Kinetics of heterogeneous condensation of acetophenone with glycerol under nonisothermal conditions
Reactions of ketones with polyhydric alcohols result in formation of cyclic ketals, which are used widely in various branches of the national economy. In particular, these compounds may serve as plasticizers for polymeric materials, the demand for which is growing continuously. Formation of ketals is a catalytic process, and may proceed either in one-phase or a two-phase system, depending on the miscibility of the reactants. The reaction in one-phase systems, catalyzed by acids, salts, and peroxides, has been studied more fully. However, it is not always possible to find the medium and conditions in which alcohols and ketones form a homogeneous system. Such reactions include condensation of acetophenone (AP) with glycerol (GL), catalyzed by p-tolluenesulfonic acid (p-TSA), which we have investigated. The choice of the components was promoted by the need for recovery of wastes and planned utilization of intermediate products of joint manufacture of propylene oxide and styrene. Some of these contain considerable amounts of acetophenone. The formulated physical prerequisites of the kinetic model of heterogeneous condensation of acetophenone and glycerol show that the reaction steps are dissociation of the catalyst and formation of the complex and of the dioxolane. The last step occurs at the interface and is rate-determining. The kinetic model of the reaction was confirmed experimentally. It was shown, in particular, that the reaction rate is proportional to the square root of the catalyst concentration. The method was substantiated and the energy characteristic including the activation energy E of the controlling step and certain heat effects was estimated: ..delta..H = 325 kJ/mole. The estimated value of E corresponds to the activation barrier for bimolecular reactions in liquid media.
- Research Organization:
- Voronezh Technological Inst., USSR
- OSTI ID:
- 5181982
- Journal Information:
- J. Appl. Chem. USSR (Engl. Transl.); (United States), Vol. 55:12; Other Information: Translated from Zh. Prikl. Khim.; 55: No. 12, 2738-2742(Dec 1982)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ACETOPHENONE
CHEMICAL REACTION KINETICS
GLYCEROL
ACTIVATION ENERGY
PLASTICIZERS
WASTE PROCESSING
ALCOHOLS
ENERGY
HYDROXY COMPOUNDS
KETONES
KINETICS
MANAGEMENT
ORGANIC COMPOUNDS
PROCESSING
REACTION KINETICS
WASTE MANAGEMENT
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)