Olefin oligomers

Olefin-CO coploymers Olefin p-complexes Olefin Fibers Olefin hydroformylation Olefin hydrogenation Olefimc alcohols Olefin isomerization Olefin metathesis Olefin oligomers Olefin oxides... 

Hydrocarbons. Synthesized hydrocarbons are the most popular of the synthetic base stocks. These are pure hydrocarbons (qv) and are manufactured from raw materials derived from cmde oil. Three types are used olefin oligomers, alkylated aromatics, and polybutenes. Other types, such as cycloahphatics, are also used in small volumes in specialized apphcations. 

Olefin oligomers are used widely as automotive lubricants. They often are combiaed with some of the organic esters as base fluids ia engine oils, gear oils, and hydrauHc fluids, eg, for equipment intended for operation ia extremely cold climates, and for premium oils, eg, for the service station market ia temperate climates. 

Dicumjlphenol (2,4-DCP) or 2,4-bis(l-methyl-l-phenylethyl)phenol is produced by the alkylation of phenol with a-methylstyrene under acidic catalysis. The cmde alkylation product contains 4-cumylphenol, 2,4-dicumylphenol, and 2,4,6-tricumylphenol along with some olefin oligomers. Pure... 

Miscellaneous Copolymers. VP has been employed as a termonomer with various acryUc monomer—monomer combinations, especially to afford resins usehil as hair fixatives. Because of major differences in reactivity, VP can be copolymerized with alpha-olefins, but the products are actually PVP grafted with olefin or olefin oligomers (151,152). Likewise styrene can be polymerized in the presence of PVP and the resulting dispersion is unusually stable, suggesting that this added resistance to separation is caused by some grafting of styrene onto PVP (153). The Hterature contains innumerable references to other copolymers but at present (ca 1997), those reviewed in this article are the only ones known to have commercial significance. 

Our studies have confirmed that the oligomerisation of styrene by perchloric acid is both chemically and kinetically simple. However, the reactions which follow completion of the polymerisation, and during which carbonium ions are formed and destroyed, are complicated. They can be rationalised in terms of equilibria involving ions, acid, double bonds, and esters cyclisation of olefinic oligomers and formation of polyenes by way of allylic ions add further complications. We have thus shown in some detail just why such systems must be treated with the greatest circumspection if they are to yield valid information. 

Frequently substantially more than catalytic amounts of a Lewis acid metal halide are required to effect Friedel-Crafts alkylation. This is due partly to complex formation between the metal halide and the reagents or products, especially if they contain oxygen or other donor atoms. Another reason is the formation of red oils. Red oils consist of protonated (alkylated) aromatics (i.e., arenium ions) containing metal halides in the counterions or complexed with olefin oligomers. This considerable drawback, however, can be eliminated when using solid acids such as clays,97 98 zeolites (H-ZSM-5),99,100 acidic cation-exchange resins, and perfluoro-alkanesulfonic acid resins (Nafion-H).101-104... 

Olefin oligomers -as hydraulic fluids [HYDRAULIC FLUIDS] (Vol 13)... 

A further breakthrough was the synthesis of enantiomeric sterorigid ansa-metallocenes by Brintzinger and co-workers [33] and the discovery by Ewen [34] that such racemic metallocene/methylalumoxane systems generate isotactic polypropylene. It was further found that the metallocene structure determines the polymer structure [35-37]. Again, with these compounds polyolefins such as syndiotactic polypropylene become available on a large scale [38]. Indeed, metallocene/methylalumoxane catalysts offer new prospects for olefin oligomers and polymers [39 2],... 

In order to introduce LCBs of different structures, vinyl-terminated olefin oligomers have been used in copolymerization with ethylene (as well as propylene, see Section 4.09.4.2.8). Such macromonomers can be prepared by ethylene oligomerization,531,567 E/P co-oligomerization,568 or propylene oligomerization.569 In the last case, a catalyst with a very high selectivity for /3-Me transfer is necessary, in order to produce oligomers with the required Q-olefinic terminal. 

The formation of coke precursors, including olefin oligomers, must be suppressed to extend catalyst lifetime. 

Developments in PAO technology include using acidic aluminosilicate shape-selective catalysts. Use of chromium on silica gel catalyst and a shape-selective metallosilicate produced olefin oligomers as suitable intermediates for reaction with an enophile to produce polar synthetic base stocks [33],... 

There have been numerous reports (ref. 13-16) that methanol conversion has autocatalytic character and is accelerated by added olefin (or C3+ alcohol). Espinoza s results indicating that olefin oligomers block the zeolite channels cloud the evidence on autocatalysis. They probably explain why added olefins (or alcohols) accelerate conversion over only a narrow temperature range below that at which complete conversion would occur in the absence of added olefin. 

The choice of synthetic hydrocarbons for lubricant use is not restricted to olefin oligomers. It is entirely credible that among the thousands of hydrocarbons of various structures will be found many whose properties make them worthy of attention as possible lubricants. For example, Wilgus, Ettling and Pino [1] investigated the potential usefulness as high-temperature, radiation-resistant hydraulic fluids of a series of diarylalkanes of the general type... 

Olefinic oligomers with a reduced degree of branching were produced with a silica-rich ZSM-22 outer layer catalyst in the oligomerization of a feed containing mixed butenes, diluted with butanes, with the approximate proportions 65% olefins and 35% saturates. It was reported that a high viscosity index lubricant was produced by oligomerization of lower olefins, essentially the C3-C4 fractions, with a medium-pore, shape-selective aluminosilicate HZSM-22 catalyst. ... 

EXCEREX Olefin Oligomer, supplier website (www.mitsuichemicals.com). Mitsui Chemicals America, Inc. 2007 (downloaded 23 October 2007). 

---