Chlorohydrins preparation

Chlorohydrins, preparation from a-chloro acids. 66, 161 2-Chloromethoxybenzene Anisole, o-chloro- Benzene, 1-chloro-2-methoxy- (766-51-8), 67, 222... 

Chloromethylation.1 Chloromethyl methyl ether has been generally used for electrophilic aromatic chloromethylation, but it is highly toxic and now considered a carcinogen. Chloromethylation can be effected by use of a trimethylsilyl ether (1) of a chlorohydrin prepared as shown from trioxane and chlorotrimethylsilane in the presence of stannic chloride in chloroform. This reagent, generated in situ, is effective for chloromethylation of styrene in the presence of SnCl4 any excess is easily decomposed by hydrolysis. Bromomethylation is possible by replacement of ClSi(CH3)3 by BrSi(CH3)3. 

CH3 CH0H CH20H, a colourless, almost odourless liquid. It has a sweet taste, but is more acrid than ethylene glycol b.p. 187. Manufactured by heating propylene chlorohydrin with a solution of NaHCO under pressure. It closely resembles dihydroxyethane in its properties, but is less toxic. Forms mono-and di-esters and ethers. Used as an anti-freeze and in the preparation of perfumes and flavouring extracts, as a solvent and in... 

Glycerol (i-monochlorohydrin, 2-chloru-trimelhylene glycol, 1,3-dihydroxy-2-chlorO propane, CH2 0H CHC1 CH2 0H. Colourless liquid b.p. 146"C/18mm. It is obtained in small amounts in the preparation of the x-chlorohydrin. 

Methyl acrylate is usually prepared from ethylene chlorohydrin thus ... 

HVP products prepared by hydrolysis with HCl contain varying amounts of glycerol chlorohydrins, such as 3-chloro-l,2-propanediol [96-24-2] and l,3-dichloro-2-propanol [96-23-1J, depending on reaction conditions and Hpid contents of the starting material (135). As a result of their toxicides, regulating agencies in many countnes have restncted the contents of these compounds in food. 

Mixtures of glycerol with other substances are often named as if they were derivatives of glycerol eg, boroglycetides (also called glyceryl borates) are mixtures of boric acid and glycerol. Derivatives, such as acetals, ketals, chlorohydrins, and ethers, can be prepared but are not made commercially, with the exception of polyglycerols. 

Propylene oxide [75-56-9] (methyloxirane, 1,2-epoxypropane) is a significant organic chemical used primarily as a reaction intermediate for production of polyether polyols, propylene glycol, alkanolamines (qv), glycol ethers, and many other useful products (see Glycols). Propylene oxide was first prepared in 1861 by Oser and first polymerized by Levene and Walti in 1927 (1). Propylene oxide is manufactured by two basic processes the traditional chlorohydrin process (see Chlorohydrins) and the hydroperoxide process, where either / fZ-butanol (see Butyl alcohols) or styrene (qv) is a co-product. Research continues in an effort to develop a direct oxidation process to be used commercially. 

Some substituted alkyl hydrogen sulfates are readily prepared. Eor example, 2-chloroethyl hydrogen sulfate [36168-93-1] is obtained by treating ethylene chlorohydrin with sulfuhc acid or amidosulfuhc acid. Heating hydroxy sulfates of amino alcohols produces the corresponding sulfuhc monoester... 

Where X is Br or Q, the free acids may be obtained by acidification of the alkaline solution, but where X is I, the acids must be isolated as salts to avoid reduction of the arsonic acids by HI. Rather than using alkyl haUdes, alkyl or dialkyl sulfates or alkyl arenesulfonates can be used. Primary alkyl haUdes react rapidly and smoothly, secondary haUdes react only slowly, whereas tertiary haUdes do not give arsonic acids. AHyl haUdes undergo the Meyer reaction, but vinyl hahdes do not. Substituted alkyl haUdes can be used eg, ethylene chlorohydrin gives 2-hydroxyethylarsonic acid [65423-87-2], C2H2ASO4. Arsinic acids, R2AsO(OH), are also readily prepared by substituting an alkaU metal arsonite, RAs(OM)2, for sodium arsenite ... 

Butylene Oxide. Butylene oxides are prepared on a small scale by Dow by chlorohydrin technology. There appears to be no technical reason why they could not be prepared by the propylene oxide Oxirane process (see Chlorohydrins). 

Organic solutions of HOCl can be prepared in near quantitative yield (98—99%) by extraction of CU -containing aqueous solutions of HOCl with polar solvents such as ketones, nitriles, and esters (131). These organic solutions of HOCl have been used to prepare chlorohydrins (132) and are especially useful for preparation of water-insoluble chlorohydrins. Hypochlorous acid in methyl ethyl ketone has also been used to prepare Ca(OCl)2, by reaction with CaO or Ca(OH)2 (133), and hydrazine by reaction with NH3 (134). 

A chlorohydrin has been defined (1) as a compound containing both chloio and hydroxyl radicals, and chlorohydrins have been described as compounds having the chloro and the hydroxyl groups on adjacent carbon atoms (2). Common usage of the term appHes to aUphatic compounds and does not include aromatic compounds. Chlorohydrins are most easily prepared by the reaction of an alkene with chlorine and water, though other methods of preparation ate possible. The principal use of chlorohydrins has been as intermediates in the production of various oxitane compounds through dehydrochlorination. 

Esterification. Chlorohydrins can react with salts of carboxyUc acids to form esters. For example, 2-hydroxyethyl benzoate [134-11-2] was prepared ia 92% yield by heating sodium benzoate [532-32-1] with an excess of ethylene chlorohydrin ia the presence of a small amount of diethylamine... 

QuaterniZation. Choline chloride [67-48-1] was prepared ia nearly quantitative yield by the reaction of trimethylamine [121-44-8] with ethylene chlorohydrin at 90—105°C and 981—1471 kPa (10—15 kg/cm ) pressure (44). Precursors to quaternary ammonium amphoteric surfactants have been made by reaction of ethylene chlorohydrin with tertiary amines containing a long chain fatty acid group (45). 

Ghlorohydrination with er -All l Hypohalites. Olefins react with ethyl hypochlorite [624-85-1] to form the corresponding chlorohydrin (49). In 1938 both Shell Development Co. (50) and Arthur D. Litde, Inc. (51) patented the preparation of chlorohydrins by the reactions of olefins with tertiary alkyl hypochlorites. Examples with ethylene and propylene in the Shell patent reported chlorohydrin yields of greater than 95% with tert-huty hypochlorite [507-40-4]. 

The chlorohydrin process (24) has been used for the preparation of acetyl-P-alkylcholine chloride (25). The preparation of salts may be carried out mote economically by the neutralization of choline produced by the chlorohydrin synthesis. A modification produces choline carbonate as an intermediate that is converted to the desired salt (26). The most practical production procedure is that in which 300 parts of a 20% solution of trimethyl amine is neutralized with 100 parts of concentrated hydrochloric acid, and the solution is treated for 3 h with 50 parts of ethylene oxide under pressure at 60°C (27). 

Like the formation of a-cyanohydrins, this reaction is catalyzed by bases or cyanide ion, but unlike the a-cyanohydrin case this reaction is not reversible, and under certain conditions it can proceed with violence. Ethylene cyanohydrin can also be prepared by the reaction of ethylene chlorohydrin and alkaH cyanides (39). 

There have been a number of cell designs tested for this reaction. Undivided cells using sodium bromide electrolyte have been tried (see, for example. Ref. 29). These have had electrode shapes for in-ceU propylene absorption into the electrolyte. The chief advantages of the electrochemical route to propylene oxide are elimination of the need for chlorine and lime, as well as avoidance of calcium chloride disposal (see Calcium compounds, calcium CHLORIDE Lime and limestone). An indirect electrochemical approach meeting these same objectives employs the chlorine produced at the anode of a membrane cell for preparing the propylene chlorohydrin external to the electrolysis system. The caustic made at the cathode is used to convert the chlorohydrin to propylene oxide, reforming a NaCl solution which is recycled. Attractive economics are claimed for this combined chlor-alkali electrolysis and propylene oxide manufacture (135). 

Ethylene oxide [75-21-8] was first prepared in 1859 by Wurt2 from 2-chloroethanol (ethylene chlorohydrin) and aqueous potassium hydroxide (1). He later attempted to produce ethylene oxide by direct oxidation but did not succeed (2). Many other researchers were also unsuccesshil (3—6). In 1931, Lefort achieved direct oxidation of ethylene to ethylene oxide using a silver catalyst (7,8). Although early manufacture of ethylene oxide was accompHshed by the chlorohydrin process, the direct oxidation process has been used almost exclusively since 1940. Today about 9.6 x 10 t of ethylene oxide are produced each year worldwide. The primary use for ethylene oxide is in the manufacture of derivatives such as ethylene glycol, surfactants, and ethanolamines. 

Dioxolanes haye been prepared from a carbonyl compound and an epoxide (e.g., ketone/SnC, CCI4, 20°, 4 h, 53% yield or aldehyde/ Et4N Br, 125-220°, 2-4 h, 20-85% yield ). Perhalo ketones can be protected by reaction with ethylene chlorohydrin under basic conditions (K2CO3, pentane, 25°, 2 h, 85% yield or NaOH, EtOH—H2O, 95% yield ). 

Diethylaminoethyl alcohol has been prepared by reduction of diethylaminoacetic ester with sodium and alcohol, by the action of ethylene chlorohydrin on diethylamine, and by the action of ethylene oxide on diethylamine. ... 

Tetramethylene chlorohydrin was first prepared in a pure state by the action of thionyl chloride on tetramethylene glycol in the presence of pyridine. The method given here has been published recently... 

I-Cyano-3-phenylurea, first obtained by the alkaline hydrolysis of 5-anilino-3- -toluyl-l,2,4-oxadiazole, has been prepared by tlic condensation of phenyl isocyanate and the sodium salt of cyanamide. However, in these publications an incorrect structural assignment for the product was made. 1-Cyano-3-phenyl-urea is obtained also, together with other products, by warming gently l-cyano-3-phenylthiourea with caustic soda in the presence of ethylene chlorohydrin, or by gradually adding caustic )otash to a boiling solution of 1-phenyldithiobiuret and ethylene clilorohydrin in ethanol. ... 

About 2 X 10 Ib/yeai of 1,2-epoxypropane is produced in the United States as an intennediate in the preparation of various polymeric materials, including polyurethane plastics and fofflns and polyester resins. A large fraction of the 1,2-epoxypropane is made from propene by way of its chlorohydrin. 

The trimethylene chlorobromide used boiled at 142-1470. It may be prepared in 75-85 per cent yields from trimethylene chlorohydrin (p. 112) by the general method for the preparation of alkyl bromides described in Org. Syn. 1,1. 

J-Chloropropionic acid has been prepared by the hydrolysis of ethylene cyanohydrin with hydrochloric acid,1 and by the oxidation of /S-chloropropionaldehyde2 or of trimethylene chlorohydrin 3 by nitric acid. 

Trimethylenc chlorohydrin has been prepared from tri-methylene glycol by the action of dry hydrogen chloride... 

The general plan of Organic Syntheses has been discussed in the prefaces of the previous volumes. In this volume are published two distinctly different methods of preparation for each of two compounds. The directions for producing /3-chloro-propionic acid first from acrolein and second from trimethylene chlorohydrin, and for producing trimethylacetic acid first from terJ-butyl chloride and second from pinacolone, have been included. This has been deemed advisable since in some countries one raw material is more readily available than the other. 

The optically active glycols are a convenient starting material for the preparation of optically active carbinols, hydroxy-acids, etc. The biological method of asymmetric reduction is perhaps the only convenient method for the preparation of these glycols. The steps in the preparation of other optically active glycols arc identical with those of /-propylene glycol. In some cases it is found convenient to oxidize the chlorohydrin to the... 

Table 7.2 Enzymatic preparation of both enantiomers of chiral chlorohydrins...

A related allenylzinc reagent was prepared by the addition of LDA to a solution of trimethylsilylpropargyl chloride and ZnBr2 in THF at -78°C (Eq. 9.128) [107], Anti propargylic chlorohydrins adducts were obtained when aldehydes were allowed to react with this reagent. Subsequent treatment with DBU gave the alkynyloxiranes (Eq. 9.129). 

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