Lower olefins

The general reactivity of higher a-olefins is similar to that observed for the lower olefins. However, heavier a-olefins have low solubihty in polar solvents such as water consequentiy, in reaction systems requiting the addition of polar reagents, apparent reactivity and degree of conversion maybe adversely affected. Reactions of a-olefins typically involve the carbon—carbon double bond and can be grouped into two classes (/) electrophilic or free-radical additions and (2) substitution reactions. 

Products from catalytic cracking units are also more stable due to a lower olefin content in the liquid products. This reflects a higher hydrogen transfer activity, which leads to more saturated hydrocarbons than in thermally cracked products from delayed coking units, for example. 

It seems that silver is a unique epoxidation catalyst for ethylene. All other catalysts are relatively ineffective, and the reaction to ethylene is limited among lower olefins. Propylene and butylenes do not form epoxides through this route. ... 

We looked at a number of water soluble cosolvents (Table 28.3). In all cases aldehyde products were observed. 1,4-dioxane compares well with ethanol as a co-solvent. The data so far shows that 1,4-dioxane shows slightly lower olefin conversion after two hours than ethanol, but shghtly better selectivity. 

Along with catalyst activity, product selectivity is a key issue in cobalt-based FTS.1 For GTL processes the preferred product is long-chain waxy hydrocarbons. It is well known that FT reaction conditions have an important effect on product selectivities. High temperatures and H2/CO ratios are associated with higher methane selectivity, lower probability of hydrocarbon chain growth, and lower olefinicity in the products.105... 

Innovene A proprietary process for polymerizing lower olefins in the gas-phase, incorporating condensed phase technology. Various types of catalysts may be used, but the Insite family of catalysts is now preferred. Developed by BP in the 1990s and first used commercially in 1998. 

Midforming [Middle-range distillate forming] A process for converting lower olefins to transport fuels. The catalyst is either a ZSM-5-type zeolite in which some of the aluminum has been replaced by iron, or a hetero-poly acid. Developed in the 1980s by the National Chemical Laboratory, Pune, India. To be piloted by Bharat Petrochemical Corporation, Bombay, and Davy Poweigas. 

Clerid, M.G. and Ingallina, P. (1993) Epoxidation of lower olefins with hydrogen peroxide and titanium silicate. J. Catal., 140, 71-83. 

The usual procedures of fractional, azeotropic, or extractive distillation under inert gases, crystallization, sublimation, and column chromatography, must be carried out very carefully. For liquid, water-insoluble monomers (e.g., styrene, Example 3-1), it is recommended that phenols or amines which may be present as stabilizers, should first be removed by shaking with dilute alkali or acid, respectively the relatively high volatility of many of these kinds of stabilizers often makes it difficult to achieve their complete removal by distillation. Gaseous monomers (e.g., lower olefins, butadiene, ethylene oxide) can be purified and stored over molecular sieves in order to remove, for example, water or CO2. 

Keyser et al. studied Mn-Co F-T catalysts and found that, under industrial relevant conditions, the WGS activity of the catalysts increases with increasing Mn content, but decreases with increasing pressure. A lower olefin yield was also observed at high pressures. It was stated that structural changes in the cobalt spinel occur over a long period of time and are responsible for the increased hydrogenation activity and increased WGS activity. Mn seems in this... 

Hydroformylation of Other Lower Olefins and Dienes - Lower olefins such as 1-butene or 1,3-butadiene are hydroformylated with acceptable rates using Rh/tppts catalysts according to the RCH/RP process. Hoechst AG Werk Ruhrchemie has developed an attractive new process350 for the hydroformylation of raffinate II, a mixture of 1-butene, cis- and /rbutane derived from the C4 stream of naphtha crackers (after removal of 1,3-butadiene... 

As far back as 1938, it had been proved commercially that repassing or treating the primary aviation gasoline over the cracking catalyst resulted in a product of lower olefin content, higher aromatic content, and improved response to tetraethyllead, decreasing sharply the proportion of alkylate necessary in the blend. 

The synthetic catalyst also yields an aviation fuel of considerably lower olefin content which, in effect, reduces gum-forming tendencies and improves storage stability. 

Because of regulations concerning transportation fuel quality (lowering olefin and aromatics content, lowering volatility), alkylation (in addition to isomerization and oxygenate production) is the most important process in the manufacture of reformulated gasoline.288... 

Catalytic oxidation and ammoxidation of lower olefins to produce a,/3-unsaturated aldehyde or nitrile are widely industrialized as the fundamental unit process of petrochemistry. Propylene is oxidized to acrolein, most of which is further oxidized to acrylic acid. Recently, the reaction was extended to isobutylene to form methacrylic acid via methacrolein. Ammoxidation of propylene to produce acrylonitrile has also grown into a worldwide industry. 

During the history of a half century from the first discovery of the reaction (/) and 35 years after the industrialization (2-4), these catalytic reactions, so-called allylic oxidations of lower olefins (Table I), have been improved year by year. Drastic changes have been introduced to the catalyst composition and preparation as well as to the reaction process. As a result, the total yield of acrylic acid from propylene reaches more than 90% under industrial conditions and the single pass yield of acrylonitrile also exceeds 80% in the commercial plants. The practical catalysts employed in the commercial plants consist of complicated multicomponent metal oxide systems including bismuth molybdate or iron antimonate as the main component. These modern catalyst systems show much higher activity and selectivity... 

Some progress has been made in explaining the splendid catalytic performance of multicomponent bismuth molybdates that are used widely for the industrial oxidations and ammoxidations of lower olefin. We have seen that the catalytic activity and selectivity are greatly enhanced by the multifunctionalization of the catalyst systems. Many functions newly introduced are... 

The oxidative dimerization has recently attracted attention, both from a fundamental viewpoint and as a means for synthesizing aromatics from lower olefins. The reaction is essentially a combination of allyl radicals, by which the oxidation is limited to the abstraction of one hydrogen atom. Typically, the catalysts applied here do not contain Mo03 or a similar component that promotes the selective incorporation of oxygen. 

The fact that the epoxide yield decreases at higher temperatures, longer reaction time, higher catalyst concentration, and lower olefin concentration may be caused by two possible side reactions—decomposition of the hydroperoxide and addition of the alcohol to the epoxide. Initial kinetic studies of the decomposition of tert-butyl hydroperoxide in the presence of molybdenum hexacarbonyl showed second-order dependence on hydroperoxide and first-order dependence on catalyst concentration. These results indicate that the decomposition of hydroperoxide is caused by the reaction between the hydroperoxide-metal complex and another molecule of hydroperoxide. With higher temperature, higher... 

Tomida et al. (73) investigated the temperature-programmed desorption of n-butylamine from silica-alumina and alumina. The desorbed amine products were different in the two cases. n-Butylamine and n-butene were obtained from silica-alumina dibutylamine and n-butene were obtained from alumina. In a subsequent paper by Takahashi et al. (73a), the authors conclude that two types of adsorption sites on silica-alumina account for the desorption behavior of n-butylamine. One type chemisorbs the amine and the other catalyzes the decomposition of the amine to lower olefins at temperatures above 300°C. On the other hand, amine decomposition was not observed when pyridine was desorbed from silica-alumina. The effects of sodium poisoning on desorption behavior of n-butylamine and pyridine were also examined. 

These results were completely consistent with a rate-determining attack on the double bond to give an intermediate in which the stereochemistry about the olefinic bond is retained. Such a pathway is shown in Scheme 4. In such an hypothesis, an equivalent attack on the upper and the lower olefin faces would be expected, leading to equal yields of the two intermediates. Subsequent decomposition of these perepoxide intermediates would give the observed stereoiso-... 

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