Isobomyl acetate

Uses ndReactions. Camphene is used for preparing a number of fragrance compounds. Condensation with acids such as acetic, propionic, isobutyric, and isovaleric produce usehil isobomyl esters. Isobomyl acetate (41) has the greatest usage as a piae fragrance (81). The isobomyl esters of acryhc and methacrylic acids are also usehil ia preparing acryUc polymers. 

Isobomyl acetate [125-12-2] is also usehil ia produciag isobomeol (42) by saponiftcatioa. Dehydrogeaatioa or oxidatioa of isobomeol... 

Most synthetic camphor (43) is produced from camphene (13) made from a-piuene. The conversion to isobomyl acetate followed by saponification produces isobomeol (42) ia good yield. Although chemical oxidations of isobomeol with sulfuric/nitric acid mixtures, chromic acid, and others have been developed, catalytic dehydrogenation methods are more suitable on an iadustrial scale. A copper chromite catalyst is usually used to dehydrogenate isobomeol to camphor (171). Dehydrogenation has also been performed over catalysts such as ziac, iadium, gallium, and thallium (172). 

Isobomyl acetate, 31, 41 Isobutyl benzoate, 53 Isobutyl benzyl carbonate, 49 Isobutyl phenyl acetate, 53... 

In view of the feet that complete removal of water vapor cannot be readily achieved, we prepared water-free bulk and silica-supported zirconium sulfate. The bulk anhydrous Zr(S04)2 was obtained by reaction of zirconium tetrachloride with oleum [1]. The silica-supported zirconium sul te resulted from deposition-precipitation of zirconium hydroxide on silica, calcination at 723 K and subsequent reaction with gaseous sulfur trioxide. The catalytic activity of the sul ted zirconia s was measured in the gas-phase /rora-alkylation of benzene (1) with diethylbenzene (2) to ethylbenzene (3, reaction 1) [8,9] and the liquid-phase hydro-acyloxy-addition reaction of acetic acid (4) and camphene (5) to isobomyl acetate (6, reaction 2) [8,10]. With the /roras-alkylation we used an amorphous silica-aliunina catalyst as a reference. 

Fig. 5. Course of the reaction to isobomyl acetate (6) by the hydro-acyloxy-addition of 0.70 mol acetic acid (4) to 0.70 mol camphene (5) at 338 K (stirred tank reactor, N2 atmosphere). O 2.5 g %O IZxO ll Si02 without H2O and 2.5 g S03/Zr02/Si02 and 320 ml (17.78 mmol) H2O.

Camphor is produced by fractional distillation and crystallization of camphor oil or, synthetically, by dehydrogenation of isoborneol (from isobomyl acetate, see p. 76) over a copper catalyst. 

Isobomyl acetate is used in large amounts for perfuming soap, bath products, and air fresheners. However, the major use of isobomyl acetate is as an intermediate in the production of camphor. 

Isobomeol to Camphor. Nitric add has been widely used in the production of synthetic camphor from turpentine. The commonly accepted general practice for this manufacture (the one adapted by Gubehnann fw use in this country) involves the following steps (1) distillation of turpentine to obtain pinene, (2) saturation with HCl gas to obtain bomyl chloride, (3) hydrolyzing this to obtain camphene, (4) esterifying camphene to isobomyl acetate, (5) saponification to isobomeol, and (6) oxidation to camphor. 

Isoamyl salicylate Isobomeol Isobomyl acetate Isobomyl formate Jsobomyl propionate... 

Myrcenol Myrcenyl acetate Piperonyl acetone Prenyl benzoate fragrance, antiseptics Isobomyl acetate fragrance, aromatherapy Cedanwood oil fragrance, artificial jasmine Benzyl acetate fragrance, artificial lavandin Prenyl acetate fragrance, bath preps. 

Fir (Abies sibirica) needle oil Isobomyl acetate fragrance, beauty care Amyl benzoate y-Bisabolene Butyl isohexanoate Cyclamen homoaldehyde trans-4-Decenal... 

Addition of acids, such as acetic, propionic, isobutyric, and isovaleric, produces useful isobomyl esters, the most important of which is isobomyl acetate [125-12-2] (117) (131). Isobornyl acetate possesses a fruity and woody odor and its perfumery use runs into thousands of tonnes per annum. The isobomyl esters of acrylic and methacryUc acids are also useful in preparing acrylic polymers. Similarly, addition of alcohols and glycols to camphene catalyzed by strong acids such as Amberlyst 15 ion-exchange resin produces useful camphane ethers (118) (132). 

Saponification of isobomyl acetate produces isobomeol exo -1,7,7-trimethylbicyclo [2.2.1]heptan-2-ol [124-76-5]) (119), which can be oxidized or dehydrogenated to give camphor (120). 

Most synthetic camphor is produced from a-pinene (20) via camphene (27), as shown in Fig. 8.24. Addition of acetic acid to camphene gives isobomyl acetate (117), which is saponified to produce isobomeol (119) in good yield. Catalytic dehydrogenation of iso-borneol then gives camphor. Catalysts include copper chromite (319) or metals, such as zinc, indium, gallium, and thallium (320). 

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