Patent GB-893896-A (GB)
Title: A process for the preparation of alkyl-substituted hydroxybenzyl alcohols
IPC: C07C39/11
Filed: 1960-07-28
Abstract: Gasoline is stabilized by incorporating therein 3, 5-di-tert-butyl-4-hydroxybenzyl alcohol (see Group IV(b))ALSO:A process for the preparation of an alkyl substituted hydroxybenzyl alcohol comprises reacting an alkyl substituted phenol having a replaceable hydrogen atom on at least one of the ortho ring carbon atoms or on the para ring carbon atom, with formaldehyde in the presence of a secondary or tertiary alcohol and a catalytic amount of a base miscible with the reaction system at a temperature below 25 DEG C.  Esters are produced by reacting the alkyl substituted hydroxybenzyl alcohols produced by the above process having a hydroxycarbyl substituent ortho to the phenolic hydroxy group with a mono- or polycarboxylic acid.  Ethers are produced by condensing the alkyl substituted hydroxybenzyl alcohols, produced by the above process, in the presence of an alkyl alcohol having not more than six carbon atoms, a polyhydric alcohol or an alkylene oxide.  The invention also comprises an ester of an alkyl substituted hydroxybenzyl alcohol having a hydrocarbyl substituent ortho to the phenolic hydroxy group, e.g. 3,5-ditert.butyl-4-hydroxybenzyl palmitate, di-(3,5-diisopropyl-4-hydroxybenzyl)phthalate and 3-methyl-5-tertiarybutyl-4-hydroxybenzyl methacrylate.  Preferably the preparation of the alkyl substituted hydroxybenzyl alcohol is carried out in a reaction system containing not more than 5% of water.  The formaldehyde may be employed as gas or may be generated from formaldehyde polymers.  Basic catalysts specified include alkali metal alkoxides and alcoholates and quaternary ammonium hydroxides. The process may be carried out continuously. The examples relate to the preparation of 3,5-dimethyl, di-tert.butyl- and diisopropyl-4-hydroxybenzyl alcohols and 2- hydroxy-3-tert.butyl-5-methyl, and 2-hydroxy-3-methyl-5-tertiary-butyl benzyl alcohols.  A list of alkylated phenols for use as starting materials is furnished. 2,6-Dialkyl-4-methyl phenols, e.g. 2,6-ditert.-4-methyl-and 2-tert.butyl-4,6-dimethyl phenols, are produced by catalytic reduction of the corresponding 3,5-dialkyl-4-hydroxybenzyl alcohols. Methylene bis(2,6-dialkylphenol) compounds are produced by condensing two molecules of 3,5-dialkyl-4-hydroxybenzyl alcohols in the presence of an alkanol and a basic or acidic catalyst.  2, 6 - Di (3, 5 - dialkyl - 4 - hydroxybenzyl) - 4 - alkyl phenols are produced by condensing 2 moles of an appropriate hydroxybenzyl alcohol with 1 mol of a monoalkyl phenol in the presence of a basic catalyst 2,6-di(3,5-ditert.-butyl - 4 - hydroxybenzyl) - 4 - methyl phenol is obtained by condensing 3, 5 - ditert.butyl - 4 - hydroxybenzyl alcohol with p-cresol in the presence of caustic soda. 3,31,5,51-Tetraalkyl substituted 4,41-dihydroxydiphenylmethanes are produced by contacting 3,5-dialkyl-4-hydroxybenzyl alcohols with 2,6-dialkyl phenols in basic or acidic alcoholic solution.  2, - (3, 5 - Dialkyl - 4 - hydroxybenzyl) - 4, 6 - dialkyl phenols are produced by condensing the benzyl alcohols with 2,4-dialkyl phenols in the presence of acidic or basic condensation catalysts and solvents.  Substituted benzylethers are prepared by condensing the 3,5-dialkyl-4-hydroxybenzyl alcohols with alcohols, representative of those mentioned being methanol, ethylene and neopentyl glycols and glycerol.  3, 5 - Ditert.butyl - 4 - hydroxybenzyl palmitate is obtained by esterification of palmitic acid with the corresponding alcohol. The oleate and stearate are similarly prepared.  The esterification of the benzyl alcohols with phthalic, isophthalic, terephthalic, acrylic and methacrylic acids is also described.