5 - di - tert. - butyl - 4 - hydroxyphenyl) propionate, used as starting material in the examples, is obtainable by reacting 2,6-di-tert.-butylphenol with methyl acrylate.  A number of similar esters similarly obtainable are also specified.  Ethyl 2 - (3,5 - di - tert. - butyl - 4 - hydroxyphenyl) isobutyrate, another specified starting material, is obtainable by reacting 2,6-di-tert.-butyl-phenol with ethyl a -bromo-a -methyl-propionate. Ethyl (3,5 - di - tert. - butyl - 4 - hydroxyphenyl) acetate, another specified starting material, is obtainable by treating 3,5-di-tert.-butyl-4-hydroxybenzyl cyanide with hydrogen chloride. Methyl (3,5 - di - tert. - butyl - 4 - hydroxyphenyl) acetate, another specified starting material, is obtainable by esterifying the corresponding acid with methanol in the presence of p - toluene - sulphonic acid.  Methyl 6 - (3,5-di - tert. - butyl - 4 - hydroxyphenyl) hexanoate is similarly obtainable from 6-(3,5-di-tert.-butyl-4-hydroxyphenyl) hexanoic acid.