Page 22 - Academic Press Encyclopedia of Physical Science and Technology 3rd Organic Chemistry

P1: GLQ Revised Pages
Encyclopedia of Physical Science and Technology EN001F-4 May 7, 2001 16:19

74 Acetylene

FIGURE 7 Linalool and dehydrolinalool from acetylene–acetone (Roche, BASF). Process conditions (average process yields under
formulas): (1,5) catalytic ethynylation in polar solvents using KOH or sodium under pressure (t = 30–50 C); (2,6) partial hydrogenation
◦
using a palladium catalyst modified (t = 25–45 C); (3) reaction of methylbutenol with diketene (DK)
◦
C O
CH 2
H 2 C CO
◦
(t = 20–40 C): catalyst, tertiary amine; MBe, acetocetate ester not isolated [see (4)]; (4) allylic rearrangement and cleavage of product
(3) using aluminum isopropoxide under fractionation column.

FIGURE 8 Processes for the production of citral. Roche: Catalysts, siloxyvanadium moieties; excess tris(trimethylsiloxy) vanadium oxide;
◦
conditions, liquid phase, 2–20 hr at 125–140 C; conversions 72–77%; yield 96%. Rhone Poulenc (Rhodia): Catalysts, vanadium alkoxides,
excess cyclohexyl orthovanadate; conditions, liquid phase, 15 min to 4 hr at 125–160 C; conversions 37–40%; yield 77–82%; Oxidative
◦
Dehydrogenation of Geraniol (SCM-Glidden).
CH 3
−H

(CH 3 ) 2 C CH(CH 2 )2 C CHCH 2 OH Citral H 2 O
O
Possibly vapor-phase process; copper-type catalyst; estimated yield 70–80%.