Isoprene Isopropyl alcohol

Asymmetric telomerization of isoprene and methanol by using chiral phosphines, such as menthyldiphenylphosphine, gave an optical yield of 17.6%. The telomerization of methanol and isoprene using w-allylpalla-dium chloride and PBu3 in the presence of sodium methoxide in a mixed solvent of methanol and isopropyl alcohol at room temperature for 2 days produced l-methoxy-2,6-dimethyl-2,7-octadiene (89) (80%) and 1-meth-oxy-2,7-dimethyl-2,7-octadiene (91) (15%) (91). After 2 days, the reaction mixture was heated at 80°C for 8 hours, and 2,6-dimethyl-l,3,7-octatriene (88) (75%) and 2,7-dimethyl-1,3,7-octatriene (85) (14%) were obtained. Also, NiCl2(Bu3P)2 was used as a cocatalyst for the formation of 88. 

The results in Table VI were obtained by the reactions at 80°C with Pd(acac)2 using different ligands in a mixture of methanol and isopropyl alcohol. From these results, it seems likely that reaction temperature has large influence on the regiospecificity of the telomerization. As another example, a mixture of isomeric telomers was obtained by the reaction of methanol and isoprene at 100° (95). 

Terpenoid Synthesis from Isoprene.—Interest continues in new syntheses of iso-prene and its derivatives the dioxan (37) is obtained108 in good yield by the Prins reaction of methylallyl chloride with formaldehyde (cf. Vol. 5, p. 8) free-radical addition of isopropyl alcohol to vinyl acetate yields compound (38) which gives isoprene by acid-catalysed reaction over alumina.109 (Z)-2-Methylbut-2-en-l-ol and dimethylallyl alcohol are readily available from frans-crotyl alcohol.110... 

Isopentenyl pyrophophate, 1028—1030, 1033-1034, 1044 Isoprene, 383, 1026 Isoprene rule, 1028 Isoprenoid compounds. See Terpenes Isopropenyl group, 169—170 Isopropyl alcohol, 19, 128 industrial preparation of, 224 properties of, 581... 

Diisopropyl ether may be used in place of isopropyl alcohol. In that case, the reaction does not require addition of propylene because the olefin forms in situ. These catalysts are particularly effective in polymerizations of some conjugated dienes to very high molecular weight products. Styrene also polymerizes. Polymers of the dienes that form are high in transAA repeat units. Butadiene is polymerized by these catalysts much more rapidly than is isoprene. On the other hand, 2,3-dimethylbutadiene fails to polymerize. 

Exxon Chlorobutyl 1065 Exxon Chlorobutyl 1066, Exxon Chlorobutyl 1068. See Isobutylene/isoprene copolymer, chlorinated ExxonMobil IPA. See Isopropyl alcohol ExxonMobil MEK. See Methyl ethyl ketone Exxpar451. See Paraffins, normal C5-20 Exx-Print 176 D Exx-Print 283 D. See Petroleum distillates, hydrotreated light Exx-PrInt 287 D. See Paraffins, normal C5-20 Exx-PrInt 588 D. See Petroleum distillates, hydrotreated middle... 

Isobutyl alcohol Isobutylene/isoprene copolymer Isobutylene/MA copolymer Isodecyl benzoate Isoheptane Isophorone Isophorone diisocyanate Isopropanolamine p-lsopropoxy diphenylamine Isopropyl acetate Isopropyl alcohol Itaconic acid Japan (Rhus succedanea) wax Kerosene Lauralkonium chloride... 

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