Patent GB-732913-A (GB)
Title: Multiple esters
Inventor: PALMER RICHARD GILBERT
IPC: C07C69/34
Filed: 1952-04-01
Abstract: Multiple esters which serve as plasticizers e.g. for polyvinyl chloride, are made by esterifying an acid X(COOH)2 with a large stoichiometrical excess of a glycol HO[(CH2)n11O]n1(CH2)n11OH at elevated temperatures and in the substantial absence of an esterification catalyst and esterifying the di-hydroxy compound so formed with an acid R.COOH where X is a polymethylene chain of 4-8 C atoms, R a straight chain alkyl radicle of 1-17 C atoms, n1 0 or 1-25 and n11 2-6.  Adipic, pimelic, suberic, azelaic and sebacic acids are specified di-acids.  Ethylene, tri-, tetra-, penta- and hexa-methylene, di-ethylene and bis-trimethylene glycols are specified glycols.  Acetic, propionic, butyric, valeric, caproic, caprylic, capric, lauric, myristic, palmitic and stearic acids are specified monoacids, those containing 6-12 C atoms, especially an even number of C atoms, being preferred.  Mixtures of acids may be used or the anhydrides used instead of the acids.  Details of the esterifiction are given in Group IV (b).  In examples: (1) adipic and (2) sebacic acids are esterified with diethylene glycol and their esters respectively esterified with a mixture of C6-12 carboxylic acids of average molecular weight 152 and caprylic acid, the final products being used as plasticizers for polyvinyl chloride.  In the Provisional Specification o-phthalic acid is also specified as a di-acid.ALSO:Multiple esters are made by esterifying an acid of formula X(COOH)2 with a large stoichiometrical excess of a di-primary glycol of formula <FORM:0732913/IV (b)/1> at elevated temperatures and in the substantial absence of an esterification catalyst and esterifying the di-hydroxy compound so formed with an acid of formula R.COOH where X is a polymethylene chain of 4-8 carbon atoms, R a straight chain alkyl radicle of 1-17 atoms, n1 0 or 1-25 and n11 2-6. Adipic, pimelic, suberic, azelaic and sebacic acids are specified di-acids.  Ethylene, tri-, tetra-, penta- and hexa-methylene, di-ethylene and bis-trimethylene glycols are specified.  Acetic, propionic, butyric, valeric, caproic, caprylic, capric, lauric, myristic, palmitic and stearic acids are specified mono-acids, those containing 6-12 C atoms, especially an even number of C atoms, being preferred.  Mixtures of acids may be used or their anhydrides.  The first stage is effected rapidly to minimize production of polyesters of formula <FORM:0732913/IV (b)/2> , where n is 1-26, y is 2 or a greater integer and R as above, at high temperatures, e.g. 200-250 DEG  C. in the absence of temperature depressants and water entrainers.  Excess glycol is recovered from the first stage and recycled.  The second stage is effected under conventional esterification conditions, e.g. at 100-160 DEG  C. in the presence of sulphuric acid and a water entrainer, e.g. benzene.  The products are plasticizers, e.g. for P.V.C. and are substitutes for mineral oil lubricants.  In examples: (1) adipic and (2) sebacic acids are esterified with diethylene glycol and their products respectively esterified with a mixture of C6-12 carboxylic acids of average molecular weight 152 and caprylic acid.  In the Provisional Specification o-phthalic acid is also specified.