Acetic Acid, Halogenated Derivatives

Abstract

The most important of the halogenated derivatives of acetic acid is chloroacetic acid, which has wide applications as an industrial chemical intermediate in the manufacture of cellulose ethers, herbicides, and thioglycolic acid. Most chloroacetic acid is produced by the chlorination of acetic acid. Chloroacetic acid is extremely corrosive and will cause serious chemical burns. It is readily absorbed through the skin; contamination of 5–10% of the skin is usually fatal. Sodium chloroacetate, C 2 H 2 ClO 2 Na, is produced by reaction of chloroacetic acid with sodium hydroxide or sodium carbonate. Dichloroacetic acid, C 2 H 2 Cl 2 O 2 , is a reactive intermediate in organic synthesis. It has been manufactured by the chlorination of acetic and chloroacetic acids and by other means. Trichloroacetic acid, C 2 HCl 3 O 2 , forms white deliquescent crystals. Sodium trichloroacetate, C 2 Cl 3 O 2 Na, is used as a herbicide. Chloroacetyl chloride (ClCH 2 COCl) is the corresponding acid chloride of chloroacetic acid, and is manufactured by reaction of chloroacetic acid with chlorinating agents. Much of the chloroacetyl chloride produced is used captively as a reactive intermediate. It is useful in many acylation reactions and in the production of adrenalin, diazepam, and chloroacetic anhydride. Two chloroacetate esters of industrial importance are methyl chloroacetate, C 3 H 5 ClO 2 , and ethyl chloroacetate, C 4 H 7 ClO 2 . Both are used as agricultural and pharmaceutical intermediates. Other derivatives are bromoacetic acid, dibromoacetic acid, tribromoacetic acid, iodoacetic acid, diiodoacetic acid, and triiodoacetic acid.

An Efficient Electrochemical Carboxylation of Polychloromethanes at Zinc Cathode in Acetonitrile

“…Therefore, we can surmise that in the absence of CO 2 , the reduction of CT leads to the formation of CF. Unlike other electrode materials, 25,37,38 zinc does not possess electrocatalytic properties for the reduction of these polychloromethanes. The peak potentials of the waves shift to negative potentials when the scan rate and the reactant concentration are increased.…”

“…Recently, some authors have carried out the electrocatalytic carboxylation of some aliphatic monohalides at a silver cathode. 24 In this work, we have carried out the synthesis of chloroacetic acids, which are less toxic and useful products in a wide range of applications, 25 by the electrochemical carboxylation of CT and CF using zinc as the cathode and sacrificial anodes in an undivided cell.…”

Conductometric simultaneous determination of acetic acid, monochloroacetic acid and trichloroacetic acid using orthogonal signal correction-partial least squares

“…The calibration set contains 16 standard solutions. The compositions of the calibration mixtures were selected according to (3,4) orthogonal design [30]. In Table 1, the compositions of the ternary mixtures used in the calibration matrices are summarized.…”

“…Three processes were used to manufacture trichloroacetic acid, exhaustive chlorination of acetic acid, oxidation of chloral (CCl 3 CHO) using H 2 O 2 and hydrolytic oxidation of perchloroethylene [4]. It has not been possible to estimate a global quantity of trichloroacetic acid manufactured but the estimated use in West Germany during the period "from the 1940s to 1990" was a total of about 30,000 t [5].…”

“…It has not been possible to estimate a global quantity of trichloroacetic acid manufactured but the estimated use in West Germany during the period "from the 1940s to 1990" was a total of about 30,000 t [5]. Apart from small quantities used as antiseptic, most of the manufactured material was used, in the form of sodium trichloroacetate, as herbicide [4]. Trichloroacetic acid is effective only in the control of monocotyledons, such as grasses.…”