ネオペンチル型多価アルコールの塩化水素ガスによる塩素化に関する研究(第2報) : ペンタエリトリットテトラアセテートの塩素化

概要

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Chlorination of pentaerythritol tetraacetate (PETA), pentaerythritol dichlorodiacetate (PEDCDA), and pentaerythritol trichloromonoacetate (PETCMA) with gaseous hydrogen chloride has been investigated in the presence of zinc chloride PETA was chlorinated in a stepwise manner to form PETCMA . Essentially no pentaerythritol tetrachloride, the fully chlorinated product, was detected in the products. The reaction velocity of PETCMA was extremely small and was of the order of 1/170-1/370 that of the other reactions. Under the constant flow of hydrogen chloride gas, the chlorination velocity of PEDCDA was proportional to the first order of the reactant concentration and zinc chloride concentration. It is believed that zinc chloride first coordinates toward the carbonyl group of the reactant. Ligand exchange has then to occur to effect the desired reaction. The difficulty for zinc chloride to coordinate toward the carbonyl group of PETC MA would explain the difficulty in chlorination. Hydrogen chloride probably converts the Zn-OCOCH<SUB>3</SUB> linkage formed by the ligand exchange into a Zn-Cl linkage, thus eliminating the acetic acid from the system to prevent the reverse reaction.
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