Ethylene growth

Oxonatlon of llnoar alpha oloflnt glvot primary alcohols of a high dogroo of llnoarlty. From this procoss it is possible to obtain odd-numbered, as well as even-numbered, carbon atom alcohols. These represent a new type of plasticizer raw material in the United States since such alcohols are not commercially available from natural sources, the conventional oxo process, or the ethylene growth process. Phthalate esters of these alcohols exhibit the improved performance In PVC compounds expected of linear alcohols. 

Plasticizer manufacturers have long recognized the desirable features of straight chain alcohols as plasticizer raw materials, but until recently, they depended entirely on limited production from natural sources for these products. Presently, mixtures of straight chain alcohols of even carbon number are available at commercially attractive prices from the ethylene growth process (2), but the pure alcohols are still too expensive generally to interest the plasticizer manufacture. 

Finally the ESR spectrum of Nb(7r-allyl)4/alumina was unaffected by the addition of ethylene gas to the ESR sample tube. It is assumed that polyethylene is produced in this process since polymer can be isolated from larger scale reactions under similar conditions. The accepted mechanism for the ethylene growth reaction postulates a steady-state concentration of a a-bonded transition metal-hydrocarbon species which would be expected to modify the ESR spectrum of the supported complex. A possible explanation for the failure to detect a change in the ESR spectrum may be that only a small number of the niobium sites are active for polymerization. Although further experiments are needed to verify this proposition, it is consistent with IR data and radiochemical studies of similar catalyst systems (41, 42, 43). 

Figure 4.17 Production of alcohols from ethylene growth products. Note A+B+C=N.

Fig. 5. 20 Worldwide propylene and ethylene growth rates 5.3.2 FCC olefin additives...

These results again demonstrate that two independent mechanisms of olefin generation operate simultaneously. The Schulz-Flory distribution obviously arises from an ethylene growth reaction on some sites that have a strong disposition to terminate the chain growth. The 1-hexene spike probably arises from the formation of chromacycloheptane, as has been observed with other chromium catalysts [674],... 

Butadiene. Butadiene pricing seems to have reflected increased supply from both ethylene by-product sources and old plants partially modified to increase yields. The favored route for new direct capacity is probably butane dehydrogenation but the growth of more U.S. ethylene capacity based on gas oil would substantially increase by-product supply. Since butadiene growth is slower than ethylene growth with a heavy shift toward refinery liquids, cracking for ethylene would tend to depress butadiene supply/demand balances and prices. 

Ethylene-derived alcohols were first produced in the early 1960s by two main processes. The hydroformylation process and the Ziegler chemistry are the most important commercial rontes today. The Ziegler process involves three basic steps (1) addition of ethylene to triethylalnmi-num to build the higher molecular weight trialkylaluminum called the ethylene growth product,... 

Substances producing ethylene Growth Inhibitors and retardators... 

The organic halide-ethylene growth reaction can be catalyzed by Ru(CO)3 (PPh3)2 (Magoon et ai, 1975). 

For decades, linear dialkyl phthalate plasticizers with sidechains between seven and eleven carbons in length, averaging 9 carbons (71 IP and more recently L9P), have been widely used in many North American made flexible PVC products for outdoor applications. Linear dialkyl phthalates are defined as those derived from commercial alcohols with very little side chain branching. These alcohols range from 100% normal products made by ethylene growth in the Ziegler process to 65% normal, 35% 2-methyl branched products made from oxonation of normal alpha olefins.[l] (91 IP and 1 IP have also been available, but at a premium price.) The relatively less branched alkyl sidechains in a linear, as opposed to a branched, dialkyl phthalate afford measurably improved... 

Polymerization of styrene is carried out under free radical conditions often with benzoyl peroxide as the initiator Figure 1111 illustrates a step m the growth of a poly styrene chain by a mechanism analogous to that of the polymerization of ethylene (Sec tion 6 21)... 

The price of acetaldehyde duriag the period 1950 to 1973 ranged from 0.20 to 0.22/kg. Increased prices for hydrocarbon cracking feedstocks beginning in late 1973 resulted in higher costs for ethylene and concurrent higher costs for acetaldehyde. The posted prices for acetaldehyde were 0.26/kg in 1974, 0.78/kg in 1985, and 0.92/kg in 1988. The future of acetaldehyde growth appears to depend on the development of a lower cost production process based on synthesis gas and an increase in demand for processes based on acetaldehyde activation techniques and peracetic acid. 

Eig. 1. Ziegler ethylene chain growth. Theoretical (Poisson) distribution of primary alcohols at ( ) 2.5, (- -... 

This second reaction leads to the small amount of branching (usually less than 5%) observed in the alcohol product. The alpha olefins produced by the first reaction represent a loss unless recovered (8). Additionally, ethylene polymerisation during chain growth creates significant fouling problems which must be addressed in the design and operation of commercial production faciUties (9). 

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. 

Ethylene. Ethylene [74-85-1/, (7) is considered to be one of the principal plant growth regulators in the natural products family. However,... 

United States. The demand for acetylene generally peaked between 1965 and 1970, then declined dramatically until the early 1980s, and has been slowly increasing at between 2 and 4% per year since. The dramatic decline was related to increased availabiHty of low cost ethylene, an alternative feedstock for many chemicals, and the recent increase is due to the modest growth of acetylenic chemicals, particularly 1,4-butanediol. 

Commercial production of PE resias with densities of 0.925 and 0.935 g/cm was started ia 1968 ia the United States by Phillips Petroleum Co. Over time, these resias, particularly LLDPE, became large volume commodity products. Their combiaed worldwide productioa ia 1994 reached 13 X 10 metric t/yr, accouatiag for some 30% market share of all PE resias ia the year 2000, LLDPE productioa is expected to iacrease by 50%. A aew type of LLDPE, compositioaaHy uniform ethylene—a-olefin copolymers produced with metallocene catalysts, was first introduced by Exxon Chemical Company in 1990. The initial production volume was 13,500 t/yr but its growth has been rapid indeed, in 1995 its combiaed production by several companies exceeded 800,000 tons. 

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