Propylene side-chain alkylation with

According to another study, Cs entrapped in nanoporous carbon is an active catalyst in the side-chain alkylation with propylene either in the liquid or in the gas phase to form isbutylbenzene as the main product.444... 

Solid super bases, prepared by successive treatment of y-alumina with alkali metal hydroxide and alkali metal, are highly active catalysts for reactions involving reactive carbanions, and have been commercialised by Sumitomo (Suzukamo et al, 1997). For example, t.vobutylbenzene, the. starting material for ibuprofen (see earlier) is produced by side-chain alkylation of toluene with propylene over a K/KOH/AI2O3 catalyst (Eqn. (14)). 

A number of papers have appeared on the use of layered double hydroxides (e.g. Mg and Al containing oxides). A meixnerite-like catalyst has been reported to give 100% selectivity for diacetone alcohol from acetone at 0 C at close to thermodynamic equilibrium conversion of 23% (Tichit and Fajula, 1999). The side-chain alkylation of toluene with propylene to give isobutyl benzene (for ibuprofen) is a well-known example where Na/K alloy on Na2C03/K2C03 is used as the catalyst. 

Base catalyzed reaction has been covered with reference to transesterification to make biodiesel. A classical case of considerable practical importance is the side chain alkylation of toluene with propylene to give isobutyl benzene, apart from conversion of acetone to diacetone alcohol and isophorone and even here heterogenerous versions are in vogue or under consideration. Microwave assisted reactions are duly covered and it would have been useful to cover ultrasonically assisted reactions, particularly when solid reactant/ catalyst is involved. 

There is now increasing commercial interest in the dimerization of olefins over supported alkali metals, via a carbanion mechanism. Propylene selectively produces 4-methylpent-l-ene and alkylaromatics are alkylated on the side-chain (a-carbon) with these materials. ... 

The primary reactions in the alkylation of isobutane produce octanes from butylenes, heptanes from propylene, and nonanes from amylenes. Also, when dimer and trimer polymers of isobutylene are used with isobutane, the polymer is broken down during the reaction, and the resulting products are branched chain octanes similar to those produced when isobutylene is charged. Sulfuric acid consumption is somewhat higher for the diisobutylenes, however, and there are more side reactions than for isobutylene. 

In the case of 21 the presence of an alkyl chain on the other side of the enamine group16 induces a H rearrangement in low-energy ions with loss of propylene, again followed by the loss of ketene (Scheme 15). 

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