Chlorination of acetophenone

According to Beilstein (VII, 283) trichloroacetophenone is obtained by chlorination of acetophenone at elevated temperatures.1 However, at 60° less than 1 per cent of trichloroacetophenone is formed. 

Dichloroacetophenone has been prepared by chlorination of acetophenone with and without aluminum chloride 1 by action of dichloroacetyl chloride upon benzene and aluminum chloride 1 by action of hypochlorous acid upon phenylacetylene 2 by heating trichloromethylphenylcarbinol 3 and by chlorination of phenylacetylene in alcohol.4... 

Cadmium chloride as catalyst in conversion of dipotassium 1,8-naph-thalenedicarboxylate to 2,6-naph-thalenedicarboxylic acid, 72 Chlorination, nuclear, aluminum chloride as catalyst for, 9 of pyruvic acid by sulfuryl chloride, 54 Chlorine in oxidation of methyl disulfide to methanesulfinyl chloride, 62 3-Chloroacetophenone from aluminum chloride catalyzed chlorination of acetophenone, 10... 

Repeat Problem 4.31 for the chlorination of acetophenone, and explain why the product is m-chloroacetophenone. 

In 194l the CWS erected a modern plant with a rated capacity of one ton of CN per day. This became the sole CWS plant in 1943 when the old 1922 plant was dismantled. The manufacture of chloroacetophenone involved three steps the production of monochloroacetic acid, the chlorination of the acid to chloroacetyl chloride, and condensation of chloro-acetyl chloride with benzene in the presence of a catalyst. The CWS was aware of another method that was potentially capable of being adapted to large-scale manufacture, the chlorination of acetophenone. If this could be... 

Explain why bromination and chlorination of acetophenone, PhC(=0)CH3, occur at the same rate. Solution... 

A three-step process involving the oxidation of acetophenone, hydrogenation of the ketone to a-phenylethanol, and dehydration of the alcohol to styrene was practiced commercially by Union Carbide (59) until the early 1960s. Other technologies considered during the infancy of the styrene industry include side-chain chlorination of ethylbenzene followed by dehydrochlotination or followed by hydrolysis and dehydration. 

The above procedure2 is modeled after that described for the nitrosation of arylethyl ketones.4-5 w-Chloroisonitroso-acetophenone has been prepared by the chlorination of isonitro-... 

In the flask are placed 240 g. (2 moles) of acetophenone and 1 1. of glacial acetic acid. The thermometer is adjusted so that it extends considerably below the surface of the solution, and chlorine is admitted at such a rate that the temperature does not exceed 60° (Note 1). Chlorination is continued until an excess of the halogen has been absorbed. This requires about five hours completion of the reaction is indicated by the development of a yellow color. The reaction mixture is poured over 6 1. of crushed ice in a 2-gal. jar. The mixture is stirred several times (Note 2) and allowed to stand until the ice has melted. The dichloroacetophenone, which separates as a heavy lachrymatory oil, is removed. The yield is 340-370 g. (90-97 per cent of the theoretical amount). This product, containing only a few per cent of water and acetic acid, is pure enough for the preparation of mandelic acid. It may be purified by adding about 100 cc. of benzene, removing the... 

Most of the phenol used in the United States is made by the oxidation of cumene, yielding acetone as a byproduct. The first stqn in the reaction yields cumene hydroperoxide, which decomposes with dilute sulfuric acid to the primary products, plus acetophenone and phenyl dimethyl carbinol. Other processes include sulfonation, chlorination of benzene, and oxidation of benzene. The compound is purified by rectification. 

It is prepared by the action of chlorine on acetophenone according to Korten and Scholl s method. ... 

Pearson27 was to manipulate orientation in various ways to obtain any isomer desired. An example cited on 1, 32-33 is the meru-bromination of acetophenone, described by Pearson as a swamping catalyst effect. In the bromination of a phenol, para substitution ordinarily predominates over ortho substitution, but considerable increase in the proportion of ortho isomer can be achieved by operating at — 70° in the presence of a strongly basic aliphatic amine.28 The best procedure was to add bromine to a cold solution of f-butylamine in toluene, cool to about — 7(P, and add a phenol dropwise over a short period of time. By this procedure, phenol was converted by 1 equivalent of bromine into 2-bromophenol in 60% yield and by 2 equivalents of bromine into 2,6-dibromophenol in 87% yield. Tertiary amines such as DABCO and triethylamine serve also for enhanced o-bromination of phenols. Chlorination under the same conditions gave a mixture of o- and p-chlorophenols in the ratio 2 1. 

Thorough kinetics studies of the chlorination of aliphatic, alicyclic, and arylalkyl ketones with CBT were carried out by Indian workers (82PIA921). Kinetic measurements were performed using aqueous acetic acid and the addition of HC104 and NaCl. In the presence of mineral acid the reaction is first order in ketone and acid and zero order in CBT. A large kinetic isotopic effect was observed (for acetone kHlkD = 6.6). Addition of chloride ion causes some changes in the reaction order they become first order in CBT, 0.6 in ketone, and 0.2 in chloride ion. The rate constant for chlorination of substituted acetophenones correlate with a constants for substituents in the aryl ring (p is -0.57). On the basis of these data the mechanism in the absence and in the presence of chloride ion was developed. 

Kinetic studies of oxidation of acetophenone oximes with CBT in aqueous acetic acid were carried out (86MI1). The main reaction products are acetophenones. The scheme of oxidation, complying with the kinetic data and the effects of the acidity of the medium and the addition of chloride ions, proposes that the attack of positively charged chlorine on the oxime group nitrogen is the rate-limiting stage, followed by the fast transformation of the carbocation formed (Scheme 105). 

Cktoro het4MUx TIrichtoroisocyanuric acid, activated by cibcrate. ii an efficient tca nt for a-chlorination of ketones at the moie substituted position. It can be used to convert acetophenone into -chloro-, . and o.o,a> trichloFoacetophcnone (81% yield). 

Likewise, the series of fluorous (dichloroiodo)arenes 127-129 and alkyl iodine(III) dichlorides 130-132 (Figure 5.7) have been prepared in 71-98% yields by reactions of the corresponding fluorous iodides with chlorine [69]. These compounds are effective reagents for the chlorination of alkenes (e.g., cyclooctene) and aromatic compounds (e.g., anisole, 4-rcrt-butylphenol and acetophenone). The organic chlorinated products and fluorous iodide co-products are easily separated by organic/fluorous liquid/liquid biphasic workups. The fluorous iodides can be recovered in 90-97% yields and reoxidized with chlorine [69]. 

Reagents and Equipment. To a 5-mL conical vial containing a magnetic spin vane and equipped with an air condenser, add 6 (xL (63 mg, 51 mmol) of acetophenone and 2.1 mL of household bleach (NaOQ, 5% available chlorine) ( -). 

Aldehydes and ketones with at least one a-hydrogen react at the a-carbon with bromine and chlorine to form a-haloaldehydes and a-haloketones as illustrated by bromination of acetophenone. 

Preparation by chlorination of 2-hydroxy-5-methoxy-acetophenone with N-chlorosuccinimide in acetic acid containing magnesium acetate at r.t. for 24 h under nidogen atmosphere (80%) [2559,2560],... 

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