Verfahren zur Herstellung gemischter Glykol-Ester

摘要

The invention comprises complex esters of the general formula: wherein n is a number from 2 to 10, the R1's represent the residues of dicarboxylic acids at least one being saturated aliphatic and at least one being aromatic, R2 is the residue of an alkylene glycol and R3 is the residue of a saturated aliphatic monohydric alcohol. They may be obtained by bringing about a reaction by heat in the absence of an esterification catalyst between a saturated aliphatic dicarboxylic acid, an aromatic dicarboxylic acid, an alkylene glycol, and at least one saturated aliphatic monohydric alcohol, the molecular proportion of glycol being between 0.66 and 0.96 and the molecular proportion of monohydric alcohol being between 0.12 and 0.66 for each molecular proportion of total dicarboxylic acids. Either or both of the dicarboxylic acids can be used in the form of their anhydrides. The reaction can be carried out by heating the dicarboxylic acids the glycol and the monohydric alcohol in the absence of air, e.g. in a nitrogen atmosphere, and by bubbling nitrogen through the reaction mass, or the dicarboxylic acids and the glycol can first be heated together in the absence of air and the resulting acid glycol ester then heated with a monohydric alcohol. Specified glycols are 1 : 2 propylene glycol, ethylene glycol, and butylene glycol. Polyglycols may also be used. The dicarboxylic acids are preferably sebacic acid and phthalic acid and specified monohydric alcohols are 2-ethyl hexanol and 3,5,5-trimethyl hexanol. The reaction can be carried out at above 130 DEG C. and is preferably carried out at progressively increasing temperatures, e.g. up to 200-250 DEG C. It is preferred to carry out the reaction in the absence of a diluent. Examples are given for the production of complex esters from sebacic acid, phthalic anhydride, 2-ethyl hexanol, and 1,2-propylene glycol using various molecular proportions of the reactants to give different values of "n." A comparative example is also given for the preparation of a complex ester from sebacic acid (3 mols.), 2-ethylhexanol (0.9 mol.) and 1.2-propylene glycol (2.83 mols.). The products are stated to be useful as thickeners for synthetic diester lubricants (see Group III) and as plasticizers for thermoplastic materials especially polyvinyl chloride (see Group IV (a)).ALSO:Complex esters of the formula: R3OOCR1COO(R2OOCR1COO)nR3 wherein n is a number from 2 to 10, the R1's represent the residues of dicarboxylic acids at least one being saturated aliphatic and at least one being aromatic, R2 is the residue of an alkylene glycol, and R3 is the residue of a saturated aliphatic monohydric alcohol (see Group IV (b)) may be used as thickeners for synthetic diester lubricants, e.g. for those prepared from sebacic acid and 2-ethylhexanol or 3,5,5-trimethylhexanol, or for mixed esters of these two alcohols. A table is given to show the effect on the viscosity, A.S.T.M. slope, and pour point, of adding various proportions of complex esters of the above type derived from sebacic acid, phthalic anhydride, 1,2-propylene glycol and 2-ethyl-hexanol to di-2-ethyl-hexyl sebacate and comparative figures are also given to show the effect of adding to the same diester a complex ester derived from sebacic acid (3 mol) 2-ethylhexanol (0.9 mol.) and 1,2-propylene glycol (2.85 mol.). Other glycols and monohydric alcohols from which the aliphatic-aromatic complex ester may be derived are ethylene and butylene glycols, polyglycols and 3,5,5-trimethyl hexanol.ALSO:Polymers, e.g. polyvinyl chloride, are plasticized with complex esters of the formula R3OOCR1COO(R2OOCR1COO)nR3 wherein n is a number from 2 to 10, the R1's are residues of dicarboxylic acids, at least one being saturated aliphatic and at least one being aromatic, R2 is the residue of an alkylene glycol, and R3 is the residue of a saturated aliphatic monohydric alcohol (see Group IV (b)). In an example a plasticized composition is made by milling together polyvinyl chloride, a complex ester in which n is 4.3 and which is derived from sebacic acid, phthalic anhydride, 1,2-propylene glycol and 2-ethyl hexanol and a paste comprising white lead and dioctyl phthalate. Other glycols and monohydric alcohols from which the complex esters may be derived are ethylene- and butylene glycols, polyglycols and 3-, 5,5-trimethyl hexanol.