Isopropenyl ethyl ketone

The method thus interconverts a,/ -unsaturated ketones. The method is also suitable for conversion of a ketone to an aldehyde, but an aldoxime cannot be employed since the resulting isoxazole is very unstable. Isopropenyl ethyl ketone (5) was converted by this procedure into 2-methylpentenc-2-al (9). 

Other uses include use as a reaction and extraction solvent in pharmaceutical production as an intermediate for the preparation of catalysts, antioxidants (qv), and perfumes and as a feedstock in the production of methyl isopropenyl ketone, 2,3-butanedione, and methyl ethyl ketone peroxide. Concern has also arisen at the large volume of exported MEK which has been covertly diverted and used to process cocaine in Latin American countries... 

Methyl Isopropenyl Ketone. Methyl isopropenyl ketone [814-78-8] (3-methyl-3-buten-2-one) is a colorless, lachrymatory Hquid, which like methyl vinyl ketone readily polymerizes on exposure to heat and light. Methyl isopropenyl ketone is produced by the condensation of methyl ethyl ketone and formaldehyde over an acid cation-exchange resin at 130°C and 1.5 MPa (218 psi) (274). Other methods are possible (275—280). Methyl isopropenyl ketone can be used as a comonomer which promotes photochemical degradation in polymeric materials. It is commercially available in North America (281). 

Newton and Strom, 1958). Similar radiolysis of isopropenyl acetate did not 5ueld acetic acid and its mass spectrum had only a weak signal at mje 61. The same authors suggested that the signal at mje 45, in the mass spectrum of isopropyl acetate, corresponded to the formation of acetaldehyde on radiolysis. Two rearranged ions in the mass spectrum of isopropenyl acetate, m/e 72 and mje 58, were noted to correspond to the formation of methyl ethyl ketone and acetone by radiolysis. 

The methylene group of methyl ethyl ketone is active in the condensation to give, upon pyrolysis, only methyl isopropenyl ketone (92%). Olefinic aldehydes, acids, esters, and nitro compounds have been prepared in a similar manner. The literature of the Mannich reaction has been reviewed. ... 

Preparation of Monomers. Methyl vinyl ketone (MVK) was obtained from Pfizer Chemical Division, New York, and distilled to remove the inhibitor. Methyl isopropenyl ketone (MIPK) was prepared by the aldol condensation of methyl ethyl ketone and formaldehyde, according to the method of Landau and Irany 0. The major impurity in this monomer is ethyl vinyl ketone (5. The monomer was redistilled before use. 3 Ethyl 3 buten 2 one (EB) was prepared by the aldol condensation of methyl propyl ketone and formaldehyde. Ethyl vinyl ketone (EVK) was prepared by a Grignard synthesis of the alcohol, followed by oxidation to the ketone. t-Butyl vinyl ketone (tBVK) was prepared from pinacolone and formaldehyde by the method of Cologne (9). Phenyl vinyl ketone (PVK) was prepared fay the dehydrochlorlnatlon of 0 cbloro propiophenone (Eastman Kodak). Phenyl isopropenyl ketone (PPK) was prepared by the Mannich reaction using propiophenone, formaldehyde and dimethylamine HCl. 

CO, CH4, CO2, acetone, ketene. ethene. propene. 1-butene, benzene, toluene, xylene, cydopentene, methyl ethyl ketone, diethyl ketone, methyl-n-propyl ketone, di-n-propyl ketone, methyl vinyl ketone, methyl Isopropenyl ketone, methyl isopropyl ketone, ethyl vinyl ketone, trace amounts of methyl-n-bulyl ketone, cyclopentanone, cydohexanone. acrolein, ethanal. butanal. chain fragments, some monomer CO. CH4, COj, ketene, 1-butene, propene, acetone, methyl ethyl ketone, methyl n-propyl ketone, 1,4-cyclohexadiene. toluene, l-methy. l.3-cydohexadlene, 2-hexanone, cydopentene, 1-methyl cydopentene. mesityl oxide, xylenes, benzene, ethene, cyclopentanone, 1.3-cyclopentad iene, diethyl ketone, short chain fragments, traces of monomer CO, CH4, COi, ketene, 1-butene, propene, acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl-n-propyl ketone, diethyl ketone, methyl propenyl ketone, 3-hexanone. toluene, 2-hexanone. 1,3-cydopentadiene, cyclopentanone, 2-melhylcydopenlanone, mesityl oxide, xylenes, benzene, propionaldehyde, acrolein, acetaldehyde ethene, short chain fragments, traces of monomer CO, COj, H2O, CH4. acetone, ketene, ethene, propylene, 1-butene, methyl vinyl ketone, benzene, acrylic add, toluene, xylene, short chain fragments such as dimer to octamer with unsaturated and anhydride functionalities... 

Methyl isopropenyl ketone was prepared from methyl ethyl ketone and formaldehyde 8) (boiling range 96.0-97.5°, 94 % ketone as methyl isopropenyl ketone). 

Ethyl methyl ketone (methyl ethyl ketone) CH3COC2H5 [1193] Methyl isopropenyl ketone, stabilised CH3COC3H7 [1245] Methyl propyl ketone CH3COC3H7 [1249]... 

Methyl isopropenyl ketone Methyl ethyl ketone + Formalin Rheinpreussen (1964)... 

Using an enzymatic diastereosdective acetylation process, the (5R,3J )-alcohol 54a was prepared from racemic 54 [107]. Lipase PS-30 effidendy catalyzed the acetylation of racemic 54 (4 g/L) to yield the (5i ,3S)-acetate 55 and the unreacted, desired (5P,31 )-alcohol 54a. A reaction yield of 49 M% and an ee of 98.5% was obtained for (5P,31 )-alcohol 54a when the reaction was conducted in toluene in the presence of isopropenyl acetate as an acyl donor. In methyl ethyl ketone at 50 g/L substrate concentration, a reaction yield of 46 M% and ee of 96% were obtained for (51 ,31 )-alcohol 54a [107]. 

Ethylene, butene-1, isobutene, acetylene, CO2, CH4, CO, acetone, isopropylaldehyde, methacrolein, butyraldehyde, methyl ethyl ketone, benzene (trace), methyl isopropyl ketones, methyl isopropenyl ketone, diethyl ketone, methyl n-propenyl ketone, cyclopentanone, methyl... 

Monomer, phthalic anhydride, diethylene glycol, C2H4, propylene, CO2 CO2, alkenes, CH4, CO, propanal methanol (major), acetone, 2-methyl propanal, methacrolein, butanal, methyl ethyl ketone, methyl isopropyl ketone, methyl isopropenyl ketone, methyl methacrylate (major), methyl prop-2-enyl ketone, toluene, di-isopropyl ketone, cyclopentanone, 2-methyl cyclopentanone, 2,5-dimethyl cyclopentanone, 2,5-di-methyl cyclopent-3-enone. Relative yields depend upon salt and copolymer composition... 

On distillation with a small proportion of iodine, oxalic acid, sulfuric acid, or other acidic catalysts., monomethylol methyl ethyl ketone is readily dehydrated to methyl isopropenyl ketone (b.p. 98 °C) which yields li -colored resins on poh merization and other resins by chemical reaction . ... 

At higher temperatures the mixture of 10 and methyl vinyl ketone yields the 1,4-carbocyclic compound as described previously. Methyl isopropenyl ketone (5), ethyl acetylacrylate (d), 2-cyclohexenone (21), and 1-acetyl-1-cyclohexene (22) also undergo this type of cyclization reaction with enamines at higher temperatures. This cycloalkylation reaction occurs with enamines made of strongly basic amines such as pyrrolidine, but the less reactive morpholine enamine combines with methyl vinyl ketone to give only a simple alkylated product (7). Chlorovinyl ketones yield pyrans when allowed to react with the enamines of either alicyclic ketones or aldehydes (23). 

Under comparable conditions the submitters found that the corresponding dihydropyran derivatives were similarly obtained by the condensation of acrolein with methyl vinyl ether in 80-81% yield, with ethyl vinyl ether (77-85% yield), with w-butyl vinyl ether (82% yield), with ethyl isopropenyl ether (50% yield), and with w-butyl cyclohexenyl ether (40% yield). Other <, /3-un-saturated carbonyl compounds that have thus been condensed with ethyl vinyl ether are crotonaldehyde (87% yield), meth-acrolein (40% yield), a-ethyh/3-n-propylacrolein (54% yield), cinnamaldehyde (60% yield), /3-furylacrolein (85% yield), methyl vinyl ketone (50% yield), benzalacetone (75% yield), and benzal-acetophenone (74% yield). 

Ethyl-isopropenyl- IV/2, 375 Ethenyl-isopropyl- Vl/ld, 147 f. Furan 2-Methyl-tetrahydro- IV/lh, 157 (Cycl.) IV/ld, 226 (Keton-Red.) VI/lb, 611 f. (Jeger-Reakt) VI/3, 529f. (Cyctokond.) Oxetan... 

Esters -> vinyl ethers. The original publication (8, 83-84) mentioned that ethyl acetate reacts with 1 to give ethyl isopropenyl ether. More recent work1 has shown that this conversion of esters to vinyl ethers is general and proceeds in high yields. The reaclion rate is dramatically increased by the presence of donor ligands (THF, C,11SN). The solvent is benzene or toluene. Ketone methylenation is possible, and actually Ihc rate is lour times that of ester methylenation. Isolated yields are cited in the examples. 

The isopropenyl acetate method yields, for example, 96 % of isomer B from ethyl methyl ketone, but 92% of isomer A from isobutyl methyl ketone. With acetic anhydride and p-toluenesulfonic acid 20-oxo steroids give the enol acetates B,707 but with isopropenyl acetate give the enol acetates A.708... 

The use of ethyl alcohol for the selective reduction of the carbonyl group in unsaturated aldehydes and ketones other than acrolein is illustrated in Table V. Here also, the data listed are the best obtained in a limited number of runs with each compound and do not necessarily represent optimum conditions. As previously stated, in the acrolein-allyl alcohol reaction a small amount of propyl alcohol is found in the products. This side reaction appears to be considerably more important with crotonaldehyde, since the C4 alcohol fraction here contained 27 % butyl alcohol. The relatively high conversion to saturated alcohol is believed to be due in part to unfavorable reaction conditions. With methacrolein and with methyl isopropenyl ketone the saturated alcohol amounted to 5 % of the imsaturated alcohol produced. 

The procedure involves reaction in acetic anhydride, or in another solvent, followed by the addition of acetic anhydride to decompose the intermediate complex. The procedure has been extensively examined in relation to the 5-methyl- and 4,5-dimethyl-substituted compounds derived from ethenyl methyl and methyl isopropenyl ketones and with mesityl oxide which gives the 3,3,5-trimethyl-substituted compounds. Amongest the phosphorus reactants, the trichloride itself and methyl- " , ethyl- " " and phenyl- phosphonous dichlorides have been employed, as have ethyl and phenyP dichlorophosphites, ROPCI2. The use of 2-thienylphosphonous dichloride to give 137 is recorded as is that of the unsaturated ketone 138 to give 139. A more novel conversion is that of 140 into 141 in 25% yield with a similar conversion (15%) being observed for cholest-4-en-3-one. ... 

Ammonium ceric nitrate dissolved in 8 4 1 methanol/ethyl methyl ketone/isopropenyl acetate, after 20-25 min at room temp. aq. NaHC03 added, and the mixture heated at 40° for ca. 45 min with vigorous stirring -> product. Y 78%. The method is highly regiospecific. F.e., also synthesis of y-ketoacetals with addition of 2 C-atoms using vinyl acetate, and with dimethyl malonate in place of ketones, s. E. Baciocchi et al.. Tetrahedron Letters 28, 5357-60 (1987). 

Enol esters such as vinyl or isopropenyl esters liberate unstable enols as coproducts, which tautomerize to give the corresponding aldehydes or ketones [151,152] (Scheme 3.4). Thus, the reaction becomes completely irreversible and this ensures that all the benefits with regard to a rapid reaction rate and a high selectivity are accrued. Acyl transfer using enol esters has been shown to be about only ten times slower than hydrolysis (in aqueous solution) and about 10-100 times faster than acyl-transfer reactions using activated esters. In contrast, when nonactivated esters such as ethyl acetate were used, reaction rates of about lO -lO of that of the hydrolytic reaction are observed (Table 3.5) [153]. 

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