Patent GB-946603-A (GB)
Title: Polynuclear phenolic antioxidants
IPC: C07F9/16
Filed: 1961-07-10
Abstract: The invention comprises a polynuclear phenol containing a hydrocarbon group having one or two benzene rings, the latter being substituted with one or more hydroxyl groups (a) and two or more 3,5 - dialkyl - 4- hydroxybenzyl groups (b) so that not more than three (a) and not more than three (b) groups are bound to each benzene ring and at least one of the alkyl groups of each hydroxybenzyl group is branched on the alpha-carbon atom; but polynuclear phenols claimed in Specification 892,261 are disclaimed.  Specific compounds claimed are 2,4,6-tri (3,5-di-t-butyl-4-hydroxybenzyl) phenol; 3,31, 5,51-tetra (3,5-di-t - aryl - 4 - hydroxybenzyl)-4, 41-dihydroxy-biphenol and 2,21-bis [3,5-di-(3,5-di-t-butyl-4-hydroxybenzyl) - 4 - hydroxphenyl] propane, but other compounds including those containing a naphthalene ring, are described, The compounds of the invention are prepared by reacting the appropriate phenol not substituted by groups (b) but having at least two replaceable hydrogen atoms on the benzene ring(s), with a 3,5-dialkyl-4-hydroxybenzyl alcohol having at least one alpha branched alkyl group, or an alkyl ether thereof with not more than four carbon atoms in the alkoxy group, in an inert solvent in presence of sulphuric acid or a Friedel-Crafts catalyst.  The compounds of the invention may be employed as inhibitors in monomers such as methyl ethyl and 2-ethylhexyl acrylates, methyl and ethyl methacrylates and acrylonitrile.ALSO:Polynuclear phenols wherein one or two benzene rings are substituted with at least one hydroxyl group and at least two 3,5-dialkyl-4-hydroxybenzyl groups (see Division C2), optionally together with an organic sulphur compound described below, are used in minor amount to stabilize organic compounds normally subject to oxidative deterioration such as poly-alphaolefins (e.g. polystyrene, polyethylene, polypropylene or ethylene/propylene copolymer) and natural or synthetic rubbers such as SBR, polybutadiene or polyisoprene.  Organic sulphur compounds are (1) mono, di or polysulphides, specifically dilaurylthiodipropionate, didodecyldisulphide, dodecylcetylsulphide, dicetylsulphide, di-eicosyl-sulphide, thiurandisulphide and its tetraalkyl derivatives; (2) those of formula <F\1> in which M is a Group II metal and R is a C1- 6 hydrocarbon group; (3) tri- C6- 20 - alkyl tri-thiophosphites; (4) polymers such as those containing the units -R1-O-R1-S-, -R1-O-R2-O-R1-S- or -R1(OH)-S-.  In examples, polypropylene is stabilized by addition of 2,4-di(3,5-di-t-butyl-4-hydroxybenzyl phenol, 2,6-di(3,5 di - t - butyl - 4 - hydroxybenzyl) - 4 - t - butylphenol or 2,4,6 - tri(3,5 - di - t - butyl - 4 - hydroxybenzyl)phenol.ALSO:Polynuclear phenols wherein one or two benzene rings are substituted with at least one hydroxyl group and at least two 3,5-dialkyl-4-hydroxybenzyl groups (see Division C2), optionally together with an organic sulphur compound described below, are used in minor amount to stabilize organic compounds normally subject to oxidative deterioration, e.g. a fuel oil such as kerosene, gasoline or furnace oil, a lubricating oil or grease, or a polymerizable liquid monomer such as vinylbenzenes including styrene, vinyl toluene and divinyl benzene.  Organic sulphur compounds are (1) mono, di or polysulphides, specifically dilaurylthiodipropionate, didodecyldisulphide, dodecylcetylsulphide, dicetylsulphide, di-eicosylsulphide, thiuramdisulphide and its tetraalkyl derivatives; (2) those of formula <FORM:0946603/C3/1> in which M is a Group II metal and R is a C1-6 hydrocarbon group; (3) tri-C6-20-alkyl trithiophosphites; (4) polymers such as those containing the units -R1-O-R1-S-, -R1-O-R2-O-R1-S- or -R1(OH)-S-. In examples, a white mineral oil and safflower oil are stabilized by addition of 2,4,6-tri-(3,5-di-t-butyl - 4 - hydroxybenzyl) phenol, or 2,2-bis-[3,5 - di - (3,5 - di - t - butyl - 4 - hydroxybenzyl)-4 - hydroxy phenyl]propane; or 2,4,6-tri-(3,5-di - t - butyl - 4 - hydroxybenzyl) - 3,5 - dimethylphenol in the case of the mineral oil.ALSO:Polynuclear phenols wherein one or two benzene rings are substituted with at least one hydroxyl group and at least two 3,5-dialkyl-4-hydroxylbenzyl groups (see Division C2), optionally together with an organic sulphur compound described below, are used in minor amounts to stabilize organic compounds normally subject to oxidative deterioration.  Organic sulphur compounds are (1) mono, di or polysulphides, specifically dilaurylthiodipropionate, didodecyldisulphide, dodecylcetylsulphide, dicetylsulphide, di-isooxylsulphide, thiureadisulphide, and its tetraalkyl derivatives; (2) those of formula <FORM:0946603/B1-B2/1> in which N is a Group II metal and R is a C1-6 hydrocarbon group; (3) tri-C6-20-alkyl trithiophosphites; (4) polymers such as those containing the units -R1-O-R1-S-, -R1-O-R2-O-R1 -S-or -R1-(OH)-S-.ALSO:Oxidative deterioration in fatty oils, gums, agar and gelatine is prevented by incorporation of polynuclear phenols wherein one or two benzine rings are substituted with at least one hydroxyl group and at least two 3,5-dialkyl-4 hydroxybenzyl groups. With the substituted poly-nuclear phenols may be used (i) mono-, di-or poly-sulphides, specifically dilaurylthiodipropionate, didodecyldisulphide, dodecylcetyl disulphide, dodecylcetylsulphide, dicetylsulphide, dieicosylsulphide, thiuramdisulphide and its tetraalkyl derivatives (ii) compounds of formula M(S-CS-NR2)2 wherein M is a Group II metal and R is a C1-6 hydrocarbon group (iii) tri-C6-20 alkyl trithiophosphites or (iv) polymers containing the units -R1-O-R1-S-, -R1-O-R2-O-R1-S- or -R1(OH)-S-.  Specification 892,261 is referred to.