Patent GB-872200-A (GB)
Title: Improvements in or relating to the stabilisation of alcohols and their esterification
IPC: C08K5/10
Filed: 1953-11-11
Abstract: Polymeric materials such as vinyl chloride polymers and copolymers, polyvinyl acetate, acrylate and methacrylate resins, rubbers such as the emulsion copolymers of butadiene and styrene or acrylonitrile or copolymers of isobutylene with small amounts of a diene such as isoprene are plasticized with esters of crude C6-16 aliphatic alcohols containing as colour-forming impurities unsaturated compounds, aldehydes or compounds forming aldehydes during esterification of the alcohols, the esters being prepared and stabilized against colour formation by reacting the alcohol with a carboxylic acid or anhydride thereof in the presence of a composition consisting of a glycol diether of the general formula: R-O-(Y-O)n-R, wherein R is a C1-4 alkyl radical, Y is an alkylene radical containing 2-3 carbon atoms and n is an integer from 1 to 4, and not more than 50% by weight of an alkali metal borohydride of the general formula MB (X3)H wherein M represents an alkali metal and X represents hydrogen or an alkoxy, alkoxy or aliphatic carbonyloxy group containing 1-8 carbon atoms (see Group IV(b) ).  The ether may be present in amounts of 0,01%-1,0% and the borohydride in amounts of 0,0003%-0,03% by weight of the alcohol.  The alcohols may be those prepared by the oxo or aluminium alkyl synthesis.  Specified acids are phthalic, maleic, adipic, azelaic, sebacic and glycollic acids. Specifications 802,860 and 860,242 are referred to.ALSO:Aliphatic alcohols containing 6 to 16 carbon atoms in the molecule and contaminated with carbonyl and/or unsaturated compounds are stabilized against colour formation on esterification by mixing the alcohol with a composition consisting of at least 50% by weight of a glycol ether of the general formula R-O-(Y-O)n-R, wherein R is a C1-4 alkyl radical, Y is an alkylene radical containing 2-3 carbon atoms and n is an integer of from 1 to 4, and not more than 50% by weight of a metallic borohydride of the general formula MB(X3)H wherein M represents an alkali metal, and X represents hydrogen or an alkyl, alkoxy or aliphatic carbonyloxy group containing 1-8 carbon atoms. Suitably, the borohydride may amount to 0.003-0.03% by weight and the ether may amount to 0.01 to 1.0% by weight of the alcohol.  The carbonyl impurities are defined as aldehydic compounds or substances yielding aldehydic compounds during esterification of the alcohols. The alcohols may be those obtained by the oxo synthesis or aluminium alkyl method.  Esters may be prepared from the above defined crude alcohols by reacting the alcohol with a carboxylic acid or anhydride thereof in the presence of the above defined mixture of glycol diether and alkali metal borohydride.  The stabilizing mixture may be added to the alcohol immediately prior to or during the esterification reaction.  Esters of dicarboxylic acids are suitably prepared by reacting the acid or its anhydride with 2-4 moles of the alcohol in the absence of a catalyst at 125-250 DEG C. or in the presence of an acid catalyst at 100-200 DEG C. An inert atmosphere is preferably used.  Water entrainers may also be used and reaction may be effected under elevated pressure. Examples describe the reaction of phthalic anhydride with a C10 oxo alcohol using a stabilizing mixture of NaBH4 and the dimethyl ether of di- or triethylene glycol, in the presence of toluene as entrainer and sometimes of sulphuric or ptoluene sulphonic acid as catalyst.  The esters of maleic, adipic, azelaic, sebacic and glycollic acids are also mentioned. Specifications 802,860 and 860,242 are referred to.