Petroleum refining industry, alkylation

The activity and decay behaviour of the different porous heteropolycompounds were compared in two reactions requiring strong acid sites the n-butane isomerization and the isobutane/2-butene alkylation. Although these two reactions are important in the petroleum refining industry, n-butane isomerization is often used as a "test reaction" since it is known that this reaction requires very strong acid sites and only a limited number of oxides are active in this reaction, under mild conditions (T = 473 K). 

Propylene is manufactured by steam cracking of hydrocarbons as discussed under ethylene. The best feedstocks are propane, naphtha, or gas oil, depending on price and availability. About 50-75% of the propylene is consumed by the petroleum refining industry for alkylation and polymerization of propylene to oligomers that are added to gasoline. A smaller amount is made by steam cracking to give pure propylene for chemical manufacture. 

As mentioned previously, the use of aluminum chloride alkylation has been very limited in the petroleum refining industry. The aluminum chloride catalyst, being somewhat more difficult to handle and regenerate, could not compete economically with H2S04 and HF catalysts for propylene and butylene alkylation. However, aluminum chloride will catalyze ethylene alkylation whereas H2S04 and HF will not. In the past, ethylene alkylation has not been used much because of the higher olefin feed cost (15). 

Much of the propylene is consumed by the petroleum refining industry for alkylation and polymerization to oligomers that are added to gasoline. A smaller amount is used for chemical manufacture. 

In the petroleum refining industry, alkylation is the union of an olefin with an aromatic or paraffinic hydrocarbon ... 

Likely trends in alkylation capacity are almost impossible to predict. The entry of federal and local governments into the control of more and more aspects of industry, especially the petroleum refining industry, is alarming and renders decision-making on technical and economic bases virtually meaningless. The pell-mell rush to "control" has prompted grave misgivings in every sector of society. It is stated in one... 

When an alkene is used in the alkylation of arenes, metal halides with hydrogen halide or water as cocatalyst, protic acids, and acidic oxides can be used as catalysts. Both linear and cyclic alkenes are used in alkylations. Alkylation with alkenes is usually preferred in industry because the processes are simpler and olefins are readily and cheaply available in pure form from petroleum refining processes. 

Isomerization of straight-chain to branched alkanes also increases the octane number, as do alkylates produced by alkene-isoalkane alkylation (such as that of isobutane and propylene, isobutylene, etc.). These large-scale processes are by now an integral part of the petroleum industry. Refining and processing of transportation fuels became probably the largest-scale industrial operation. 

In refining of petroleum, sulfuric acid is used as a catalyst for alkylation reactions and in the manufacture of other organic derivatives. Chemicals production includes virtually every heavy chemical industry. For example, the production of sodium and aluminum sulfates, hydrochloric and hydrofluoric acids, insecticides, detergents, and many other chemicals all involve the use of H2S04. 

---