Chlorohydrin production

In the second proposed alternative process, tert-huty hypochlorite, formed from the reaction of chlorine and tert-huty alcohol, reacts with propylene and water to produce the chlorohydrin. The alcohol is a coproduct and is recycled to generate the hypochlorite (114—116). No commercialisation of the hypochlorous acid and tert-huty hypochlorite processes for chlorohydrin production is known. 

Benson LO, Teta MJ Mortality due to pancreatic and lymphopoietic cancers in chlorohydrin production workers. Br J Ind Med 50 710-716, 1993... 

Olsen GW, Lacy SE, Bodner KM, et al Mortality from pancreatic and lymphopoietic cancer among workers in ethylene and propylene chlorohydrin production. Occup Environ Med 54(8) 592-8, 1997... 

Benson and Teta (1993) studied the mortality among 278 chlorohydrin production workers who had ever been employed at a facility in the United States between 1940 and 1967. The follow-up period was from 1940 to 1988. This was a 10-year update of an earlier study conducted by Greenberg et al. (1990). There were 147 deaths (SMR, 1.0) and 40 cancer deaths (SMR, 1.3) observed. Excesses of pancreatic cancer (SMR, 4.9 95% CI, 1.6-11.4 8 cases) and lymphatic and haematopoietic cancers (SMR, 2.9 95% CI, 1.3-5.8 ... 

Olsen et al. (1997) studied mortality among 1361 men employed at two chlorohydrin production facilities in the United States similar to that studied by Benzon and Teta (1993). There were 300 deaths (SMR, 0.9) and 75 cancer deaths (SMR, 0.9) observed. The risks of pancreatic cancer (SMR, 0.3 95% CI, 0.01-1.4 1 case) and lymphatic and haematopoietic cancers (SMR, 1.3 95% CI, 0.6-2.4 10 cases) were less than those observed by Benson and Teta and no other cancers were observ ed in excess. It was not possible to link mortality to any particular chemical exposure and levels of exposure were not reported. 

Olsen, G.W., Lacy. S.E.. Bodner, K.M., Chau, M., Arceneaux, T.G, Cartmill. J.B.. Ramlow, J.M. Boswell, J.M. (1997) Mortality from pancreatic and lymphopoietic cancer among workers in ethylene and propylene chlorohydrin production. Occup. environ. Med.. 54, 592-598... 

Two studies have examined the risk of cancer among chlorohydrin production workers potentially exposed to bis(2-chloroethyl)ether as well as 1,2-dichloroethane and ethylene chlorohydrin (see the monograph on 1,2-dichloroethane in this volume for a detailed description of the study methods). In one study there was an excess of pancreatic, lymphatic and haematopoietic cancers (Benson Tcta, 1993), while in the other there was not (Olsen et al., 1997). In neither study was it possible to link mortality to any particular chemical exposure. 

Chlorine water adds to alkenes to give chlorohydrin products. 

Alkenes readily react with chlorine to give chloronium ions, which prefer to exist in the open form, that is, with a carbocation intermediate initial addition of chlorine may occur at the top or bottom face, which gives enantiomeric intermediate carbocations. Either of these intermediates may be intercepted by water to give a chlorohydrin product, with an ont/ -outcome in which water attacks at the opposite side to chlorine, and as a racemic pair. Deprotonation of the oxonium intermediate generates the chlorohydrin product. 

Difficulties have been fonnd in the intermolecular coupling reactions of allylsilanes with epoxides other than the simplest ethylene oxide . For example, reactions of allylsilane 99 with epichlorohydrins in the presence of TiCLj or EtAlCl2 give chlorohydrins in moderate to good yields. However, treatment of epichlorohydrin with 99 fnrnishes the expected allylated chlorohydrin product 100 (equation 78). In the intramolecnlar addition of the allylsilane moiety to 2,3-epoxyether moiety of 101, the ratio of 6- and 7-membered ring products is affected by the nature of the Lewis acid. When BF3 OEta is nsed, a mixture of 102 and 103 is obtained (equation 79). Interestingly, 102 is the exclusive product in the TiCU-catalyzed reaction . 

Coates and coworkers recently reported that boron-based Lewis acids such as BCI3 (Equation 18) and BBrs (Equation 19) react with various acyclic and monocyclic 5,c-unsaturated ketones (25) to give the halide-terminated syn-selective halo-Prins cyclization products, thus providing the sterically congested chlorohydrin (26) and bromohydrins (28) [24]. Here, the use of SnCU as a Lewis acid afforded the opposite selectivity to give the trans-chlorohydrin product (27) (Equation 18), highlighting the complementarity often possible with boron halides. 

In light of the availability of 1,2,3-trichloropropane, a large-scale waste of epi-chlorohydrin production, the simple and efficient method for pyrroles allenylation under mild conditions holds promise for further applications in the synthesis of various heterocyclic compounds with a labile hydrogen atom. 

Zinc carboxylates have considerably increased catalytic ability as compared with cadmium. This extends in a positive sense to promotion of the costabilizing effects of phosphites and epoxidized oils, and to need for lower levels (also from its lower atomic weight). Thus, the overall amount of Zn in a liquid stabilizer is likely to be in the range of 1-2 percent, whereas Ba/Cd and Ba/Cd/Zn liquids used Cd levels often reaching 5-10 percent. The associated disadvantages of Zinc versus cadmium are an increased tendency to fail catastrophically instead of gradually, referred to as zinc bum. In addition, zinc salts catalyze hydrolysis of phosphites and promote condensation of the chlorohydrin products of the reaction of ESO with HCl, as well as the development of chromophores from the oxidation of antioxidants. As a result, Ba/Zn and Ca/Zn liquids must be protected from moist air. Some users employ inert gas blankets over liquid stabilizer tanks. 

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