Patent GB-743212-A (GB)
Title: Tetrahydro-dicyclopentadiene carboxylic acids and derivatives thereof
IPC: C07C61/135
Filed: 1953-04-14
Abstract: The invention comprises tetrahydro - a  - dicyclo pentadiene mono-carboxylic acids, their salts and alkyl esters having the general formula <FORM:0743212/IV(a)/1> wherein the group C10H13 comprises two doubly joined saturated five-membered rings not containing any carbon atoms common to both rings, M is a metal, hydrogen or an alkyl radical, R and R1 are hydrogen or alkyl groups, R1 and COOM are attached to the same five-membered ring and R and R1 are attached to different five-membered rings.  The acids are prepared by catalytically hydrogenating a dimer of cyclopentadiene and/or an alkyl cyclopentadiene to form dihydro-dicyclopentadiene or a mono- or di-alkyl dihydro-dicyclopentadiene, reacting the dihydro product with carbon monoxide and more than one molar equivalent of an aliphatic monohydric alcohol in the presence of a cobalt-containing catalyst at a temperature of 100 DEG  to 200 DEG  C. and a pressure of 2500 to 4000 p.s.i.g. to produce a saturated monocarboxylic ester and hydrolysing this ester to the acid.  The resulting acids may be esterified with other alcohols or glycols or converted into salts. The hydrogenation of the dienic dimer may be effected at temperatures up to 100 DEG  C. and pressures of up to 1000 p.s.i.g. in the presence of such catalysts as Raney nickel, nickel on kieselguhr or noble metal oxide catalysts, e.g. platinum oxide.  The product is preferably distilled to recover the pure dihydro-dimer.  The alcohol used in the ester-oxonation step may be methanol, ethanol, isopropanol, iso octyl alcohol or decanol.  The catalyst may be cobalt metal, cobalt carbonyl or a cobalt salt of an organic acid soluble in one of the reactants, e.g. the acetate, oleate, naphthenate or the cobalt salt of the acids of the invention.  The product comprises the alkyl esters of the two isomeric tetrahydro dicyclopentadiene carboxylic acids. The esters may be hydrolysed with dilute acid preferably in the presence of a surface-tension reducing agent or saponified followed by acidification.  The free acids form oil- and hydrocarbon-soluble salts with all metals, e.g. cobalt, lead, manganese, copper and zinc, suitable for use in fungicides, mildew preventatives, paints (see Group III) and in the treatment of leather and textiles (see Group VIII).  The esters of the acids may be used as plasticizers and synthetic lubricants.  They are capable of rendering basic dyes oil- and hydrocarbon-soluble. According to the examples (1) a crude dicyclopentadiene is cracked by distillation to remove methyl cyclopentadiene and the purified cyclopentadiene is dimerized; the dimer is hydrogenated in ethanol using PtO3 as catalyst; the resulting dihydro-a -dicyclopentadiene is recovered and reacted in methanol with CO in an autoclave at 150 DEG  C. using cobalt metal catalyst so yielding the methyl esters of the two tetrahydro-a -dicyclo pentadiene carboxylic acids; (2) these esters are saponified with alcoholic potash and acidified to yield the free acids which are converted into (3) the copper salts, (4) the cobalt salts and (5) the manganese salts; (7) a commercial dicyclopentadiene copolymer (75 per cent cyclopentadiene, 15 per cent methyl cyclo pentadiene) is hydrogenated in the presence of Raney nickel and the dihydro co-dimer is ester-oxonated as in (1) and the resulting ester saponified to methyl tetrahydro dicyclo pentadiene carboxylic acid; (8) methyl cyclopentadiene is dimerized, the dimer hydrogenated and then ester-oxonated as in (1) yielding after saponification dimethyl-tetrahydro dicyclopentadiene carboxylic acid.  Specification 651,853 is referred to.ALSO:Heavy metal salts of tetra - hydro -   - dicyclo pentadiene mono - carboxylic acids having the general formula:- <FORM:0743212/III/1> wherein the group C10H13 comprises two doubly joined saturated five-membered rings not containing any carbon atoms common to both rings and R and R1 are hydrogen or alkyl groups, R1 and COOH being attached to the same five-membered ring and R and R1 attached to different five-membered rings, may be used as driers. The cobalt, lead and manganese salts are mentioned.  An example compares the drying effects of the cobalt and manganese salts of tetra-hydro- -dicyclo pentadiene carboxylic acid with commercial cobalt and manganese driers on linseed oil and a synthetic drying oil based on poly-butadiene. The preparation of the salts is given (see Group IV(b)). Specification 651,853 [Group IV(b)] is referred to.