1- Chloro-2-propanol chlorohydrin

SYNS 3-CHLORPROPAN-l-OL I-PROPANOL, 3-CHLORO- TRIMETHYLENE CHLOROHYDRIN... 

Synonyms 1-Chloro-2-hydroxypropane 1-Chloroisopropyl alcohol 2-Propanol, 1-chloro- Propylene chlorohydrin a-Propylene chlorohydrin... 

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. 

The l-chloro-2-propanol isomer represents about 85% of the chlorohydrin produced. In order to minimise the formation of dichlotide coproduct and ether, the reactant compositions are chosen such that the effluent Hquid contains 4—5 wt % propylene chlorohydrin. Under these conditions, the yield of chlorohydrin, dichloride, and ether from the reactants is reported to be 87—90, 6—9, and 2%, respectively (109,110,112). 

Table 2 gives physical property data for propylene chlorohydrins. 2-Chloro-l-propanol [78-89-7] HOCH2CHCICH2, is also named 2-propylene chlorohydrin, 2-chloropropyl alcohol, or 2-chloro-l-hydroxypropane. l-Chloro-2-propanol [127-00-4] CICH2CHOHCH2, also known as j -propjlene chlorohydrin, 1-chloroisopropyl alcohol, and l-chloro-2-hydroxypropane, is a colorless Hquid, miscible in water, ethanol, and ethyl ether. 

Hydrolysis to Glycols. Ethylene chlorohydrin and propylene chlorohydrin may be hydrolyzed ia the presence of such bases as alkaU metal bicarbonates sodium hydroxide, and sodium carbonate (31—33). In water at 97°C, l-chloro-2-propanol forms acid, acetone, and propylene glycol [57-55-6] simultaneously the kinetics of production are first order ia each case, and the specific rate constants are nearly equal. The relative rates of solvolysis of... 

Formation of Cyclic Carbonates. In the absence of water, chlorohydrins such as 2-chloroethanol and l-chloro-2-propanol react with an alkah carbonate or bicarbonate to produce cycHc carbonates such as ethylene carbonate [96-49-1] and propylene carbonate [108-32-7] ia yields of up to 80%... 

The merchant market for chi orohydrin s is small, primarily for specialty appHcations. Ethylene chlorohydrin is sold ia the United States by BASF Corp., Parsippany, N.J., available ia 230 kg net lined steel dmms. Glycerol monochlorohydrin (3-chloro-l,2-propanediol) is available from Dixie Chemical Co., Houston, Tex., in lined steel dmms (227.3 kg net) from Raschig Corp., Richmond, Va. and from Henley Chemicals, Inc., Montvale, N.J., ia steel dmms (240 kg net). Glycerol dichi orohydrin (l,3-dichloro-2-propanol) is not currentiy being produced for the U.S. merchant market but has been available ia the past at a selling price of 5—6/kg. 

In an older version of the synthesis, propylene and chlorine react in an aqueous solution to form propylene chlorohydrin.192-194 The slightly exothermic reaction maintains the 30-40°C reaction temperature to yield isomeric propylene chlorohy-drins (l-chloro-2-propanol/2-chloro-1-propanol = 9 1). The main byproduct is 1,2-dichloropropane formed in amounts up to 10%. The product propylene chlorohydrin then undergoes saponification to propylene oxide with calcium hydroxide or sodium hydroxide. 

More recently Bradley and co-workers288 demonstrated a fourth significant product in this reaction to be l,3-dichloro-2-propanol. formed by addition of hydrochloric acid to epiehlorohydrin. These authors then showed that under suitable conditions phenyl glycidyl ether can be mode to react wjth a chlorohydrin. There are formed in this manner a new epoxide and l-chloro-D-phenoxy-2-propanol, ah... 

Propylene Chlorohydrins Use l-Chloro-2-propanol Practical Grade, containing 25% 2-Chloro-l-propanol, available from Aldrich Chemical Company, Milwaukee, WI 53233. 

Calculation Prepare a standard curve for the summed signal areas for each of the controls against the calculated propylene chlorohydrin concentrations, in mg/kg, derived from the actual weight of chlorohydrin isomers used. Using the summed signal areas corresponding to the l-chloro-2-propanol and 2-chloro-1 -propanol from the sample, determine the concentration of mixed propylene chlorohydrins, in mg/kg, in the sample by reference to the calibration plot. 

Propylene chloride. See Propylene dichloride Propylene chlorohydrin. See 1-Chloro-2-propanol 2-Chloro-1-propanol a-Propylene chlorohydrin s-Propylene chlorohydrin. See 1-Chloro-2-propanol Propylenediamine... 

One method for the preparation of epoxides from alkenes involves (1) treating the alkene with chlorine or bromine in water to form a chlorohydrin (or bromohydrin) followed by (2) treating the halohydrin with a base to bring about intramolecular displacement of Cl . These steps convert propene first to l-chloro-2-propanol and then to methyloxirane (propylene oxide). 

In the chlorohydrination step, the reactants propylene and hypochlorous acid (chlorine and water) are converted into two propylene chlorohydrin isomers (90% l-chloro-2-propanol and 10% 2-chloro-l-propanol). Yields of up to 94% can be achieved in modern commercial plants. The main by-products formed in this reaction step are dichloropropane (3-10%), dichloropropanol (0.3-1.2%), and dichlorodiisopropyl ether (0.2-1.7%). In the second step (dehydrochlorination, also called epoxidation or saponification ) the aqueous propylene chlorohydrin solution is treated with slaked lime or caustic soda. Propylene oxide and calcium or sodium chloride are formed. In a commercial process 1.4-1.5 units of chlorine are consumed to produce one unit of propylene oxide. Typical by-products are monopropylene glycol, epichlorohydrin, glycerol monochlorohydrin, glycerol, propanal, and acetone. In dehydrochlorination, propylene oxide yields of up to 96% can be obtained. 

The chlorohydrin process is carried out in two steps the synthesis of propylene chlorohydrin, PCH, and subsequent dehydrochlorination of PCH to PO. In the first step, propene and chlorine are reacted in aqueous solution to give a mixture of 90 % l-chloro-2-propanol and 10 % 2-chloro-l-propanol... 

---