Patent GB-932818-A (GB)
Title: Novel antioxidant 3,5-dialkyl-4-hydroxybenzyl ethers and their preparation
IPC: C09K15/08
Filed: 1961-10-02
Abstract: Gasoline, motor oils, lubricating oils, diesel oils, turbine oils, gear oils, transformer oils, domestic heating oils, cutting oils, brake fluids, drying oils, paints, and fixed oils are stabilized against oxidation by 3,5-dialkyl-4-hydroxybenzyl ethers of the formula:-  <FORM:0932818/III/1> wherein n is 0 and m is 1, n is 1 and m is an integer from 1 to 5 inclusive, each R is an alkyl group containing from 3 to 8 carbon atoms, branched on the alpha carbon atom, R1 is (1) an unsubstituted aliphatic hydrocarbon group containing at least m+1 carbon atoms, connected to m+1 hydroxybenzyloxy groups, or (2) a phenylene group, or (3) a polyalkyleneoxy group of the formula -R2-(OR2)pin which each R2 represents an alkylene group containing from two to six carbon atoms, and p is a whole positive number from 1 to 5, inclusive, with the proviso that, when R1 represents said polyalkyleneoxy or phenylene group, m is 1.  The compositions may contain as a second stabilizer, an organic sulphur compound of the type R1-Sx-R2 where x is a whole number and R1 and R2 are similar or dissimilar organic groups bound to Sx by carbon atoms, or an organic sulphur compound of the formula R1(R2)N-C(=S)-S-M-S-C(=S)-N(R2)R1, wherein M is a metal of Group II of the Periodic System and R1 and R2 are hydrocarbon groups having from 1 to 6 carbon atoms, or a trialkyltrithiophosphite having 6 to 20 carbon atoms, or polymeric products such as polyalkoxyalkylsulphides, polyalkoxyalkoxyalkylsulphides or polyhydroxyalkylsulphides. Specifications 847,248 and 893,896 are referred to.ALSO:Polystyrene, natural and synthetic rubber, for instance, styrene-butadiene rubber and polyisoprene are stabilized against oxidation by 3,5-dialkyl-4-hydroxybenzyl ethers of the formula:- <FORM:0932818/IV(a)/1> wherein n is 0 and m is 1, n is 1 and m is an integer from 1 to 5 inclusive, each R is an alkyl group containing from 3 to 8 carbon atoms, branched on the alpha carbon atom, R1 is (1) an unsubstituted aliphatic hydrocarbon group containing at least m+1 carbon atoms, connected to m+1 hydroxybenzyloxy groups, or (2) a phenylene group, or (3) a polyalkyleneoxy group of the formula -R2-(OR2)p-in which each R2 represents an alkylene group containing from two to six carbon atoms, and p is a whole positive number from 1 to 5, inclusive, with the proviso that, when R1 represents said polyalkyleneoxy or phenylene group, m is 1.  The compositions may contain as a second stabilizer, an organic sulphur compound of the type R1-Sx-R2 where \s3 is a whole number and R1 and R2 are similar or dissimilar organic groups bound to SX by carbon atoms, or an organic sulphur compound of the formula R1(R2)N-C(=S)-S-M-S-C(=S)-N(R2)R1, wherein M is a metal of Group II of the Periodic System and R1 and R2 are hydrocarbon groups having from 1 to 6 carbon atoms, or a trialkyltrithiophosphite having 6 to 20 carbon atoms, or polymeric products such as polyalkoxyalkyl sulphides, polyalkoxyalkoxyalkyl sulphides or polyhydroxyalkyl sulphides. Specifications 847,824 and 893,896 are referred to.ALSO:The invention comprises a 3,5-dialkyl-4-hydroxybenzyl ether having the general formula <FORM:0932818/IV(a)/1> in which n = 0, m = 1, or n = 1 and m represents an integer from 1 to 5 inclusive, each R is an alkyl group containing from 3 to 8 carbon atoms, branched on the alpha carbon atom, R1 is (1) an unsubstituted aliphatic hydrocarbon group containing at least m + 1 carbon atoms connected to m + 1 hydroxybenzyloxy groups, or (2) a phenylene group, or (3) a polyalkyleneoxy group of the formula -R2-(O-R2)pin which each R2 represents an alkylene group containing from two to six carbon atoms, and p is a whole positive number from 1 to 5, inclusive, with the proviso that, when R1 represents said polyalkyleneoxy or phenylene group, m is 1.  The novel ethers may be made by reacting the corresponding 3,5-dialkyl-4-hydroxybenzyl alcohol with itself or with either an unsubstituted aliphatic polyhydroxy alcohol having not more than 6 hydroxyl groups, or a dihydroxybenzene, or a polyalkylene-oxyglycol of the formula HO-R2-(OR2)p-OH in which R2 is an alkylene group containing from 2 to 6 carbon atoms and p is an integer from 1 to 5 inclusive, in the presence of an acid catalyst, e.g. sulphuric acid, hydrogen bromide or boron trifluoride.  The reaction temperature is preferably within the range from 10 DEG  to 100 DEG C.  Lists of suitable starting materials are given.  The ethers and polyethers represent a new class of antioxidants which may be used to stabilize fatty acids.  Detailed examples describe the preparation of tri(3,5-di-tert. butyl-4-hydroxybenzyl) glyceryl ether, bis(3,5-di-tert. butyl-4-hydroxybenzyl) ether, di(3,5-di-tert. butyl-4-hydroxybenzyl) phenylene dioxy ether.  Specifications 847,824 and 893,896 are referred to.ALSO:Foods are stabilized against oxidation by 3,5-dialkyl-4-hydroxybenzyl ethers of the formula <FORM:0932818/VI/1> wherein n is 0 and m is 1, n is 1 and m is an integer from 1 to 5 inclusive, each R is an alkyl group containing from 3 to 8 carbon atoms, branched on the alpha carbon atom, R1 is (1) an unsubstituted aliphatic hydrocarbon group containing at least m+1 carbon atoms, connected to m+1 hydroxybenzyloxy groups, or (2) a phenylene group, or (3) a polyalkyleneoxy group of the formula -R2-(OR2)pin which each R2 represents an alkylene group containing from two to six carbon atoms, and p is a whole positive number from 1 to 5, inclusive, with the proviso that, when R1 represents said polyalkyleneoxy or phenylene group, m is 1.  The compositions may contain as a second stabilizer, an organic sulphur compound of the type R1-Sx-R2 where x is a whole number and R1 and R2 are similar or dissimilar organic groups bound to Sx by carbon atoms, or an organic sulphur compound of the formula R1(R2)N-C(=S)-S-M-S-C(=S)-N(R2)R1, wherein M is a metal of Group II of the Periodic System and R1 and R2 are hydrocarbon groups having from 1 to 6 carbon atoms, or a trialkyltrithiophosphite having 6 to 20 carbon atoms, or polymeric products such as polyalkoxyalkylsulphides, polyalkoxyalkoxyalkylsulphides or polyhydroxyalkylsulphides. Specifications 847,824 and 893,896 are referred to.