Cleavage of benzylaryl ethers in the presence of zinc halides
Ether groups constitute one of the primary linkages between aromatic centers present in coal. During the liquefaction of coal under the influence of zinc halides, it is believed that these linkages are cleaved. The details of this process have been studied in the present investigation using benzylphenyl ether (BPE), benzyl-p-tolyl ether (BTE), and benzyl-l-naphthyl ether (BNE) to represent the ether structures present in coal. ZnCl/sub 2/ and ZnBr/sub 2/ were used as catalysts. ZnCl/sub 2/ was found to be catalytically inactive. However, in the presence of HCl it forms a stable adduct which is highly active. HBr/ZnBr/sub 2/ behaves in a manner analogous to HCl/ZnCl/sub 2/ but is tenfold more active. All three ethers react in a similar fashion. In each case cleavage occurs at the oxygen-methylene bond and is accompanied by a small degree of ether rearrangement to form the corresponding hydroxydiarylmethane. The reaction kinetics for BPE, BTE, and BNE can be described in terms of a carbocation mechanism. Rate coefficients for each of the elementary steps have been determined by simulation of the experimentally observed product concentration versus time profiles.
- Research Organization:
- Lawrence Berkeley Lab., CA
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6727499
- Journal Information:
- J. Catal.; (United States), Vol. 87:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
02 PETROLEUM
DECOMPOSITION
REACTION KINETICS
ETHERS
ZINC BROMIDES
CATALYTIC EFFECTS
ZINC CHLORIDES
BROMIDES
BROMINE COMPOUNDS
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
KINETICS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ZINC COMPOUNDS
ZINC HALIDES
010405* - Coal
Lignite
& Peat- Hydrogenation & Liquefaction
020500 - Petroleum- Products & By-Products