US 20080249324A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2008/0249324 A1 Davis (43) Pub. Date: Oct. 9, 2008 (54) PROCESS FOR PREPARING Publication Classification 1,3-DIBROMOACETONE, 1-3-DCHLOROACETONE AND (51) Int. Cl. EPICHLOROHYDRIN C07D 301/02 (2006.01) CD7C 45/63 (2006.01) (76) Inventor: Clark S. Davis, Oakley, CA (US) (52) U.S. Cl. ......................................... 549/519;568/.407 Correspondence Address: The Dow Chemical Company Intellectual Property Section, P.O. Box 1967 (57) ABSTRACT Midland, MI 48641-1967 (US) A process for preparing 1,3-dibromoacetone, 1-3-dichloro (21) Appl. No.: 10/593,397 acetone and epichlorohydrin which comprises: (a) reacting acetone with 2 moles of bromine to make a mixture of bro (22) PCT Fled: May 17, 2005 minated acetone derivatives and byproduct hydrogen bro mide; (b) equilibrating the mixture of brominated acetone (86) PCT NO.: PCT/US2005/01719.3 derivatives and hydrogen bromide to produce 1,3-dibromoac etone as the major product; (c) crystallizing the 1,3-dibro S371 (c)(1), moacetone; and (d) isolating the 1,3-dibromoacetone. The (2), (4) Date: Oct. 4, 2006 process may further include the steps of (e) reacting the 1,3-dibromoacetone with a chloride source to produce 1,3- Related U.S. Application Data dichloroacetone; (f) hydrogenating the isolated 1,3-dichloro (60) Provisional application No. 60/573,497, filed on May acetone to produce 1,3-dichlorohydrin; and (g) cyclizing the 21, 2004. 1,3-dichlorohydrin with a base to produce epichlorohydrin. US 2008/0249324 A1 Oct. 9, 2008 PROCESS FOR PREPARING 0010 (c) crystallizing the 1,3-dibromoacetone in the mix 1,3-DIBROMOACETONE, ture of brominated acetone derivatives; and 1-3-DCHLOROACETONE AND 0011 (d) isolating the 1,3-dibromoacetone from the mix EPICHLOROHYDRIN ture of brominated acetone derivatives (mother liquor). 0012. In a second aspect, the present invention is a process which comprises. 0001. The present invention relates to a process for mak 0013 (a) equilibrating the mixture of brominated acetone ing 1,3-dibromoacetone and 1,3-dichloroacetone. 1,3-dichlo derivatives mother liquor remaining from the first aspect with roacetone prepared by the process of the present invention is hydrogen bromide to produce 1,3-dibromoacetone as the useful for manufacturing epichlorohydrin. major product; 0002 1,3-Dibromoacetone belongs to the class of 1,3- 0014 (b) crystallizing the 1,3-dibromoacetone in the mix dihaloacetones which includes dichloroacetone and difluoro ture of brominated acetone derivatives mother liquor; and acetone. These dihaloacetone derivatives have been shown to 00.15 (c) isolating the 1,3-dibromoacetone from the mix be useful for making intermediates for pharmaceuticals and ture of brominated acetone derivatives mother liquor. fine chemicals as well as industrial chemicals including 0016. In a third aspect, the present invention is a process epichlorohydrin. However, there is currently a need for the for preparing 1,3-dibromoacetone which comprises: preparation of 1,3-dihaloacetone derivatives in high yield. 0017 (a) reacting acetone with bromine to make a mixture 0003. The preparation of 1,3-dichloroacetone directly of brominated acetone derivatives and hydrogen bromide from the reaction of acetone with chlorine produces excessive byproduct; amounts of 1,1-dichloroacetone as well as trichloroacetone 0018 (b) equilibrating the mixture of brominated acetone derivatives. It has been proposed that 1,3-dichloroacetone can derivatives to produce 1,3-dibromoacetone as the major prod be made selectively by reaction of acetone with chlorine. For uct; and example, Kurkov (U.S. Pat. No. 4,251,467 (Feb. 17, 1981)) 0019 (c) conducting a reactive crystallization of the 1,3- discloses making 1,3-dichloroacetone by the reaction of dibromoacetone while concurrently equilibrating the mixture acetone and chlorine in the presence of an iodine containing of brominated acetone derivatives. compound. The costs associated with this process are high 0020. In a fourth aspect, the present invention is a process due to the high cost of iodine and the production of large which comprises isolating crystalline 1,3-dibromoacetone amounts of unwanted chlorinated byproducts and hydrogen from the third aspect step (c). chloride. 0021. In a fifth aspect, the present invention is a process 0004) 1,3-Dibromoacetone is difficult to prepare in high which comprises: yield since direct bromination of acetone or bromination of 0022 (a) converting to bromine the hydrogen bromide bromoacetone leads to multiple products. An equilibration byproduct produced in the reaction of acetone and bromine; reaction catalyzed by hydrogen bromide interconverts the and products from dibromination of acetone to give a mixture 0023 (b) recycling the recovered bromine for use in the containing monobromoacetone, 1,1-dibromoacetone, 1,3-di acetone bromination reaction. bromoacetone and tribromoacetone with varying amounts of higher brominated products and acetone. The equilibrium 0024. In a sixth aspect, the present invention is a process reaction limits the maximum concentration of 1,3-dibro for preparing 1,3-dichloroacetone which comprises: moacetone to 70 percent of the total mixture. 0025 (a) reacting 1,3-dibromoacetone with a chloride 0005 V. P. Kutrov and A. N. Koskyuk (SU 1,567.568) Source to produce a mixture of major product 1,3-dichloro describe the preparation of 1,3-dibromoacetone by reacting acetone and byproduct bromide; and acetone with two molar equivalents of bromine to give a 0026 (b) isolating the 1,3-dichloroacetone. mixture of brominated acetone products. This mixture of 0027. In a seventh aspect, the present invention is a process brominated acetone products is treated with sodium bisulfite, for preparing epichlorohydrin which comprises: the sodium bisulfite adduct of 1,3-dibromoacetone is isolated 0028 (a) reacting 1,3-dibromoacetone with a chloride by filtration and then the sodium bisulfite adduct of 1,3- Source to produce a mixture of major product 1,3-dichloro dibromoacetone is decomposed with sulfuric acid. 1,3-Dibro acetone and byproduct bromide; moacetone is isolated from the sulfuric acid solution by fil 0029 (b) reducing the 1,3-dichloroacetone to produce 1,3- tration and then purified by recrystallization. This process is dichlorohydrin; and complex requiring multiple chemical steps, gives 1,3-dibro 0030 (c) cyclizing the 1,3-dichlorohydrin with a base to moacetone in low yield and produces a large amount of bro produce epichlorohydrin. minated acetones derivatives and hydrogen bromide as waste 0031. In an eighth aspect, the present invention is a process products. which comprises: 0006. It would be desirable to provide a commercially 0032 (a) reacting 1,3-dibromoacetone with a chloride feasible and effective process for the preparation of 1,3-di Source to produce a mixture of major product 1,3-dichloro bromoacetone and 1,3-dichloroacetone. acetone and byproduct bromide; 0007. In a first aspect, the present invention is a process for 0033 (b) converting the byproduct bromide produced in preparing 1,3-dibromoacetone which comprises: step (a) to bromine; 0008 (a) reacting acetone with bromine to make a mixture 0034 (c) recycling the bromine to the acetone-bromina of brominated acetone derivatives and hydrogen bromide tion reaction; and byproduct; 0035 (d) optionally, recycling any chloride source formed 0009 (b) equilibrating the mixture of brominated acetone in step (b) to step (a). derivatives to produce 1,3-dibromoacetone as the major prod 0036. In a ninth aspect, the present invention is a process uct; which comprises preventing or minimizing the formation of US 2008/0249324 A1 Oct. 9, 2008 large amounts of tetrabromoacetone by thoroughly mixing 0047. The yield of the acetone bromination process may the bromine and the acetone before the addition of a catalyst be increased by equilibration of the remaining brominated or the reaction self-initiates. acetone derivatives mother liquors in the presence of hydro 0037. In a tenth aspect, the present invention is a process gen bromide. The mother liquors remaining after removal of which comprises using a mixture of brominated acetone crystalline 1,3-dibromoacetone including bromoacetone, derivatives as the solvent for the reaction of acetone and 1,1-dibromoacetone and tribromoacetone can be equilibrated bromine. to give 1,3-dibromoacetone as the major product. The com 0038. Other aspects of the present invention will become bination of crystallization and isolation of 1,3-dibromoac apparent from the following detailed description and claims. etone followed by equilibration of the remaining mother 0039. The bromoacetone derivatives formed by reacting liquors can be repeated until essentially complete conversion acetone with bromine, that is in the acetone bromination step to 1,3-dibromoacetone is achieved. This equilibration step of the present invention are represented by Formula I as may be conducted as a separate step or the mother liquors may follows: be recycled to the acetone bromination reaction step where it could serve as all or part of the reaction solvent. The mother liquors may also be directly added to an equilibration step Formula I following the reaction of acetone with bromine. 0048 Surprisingly, it has also been found that cooling a X X solution of the dibromoacetone mixture in the presence of hydrogen bromide results in reactive crystallization of 1,3- Y Yi dibromoacetone. Simultaneous crystallization of 1,3-dibro Z Z. moacetone and equilibration of the remaining mixture of bromoacetone, 1,1-dibromoacetone and tribromoacetone 0040 wherein X is bromine, Zand Z are hydrogen, Y.Y. results in conversion of the mixture to 1,3-dibromoacetone in and X’ are individually hydrogen or bromine. high yield. The concentration of 1,3-dibromoacetone in the 0041. It has been found that during the reaction of acetone overall contents including both crystallized 1,3-dibromoac with two moles of bromine that the formation of higher bro etone and the equilibrium solution can be increased to greater minated acetone derivatives such as tetrabromoacetone can than 95 percent by reactive crystallization.