Olefin linear, from ethylene

A.luminum Jilkyl Chain Growth. Ethyl, Chevron, and Mitsubishi Chemical manufacture higher, linear alpha olefins from ethylene via chain growth on triethyl aluminum (15). The linear products are then used as oxo feedstock for both plasticizer and detergent range alcohols and because the feedstocks are linear, the linearity of the alcohol product, which has an entirely odd number of carbons, is a function of the oxo process employed. Alcohols are manufactured from this type of olefin by Sterling, Exxon, ICI, BASE, Oxochemie, and Mitsubishi Chemical. 

The chemical iadustry manufactures a large variety of semicrystalline ethylene copolymers containing small amounts of a-olefins. These copolymers are produced ia catalytic polymerisation reactions and have densities lower than those of ethylene homopolymers known as high density polyethylene (HDPE). Ethylene copolymers produced ia catalytic polymerisation reactions are usually described as linear ethylene polymers, to distiaguish them from ethylene polymers containing long branches which are produced ia radical polymerisation reactions at high pressures (see Olefin POLYMERS, LOWDENSITY polyethylene). 

Most linear a-olefins are produced from ethylene. Ethylene-based capacity in 1993 was 2,196,000 t, compared to only 30,000 t for fatty alcohol-based manufacture. 

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. 

Other half-sandwich Cr complexes which show good activities for olefin polymerization include those with ether and thioether pendant arms (93) and (94) which show activities of 1,435gmmol-1 h-1 bar-1 and 2,010 gmmol-1 h 1 bar-1 respectively.252 The half-sandwich phosphine complex (95) affords a-olefins arising from chain transfer to aluminum,256,257 while the related boratabenzene chromium(III) complex (96) generates linear PF.258,259 Cationic species have also been investigated, and (97) polymerizes ethylene with an activity of 56 gmmol-1 h-1 bar-1.260-263... 

While we know of no experimental thermochemical data for 123, Roth informs us that the enthalpy of formation of 124 is 259 kJmol-1. There are no experimental thermochemical data for 125 either, but it is easy to estimate the desired enthalpy of formation. We may either use the standard olefin approach with ethylene, 1,3-butadiene and (E)-l,3,5-hexatriene (i.e. with CH2=CH2, 33 and 79) or linearly extrapolate these three unsaturated hydrocarbons. From either of these approaches, we find a value of ca 225 kJ mol-1. Cross-conjugation costs some 35 kJ mol-1 in the current case. Interestingly, the directly measured cross-conjugated 1,1-diphenylethylene (126) is only ca 10 kJmol-1 less stable than its directly measured conjugated (E)- 1,2-isomer (40) despite the expected strain effects that would additionally destabilize the former species. 

Linear-1 A process for making linear C6- C10 alpha-olefins from ethylene. Developed by UOP in 1996 but not commercialized as of 1997. 

Alternatively, linear a-olefins can be made from ethylene using Ziegler catalysts to give the ethylene oligomer with a double-bonded end group. 

An olefin may be hydroformvlated to a mixture of aldehydes. The aldehydes are readily converted to alcohols by hydrogenation. Many olefins from ethylene to dodecenes are used in the 0X0 reaction, 0X0 alcohols are typically a mixture of linear and methyl branched primary alcohols. See also Oxo Process. 

Most linear a-olefins are produced from ethylene. 

The resulting alcohols are one type of many alcohols used for detergents. The linear alcohols can be produced from n-paraffins by way of alpha olefins or by way of the chloroparaffins. Or they can be made from alpha olefins formed from Ziegler oligomerization of ethylene. 

Synthetic fatty alcohols fall into three broad categories and are manufactured from two basic raw materials—ethylene and n-paraffins. One group is secondary alcohols which are prepared by oxidation of n-paraffins in the presence of boric acid. A second group consists of oxo alcohols manufactured by hydroformylation of linear olefins which are derived from either n-paraffins or ethylene. Both of these alcohol types are discussed in separate chapters. The last group is Ziegler alcohols which are prepared from ethylene and are the primary subject of this chapter. 

Petrochemical-derived alcohols use a wider range of chemistry but, in each case, an olefin is the starting point. The olefins maybe derived from n-paraffins which give internal olefins, or more linear a-olefins from ethylene oligomerisation. The olefins are converted to alcohols using the oxo process (see Figure 4.16). 

Linear internal monoolefins can be oxidized to linear secondary alcohols. The alpha (terminal) olefins from ethylene oligomerization, described earlier in this chapter, can be converted by oxo chemistry to alcohols having one more carbon atom. The higher alcohols from each of these sources are used for preparation of biodegradable, synthetic detergents. The alcohols provide the hydrophobic hydrocarbon group and are linked to a polar, hydrophilic group by ethoxylation, sulfation, phosphorylation, and so forth. 

Alpha-Sablin [Alpha Sabic Linde] A process for making linear C4 to C10 -olefins from ethylene. A proprietary homogeneous catalyst is used in a bubble-column reactor. Developed between 1994 and 2001 by Sabic and Linde. One plant was under construction in Al-Jubail, Saudi Arabia, in 2005. 

Linear low-density polyethylene with different branching contents was prepared from ethylene, using a combination of catalyst precursors [NiCl(TpMs)] and [ZrCl2Cp2] activated with MAO/TMA (1 1) in toluene at 0°C,24 and also, without the addition of an a-olefin co-monomer, using a combination of the catalyst precursors [NiCl(TpMs)] and ZrCl2Cp2/SMAO-4, by varying the nickel loading mole fraction.25... 

Ethylene for polymerization to the most widely used polymer can be made by the dehydration of ethanol from fermentation (12.1).6 The ethanol used need not be anhydrous. Dehydration of 20% aqueous ethanol over HZSM-5 zeolite gave 76-83% ethylene, 2% ethane, 6.6% propylene, 2% propane, 4% butenes, and 3% /3-butane.7 Presumably, the paraffins could be dehydrogenated catalyti-cally after separation from the olefins.8 Ethylene can be dimerized to 1-butene with a nickel catalyst.9 It can be trimerized to 1-hexene with a chromium catalyst with 95% selectivity at 70% conversion.10 Ethylene is often copolymerized with 1-hexene to produce linear low-density polyethylene. Brookhart and co-workers have developed iron, cobalt, nickel, and palladium dimine catalysts that produce similar branched polyethylene from ethylene alone.11 Mixed higher olefins can be made by reaction of ethylene with triethylaluminum or by the Shell higher olefins process, which employs a nickel phosphine catalyst. 

Keim and co-workers have found that the treatment of Ni(COD)2 with both triphenylphosphine and the phosphorane, Ph3PCHC(0)Ph, affords a nickel(II) chelate complex formally derived from the enolate of Ph2PCH2C(0)Ph (Figure 7.10). ° This crystalline compound, which can be conveniently prepared on a large scale, has been characterized by single crystal X-ray diffraction. Much like o-diphenylphosphinobenzoate, the novel enolate ligand functions as an anionic P-O donor. What is particularly intriguing is that its nickel complex also efficiently catalyzes the formation of linear a-olefins from ethylene. 

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