Patent GB-778924-A (GB)
Title: Synthetic glycols and their preparation
IPC: C07C33/035
Filed: 1954-12-08
Abstract: The invention comprises a mixture of unsaturated glycols of the formula: <FORM:0778924/IV(b)/1> wherein n and m are each 0 or 1, R, R1, R2 and R3 are alkyl, aryl or alkaryl groups or hydrogen atoms and R4 is an alkenyl group; and their preparation by dimerizing a conjugated diolefine in the presence of finely dispersed sodium or potassium in an active aliphatic ether diluent and preferably in presence of at least one dimerization activator, immediately reacting the resulting organometallic diene intermediate with an epoxide compound and hydrolysing the metal derivatives of the glycols thus obtained.  The invention also comprises the mixtures of C12 and C14 diolefinic aliphatic glycols obtained by the reaction of butadiene, sodium and, respectively, ethylene and propylene oxides, the mixtures of saturated glycols obtained by hydrogenation of these mixtures, a mixture of C12 saturated glycols containing as two of the major components 3-ethyl-1,10-decanediol and 3,6-diethyl-1,8-octanediol, a mixture of C14 saturated glycols consisting essentially of 4,7-diethyl - 2,9 - decanediol, 4 - ethyl - 2,11-dodecanediol and 2,13-tetradecanediol, and each of the aforementioned saturated diols as a new compound.  Other diolefine starting materials referred to include isoprene, dimethylbutadiene and the methyl-1,3-pentadienes, and these are conveniently reacted with a dispersion of 1 equivalent or a slight molecular excess of the alkali metal in an inert hydrocarbon or ether below 0 DEG  C. and preferably at -20 DEG  C. to -50 DEG  C.  Aliphatic ether diluents specified for this reaction are any aliphatic mono ether having a methoxy group or mixtures thereof and acyclic and cyclic polyethers derived by replacing all of the hydroxyl hydrogen atoms of a polyhydric alcohol by alkyl groups.  The dimerization activator is either a polycyclic aromatic compound such as naphthalene, phenanthrene, diphenyl, the terphenyls, dinaphthyl or tetraphenylethylene used in an amount of 0.1 to 10 weight per cent based on the amount of diolefines undergoing dimerization, or a solid, friable attrition agent such as an alkali metal salt, sand, diatomaceous earth, "Cellite" (Registered Trade Mark), zircon, rutile or graphite, or a mixture of these.  Other epoxides for use in the second reaction stage include the butylene oxides, styrene oxide and the epoxide derivatives of dienes, and this stage is preferably carried out at below 20 DEG  C. and advantageously in the range -50 DEG  C. to 0 DEG  C., at least two equivalents of epoxide compound being required for each molecule of dimetallic dimer.  In examples: (1) a dispersion of sodium in iso-octane is contacted with butadiene in the presence of dimethyl ether and terphenyl at about -23 DEG  C., gaseous ethylene oxide is then admitted at -30 DEG  C., the reaction product is treated with methanol and then water, the organic layer is separated and the inert solvents removed therefrom, the residual oil is hydrogenated over a platinum oxide catalyst, the resulting oil of saturated glycols is acetylated, a portion of the resulting C12 diacetates is fractionally distilled, and the fractions are saponified giving 3,6-diethyl-1,8-octanediol, 3-ethyl-1,10-decane diol and 1,12-dodecanediol; (2) propylene oxide replaces the ethylene oxide of (1), the products isolated being 4,7-diethyl-2,9-decanediol, 4 - ethyl - 2,11 - dodecanediol and 2,13-tetradecanediol; (3) isoprene, sodium and ethylene oxide are reacted substantially as in (1), and the products present in the final hydrogenated product are 4,9-, 5,8- and 4,8-dimethyl-1,12-dodecanediols and 3-isopropyl-7 and 6-methyl-1,10-decanediols.  In a similar manner disodio-octadienes and styrene oxide yield 1,10-diphenyl - 3 - ethyldecanediol - 1,10 and 1,8-diphenyl - 3,6 - diethyloctanediol - 1,8; and the phenyl group may be replaced by a p-tolyl radical.