Methyl-heptenone

Methyl-heptenone from citral (by boiling with solution of carbonate of potassium) 67 5° (4 mm.) 0-8590 1-45611 49-424 49-438... 

Methyl-heptenol is an alcohol with a delicate rose odour, of the formula CgHjgO. It occurs in Mexican and Cayeme linaloe oil, and is-prepared by reducing methyl-heptenone, and has the following characters —... 

Methyl-heptenone, CgH, 0, occurs in various essential oils, especially lemon-grass oil, in which it is associated with, and difi cult to separate from, the aldehyde citral. 

It forms a semi-carbazone melting at 136° to 138°, which can be obtained as follows Ten c.c. of methyl-heptenone are dissolved in 20 c.c. of facial acetic acid, and a mixture of 10 grams of semi-carbazide hydrochloride and 15 grams of sodium acetate dissolved in 20 c.c. of water is added. After half an hour the semi-carbazone is precipitated by the addition of water, and recrystalUsed from dilute alcohol. 

Methyl-heptenone also forms a bromine derivative which is well suited for the identification of the ketone. This body, which has the formula CgHjjBrgO. OH, melts at 98° to 99°, and is obtained as follows Three grams of methyl-heptenone are mixed with a solution containing 3 grams of caustic soda, 12 grams of bromine, and 100 c c. of water. After a time an oily substance is deposited, which is extracted with ether. The solvent is evaporated, and the residue, redissolved in ether, is treated with animal charcoal and filtered. On slow evaporation the product is obtained in well-defined crystals. 

Methyl-heptenone combines with sodium bisulphite. On reduction by means of sodium and alcohol, it forms the corresponding alcohol, methyl-heptenol, CgHj OH, which has the following characters —... 

Ciamician and Silber have found that. light has a marked effect on methyl-heptenone. The ketone was kept in a glass flask, exposed to the light for five months, the flask being exhausted of air, which was replaced by oxygen. When the seal was broken, the contents of the flask were found to be at reduced pressure, and the oxygen was mainly converted into carbon dioxide. 

The methyl-heptenone was decomposed, with the formation of acetone, a ketonic glycol, CgH gOg, and a hydroxydiketone, CgH 402-... 

Methyl heptenone dissolved in 75% alcohol Is reduced with activated aluminum in the presence of methylamine to give isometheptene. 

Geraniol and citronellal (50-80%), terpenes, methyl-heptenone, bomeol Mineral oils, fatty oils... 

Worldwide, in excess of five million pounds of linalool and its esters are manufactured for fragrances by five different processes. Three of them involve methylheptenone as an intermediate. The other two are based on turpentine. The three routes to methyl-heptenone are outlined in Figure 13. 

An important intermediate for synthetic p-ionone (36) is the C8 building block methyl heptenone (37). In addition to the synthesis shown above, two further processes are known for its industrial production. In the process of Rhodia INC 36), the starting material is isoprene, and methyl heptenone (37) is obtained via prenyl chloride. At BASF, methyl heptenone (37) is produced, for economic reasons, in the form of its double bond isomer (37 a) by thermal condensation of isobutylene, formaldehyde and acetone 37) (see page 13). By suitable choice of the reaction conditions, various side-reactions, such as the Cannizzarro reaction of formaldehyde, the oligomerization of isobutene and aldol condensation between formaldehyde and acetone, can largely be suppressed. 

SYNS FEMA No. 2707 5-HEPTEN-2-ONE, 6-METHYL- METHYL HEPTENONE... 

METHYL-3-HEPTANONE (OSHA) see ODIOOO METHYL HEPTENON E see MKKOOO... 

D.33) 5-Hepten-2-one, 6-methyl-, 6-methylhept-5-en-2-one, 2-methyl-2-hepten-6-one, methyl heptenone [110-93-0] FEMA 2707... 

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