Isophorone synthesis

Isophorone usually contains 2—5% of the isomer P-isophorone [471-01-2] (3,5,5-trimethyl-3-cyclohexen-l-one). The term a-isophorone is sometimes used ia referring to the a,P-unsaturated ketone, whereas P-isophorone connotes the unconjugated derivative. P-lsophorone (bp 186°C) is lower boiling than isophorone and can be converted to isophorone by distilling at reduced pressure ia the presence of -toluenesulfonic acid (188). Isophorone can be converted to P-isophorone by treatment with adipic acid (189) or H on(Ill) acetylacetoate (190). P-lsophorone can also be prepared from 4-bromoisophorone by reduction with chromous acetate (191). P-lsophorone can be used as an iatermediate ia the synthesis of carotenoids (192). 

The catalytic oxidation of isophorone (259—261) or P-isophorone (262,263) to ketoisophorone [1125-21 -9] (2,6,6-trimethyl-2-cyclohexen-l,4-dione) has been reported. Ketoisophorone is a building block for synthesis in terpene chemistry and for producing compounds of the vitamin A and E series. 

Tab. 5.31 Synthesis of diaryl-a-tetralones from isophorone and chalcone under MW + PTC conditions.

One of the most thoroughly investigated aldol condensations is the selfcondensation of acetone. This is an important industrial reaction for the production of diacetone alcohol (DA) (Scheme 11), which is valuable as a chloride-free solvent and an intermediate in the synthesis of industrially important products such as mesityl oxide (MO), isophorone, methyl isobutyl ketone, and 3,5-xylenol. The reaction is exothermic, with the yield of DA decreasing with increasing reaction temperature it is usually performed with NaOH or KOH as a basic catalyst 118). 

Isophorone is a solvent for a large number of natural and synthetic polymers, resins, waxes, fats, and oils. Specifically, it is used as a solvent for concentrated vinyl chloride/acetate-based coating systems for metal cans, other metal paints, nitrocellulose finishes, printing inks for plastics, some herbicide and pesticide formulations, and adhesives for plastics, poly(vinyl) chloride and polystyrene materials (Papa and Sherman 1981). Isophorone also is an intermediate in the synthesis of 3, 5-xylenol, 3, 3, 5-trimethylcyclohexanol (Papa and Sherman 1981), and plant growth retardants (Haruta et al. 1974). Of the total production, 45-65% is used in vinyl coatings and inks, 15-25% in agricultural formulations, 15-30% in miscellaneous uses and exports, and 10% as a chemical intermediate (CMA 1981). 

Kidney tumors caused by several different compounds, including 1,4-dichlorobenzene, isophorone, and unleaded petrol, have been found to be both sex dependent and species dependent. Thus, only male rats suffer from oc2-p-globulin nephropathy and renal tubular adenocarcinoma as a result of the accumulation of a compound-protein complex in the epithelial cells of renal proximal tubules (see chap. 6). The synthesis of the protein involved, a2-[i-globulin, is under androgenic control in the male rat. 

M. Hennig, K. Puntener, and M. Scalone, Synthesis of ( <)- and (S)-4-hydroxy-isophorone by ruthenium-catalyzed asymmetric transfer of hydrogenation of ketoisophorone, Tetrahedron Asymm. 2000, 11, 1849-1858. 

Figure 6.6 Evolution of tan 8 during polyurethane synthesis at 110°C, at different angular frequencies,

For racemic (3RS,3 RS)-astaxanthine (58), an industrially practicable synthesis was developed which uses oxo-isophorone (55) as the starting compound, and yields... 

A similar [4 + 2] cycloaddition across the a, -positions has been observed in the reaction of isophorone dienamines with electrophilic alkenes (vide infra), and a similar ring opening has been postulated in the reaction of methyl vinyl ketone with dienamines in aprotic media (Section VII.C). Confirmatory evidence for the role of the C-3 methyl group in the above reaction was obtained from reaction of 8-methyl-A 1,8a-2-octalone dienamine with methyl acrylate only the /Talkylated product was obtained in protic and aprotic solvents14. The reaction of dienamines with electrophilic alkenes is discussed further in the section on carbocyclic synthesis (Section VII.C). 

Barrere and Landfester [184] prepared a hybrid miniemulsion in which isophorone diisocyanate was condensation polymerized with dodecanediol to form polyurethane at the same time that the polystyrene or polyBA was free radical polymerized. Unlike previous work, the polyurethane was not prepared in organic solvent in advance. Therefore, in this one-pot synthesis, polyaddition and free radical polymerization both take place in the same particle. HD was used as the costabihzer. After miniemulsification, the polycondensation was allowed to take place, and then a free radical initiator was added to polymerize the styrenic or acrylic monomer. Molecular weight distributions were bimodal the PU had a substantially lower molecular weight than the polyacrylate. Neither intra- nor interparticle phase separation could be detected by TEM the particles appeared to be homogeneous. No measurements of grafting were made, but since there was no unsaturation in the PU, none was expected. 

A technical synthesis of (4i ,6/ )-4-hydroxy-2,2,6-trimethylcyclohexanone (85) starting from the readily available oxo-isophorone (86) has been described. (85) is an ideal precursor for the synthesis of optically active hydroxylated carotenoids (e.g. zeaxanthin). Chirality was introduced at C-6 (C-3, carotene numbering) by a stereoselective reduction of the double bond by baker s yeast." ... 

Acetone is used as a solvent for cellulose acetate, nitrocellulose and acetylene as a raw material for the chemical synthesis of such products as ketones, acetic anhydride, methyl methacrylate, bisphenol-A, diacetone alcohol, methyl isobutyl ketone, isophorone, etc. 

Good catalytic properties have also been reported by Teissier and Kervenal [34] for the synthesis of isophorone on an hydrotalcite first calcined then rehydrated. The superiority of the rehydrated solid in the experiment is apparent from the observation that the reaction performed in a batch reactor at 473 K reaches about... 

A new process for synthesis of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (IPDA) has been investigated. The reaction was performed in two steps. In the first step bis (3-cyano-3,5,5 trimethylcyclohexylidene) azine (IPNA) was synthesized from 3-cyano-3,5,5 trimethyl- 1 oxo cyclohexane (IPN) and hydrazine hydrate in solvent. The reaction yield was nearly quantitative. In the second step the azine (IPNA) was hydrogenated under mild conditions on a Raney nickel or cobalt catalyst in the presence of a small amount of ammonia. Isophorone diamine (IPDA) was obtained at high yields (90-95 %). But the main interest of a such process is to minimize the production of byproducts (aminoalcohol, azabicyclic compound, secondary amine) and to use less severe pressure conditions than those generally employed. 

At the present time isophorone diamine (IPDA) is experiencing a good expansion in its traditional markets such as polyurethanes, paints and varnishes. For this reason a real interest has been shown in the synthesis of IPDA. Until now, this compound was synthesized by aminoreduction of isophoronenitrile (IPN). 

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