GB854976A - Alkylated indanols - Google Patents

Abstract

The deterioration and ageing of natural and synthetic rubbers is retarded by the incorporation therein of an alkylated indanol of the general formula: <FORM:0854976/IV(a)/1> wherein R represents a monovalent hydrocarbon radical, R1 and R11 each represent a hydrogen atom or monovalent hydrocarbon radical having from 1 to 12 carbon atoms, m is either 0 or 1, n is either 1 or 2, but the sum of m and n is not greater than 2, and the <FORM:0854976/IV(a)/2> radical is attached in the 5- and/or 7 positions when the OH group is in the 4- position, and in the 4- and/or 6- positions when the OH group is in the 5-position. Data are given which show the efficiency of (1) 6-t-butylated-5-indanol (2) 5-t-butylated-4-indanol and 5, 7-di-t-butylated -4-indanol (3) 6-octylated-5-indanol, and (4) 6-alpha-methylbenzylated-5-indanol as flex-cracking-resistors and heat-stabilizers in vulcanized rubber products, as demonstrated by incorporating each alkylated indanol in a standard natural rubber tread stock recipe, curing in a steam press, and then testing. The tread stock recipe also contained carbon black, zinc oxide, stearic acid, sulphur, and bis (2-benzothiazyl)-disulphide. Synthetic rubbers may also be treated, and reference is made to polymers of butadiene, isoprene, piperylene, chloroprene, and cyanobutadiene as well as copolymers of any of these conjugated dienes with each other and/or with styrene, chlorostyrene, isobutylene, acrylonitrile, methacrylonitrile, acrylic and methacrylic acids, alkyl acrylates and methacrylates, vinylidene chloride, and vinyl pyridines. For the preparation of the alkylated indanols-see Group IV(b).ALSO:Alkylated indanols of the general formula: <FORM:0854976/IV(b)/1> are prepared by the reaction between an indanol or a substituted indanol and a mono-olefin in which the double bond is positioned between the first and second carbon atoms of the hydrocarbon chain. The alkylating group, derived from the olefin molecule, is attached in the 5- and/or 7-positions when the OH group is in the 4-position, and in the 4- and/or 6-positions when the OH group is in the 5-position. In the above formula, R represents a monovalent hydrocarbon radical, R1 and R11 each represent a hydrogen atom or monovalent hydrocarbon radical having from 1 to 12 carbon atoms, m is either 0 or 1, n is either 1 or 2, and the sum of m and n is not greater than 2. The alkylated indanols are effective as deterioration-retarders for rubber products (see Group IV(a)). Olefins which may be used as alkylating agents are ethylene, propylene, diisopropylene, the butylenes, diisobutylene, styrene, and alpha-methyl styrene. The reaction between the olefin and the indanol is carried out in the presence of a catalyst such as sulphuric acid, p-toluene sulphonic acid, boron trifluoride, and activated clays. The preferred catalyst is an acid activated clay containing more than 50% of aluminium silicate, and has a particle size of less than 0,05 m.m. In Example 1, a mixture of 5-indanol, benzene and acid activated clay is warmed to 55 DEG C. and isobutylene is introduced, beneath the surface of the liquid with agitation, over a period of about 3 1/2 hours. The mixture is then filtered, and the filtrate is distilled to remove benzene. The residue is distilled under reduced pressure to give the product, viz.: 6-t-butylated-5-indanol. In Example 2, isobutylene is reacted with 4-indanol to give 5-t-butylated-4-indanol and 5,7-di-t-butylated-4-indanol. Example 3 illustrates the production of 6-octylated-5-indanol by reacting 5-indanol with diisosobutylene using sulphuric acid as catalyst. Example 4 illustrates the preparation of 6-alpha-methylbenzylated-5-indanol by reacting styrene with 5-indanol. Examples 5 to 12 relate to the preparation of the following compounds: 5,7-diethyl-4-indanol; 4,6-dibutyl-5-indanol; 1,1-dimethyl-6-ethyl-5-indanol; 1,3-dibutyl-7-butyl-4-indanol; p 1,1-dimethyl-3-propyl-4,6-dibutyl-5-indanol; 1,1,3-trimethyl-6-butyl-5-indanol; 1,3-dimethyl-5-alpha-methylbenzyl-4-indanol; and 1,1,3-trimethyl-7-butyl-5-alpha-methylbenzyl-4-indanol.