Wax cracking

Wax blends Wax cracking Wax crystal modifiers Wax emulsions Waxes... 

Linear a-olefins were produced by wax cracking from about 1962 to about 1985, and were first commercially produced from ethylene in 1965. More recent developments have been the recovery of pentene and hexene from gasoline fractions (1994) and a revival of an older technology, the production of higher carbon-number olefins from fatty alcohols. 

Wax Cracking. One or more wax-cracked a-olefin plants were operated from 1962 to 1985 Chevron had two such plants at Richmond, California, and Shell had three in Europe. The wax-cracked olefins were of limited commercial value because they contained internal olefins, branched olefins, diolefins, aromatics, and paraffins. These were satisfactory for feed to alkyl benzene plants and for certain markets, but unsatisfactory for polyethylene comonomers and several other markets. Typical distributions were C 33% C q, 7% 25% and 35%. Since both odd and... 

Homologous n-a-olefins by pyrolysis of high molecular weight C20-C30 n-alkanes (wax cracking)... 

Table 5 gives typical results of the wax cracking process to surfactant olefins. Compared with the pure a-olefins produced by the oligomerization reactions of ethylene the crack olefins are decreased in quality, especially due to the conjugated diene part (2-4%). Moreover, there are some problems in guaranteeing the wanted amounts of C20-C30 n-alkanes. Therefore in industrially de-... 

Apart from the UOP Pacol process, today s only other meaningful economic process is the Shell higher olefin process (SHOP) in which /z-olefins are produced by ethylene oligomerization. Until 1992 Hiils AG used its own technology to produce -60,000 t/year of /z-olefins by the chlorination of /z-paraffins (from Molex plant) and subsequent dehydrochlorination [13]. In the past, the wax cracking process (Shell, Chevron) played a certain role. In the Pacol and Hiils processes, olefins are obtained as diluted solutions in paraffin (Pacol to max. 20%, Hiils about 30%) without further processing these are then used for alkylation. In contrast, the SHOP process produces pure olefins. 

The ethene-based processes give only even-numbered alkenes (including the one making alcohols) while the other two processes produce both odd and even numbered alkenes. In the last two decades there has been a trend to close down wax cracking alkene plants, and the products are now increasingly derived from ethene. Note that ethene is also a cracker product. 

Recently, a number of a-olefins have been offered commercially. These olefins, made by ethylene polymerization or by wax cracking, are available either as relatively pure compounds or as mixtures of several adjacent members in chain lengths of about six to 20 carbon atoms. These products are largely straight-chain terminal olefins. 

Wax-cracking Quality [wt. % Chevron a-olefin] Ethyl SHOP... 

VI) and 130+ VI (very high VI) base stocks from wax cracking. The success of the plant led to its expansion in 1977 to 6000 bpd. The company s objectives were similar to others as this new technology emerged—namely, to have the ability to make base stocks with Vis exceeding 95, to avoid having to use the restricted suite... 

Higher alkylated phenols are obtained by the interaction of phenol and C16-C18 olefins from wax cracking. The corresponding alkylated salicylic acids (formed by Kolbe-Schmitt carboxylation) are lubricants for diesel engines. 

Historically, the olefins of such type have been obtained by both alcohol dehydration and paraffin wax cracking, but these processes have been progressively abandoned in favor of processes based on ethylene oligomerization. 

GTL plants will also make lightly branched paraffins from wax cracking. The branched paraffins can then be used to produce the lightly branched alcohol technologies resembling the Shell Neodol 67 from coal instead of crude oil. More cost-effective and efficient ways to produce surfactants from alternative feedstocks will likely continue to be pursued in the indnstry to remain... 

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