Patent GB-928169-A (GB)
Title: Trinuclear phenol antioxidants
Inventor: GODIN GEORGE WILLIAM
IPC: C07C39/16
Filed: 1960-12-02
Abstract: Polyethylene is stabilized against oxidation by the incorporation therein of a compound of the formula:  <FORM:0928169/IV(a)/1> where R4 represents the same or different alkyl, cycloalkyl or aralkyl groups and X represents an alkyl, aralkyl or cycloalkyl group containing from 9 to 12 carbon atoms, or an alkoxy group containing from 10 to 12 carbon atoms.  In Example (6) a linear polyethylene is stabilized with 0,05% by weight of 2,6-bis-(2-hydroxy-3,5-dimethylbenzyl)-4-methyl phenol.ALSO:The invention comprises compounds of the formula: <FORM:0928169/IV(a)/1> where R4 represents the same or different alkyl, cycloalkyl or aralkyl groups and X represents an alkyl, aralkyl or cycloalkyl group containing from 9 to 12 carbon atoms or an alkoxy group containing from 10 to 12 carbon atoms, and a process for preparing compounds of the formula:  <FORM:0928169/IV(a)/2> which comprises condensing, in the presence of a minor proportion (i.e. less than 50% by weight of the total reaction mixture) of a substance providing divalent metal cations, a substituted phenol of the formula:  <FORM:0928169/IV(a)/3> with a substituted hydroxymethyl phenol of the formula: <FORM:0928169/IV(a)/4> where R represents the same or different alkyl, cycloalkyl or aralkyl groups, R1 represents an alkyl, cycloalkyl, aralkyl group or hydrogen atom, R3 represents an alkoxyl group containing from 10 to 12 carbon atoms, an alkyl, cycloalkyl or aralkyl group and R2 represents an alkyl, cycloalkyl, aralkyl or methylol group and when R1 is a hydrogen atom R2 is an alkyl, cycloalkyl or aralkyl group otherwise R2 is a methylol group only. The condensation may, for example, be carried out in the presence of a compound of Mn, Zn, Cd, Mg or Co which provides divalent metal cations or a mixture of such compounds.  The preferred metal compound is zinc acetate. Preferably the proportion of substance employed is that sufficient to provide from 0.1% to 5% by weight of the cations based on the total weight of the phenols used.  The substituted hydroxymethyl phenol may be produced by reacting the corresponding substituted phenol with formaldehyde in the presence of an alkaline condensing agent, e.g. NaOH, to produce the salt of the hydroxymethyl phenol, the phenol itself being liberated by acidification.  It is preferred however to carry out the condensation of the phenol with formaldehyde consecutively followed by the condensation of the substituted hydroxymethyl phenol with the substituted phenol in the same reactor employing the same catalyst.  In the examples the following compounds are prepared: (1) 2,6-bis(2-hydroxy-3,5-dimethylbenzyl)-4-methyl phenol; (2) 2,6- (bis(2- hydroxy- 3,5- dimethylbenzyl)- 4-cumyl phenol; (3) 2,6-bis(2-hydroxy-3,5-dimethylbenzyl)-4-dodecyl phenol; (4) 2,6-bis(2-hydroxy-3-tert. butyl-5-methylbenzyl)-4-cumyl phenol and (5) 2,6-bis(2-hydroxy-3,5-dimethylbenzyl)-4-octyl phenol. Di-2-(ethylhexyl) phthalate may be stabilised against oxidation by incorporation therein of 2,6-bis(2- hydroxy- 3,5-dimethylbenzyl)-4-dodecyl phenol or 2,6-bis(2-hydroxy-3-tert. butyl- 5-methylbenzyl)- 4-cumyl phenol.  Equal parts by weight of a composition of 2,6-bis(2- hydroxy-3,5- dimethylbenzyl)-4-cumyl phenol with zinc pentamethylene dithio carbamate or dilauryl thiodipropionate may be used as an antioxidant.