Olefins gaseous

Introducing Ga into the framework produces profound changes in reactivity. The slcwer inductirai period observed for CSY zeolites is r laoed ty a rapid initial reaction (Fig 7). Both this initial rate and the subsequent rate increase with increase in Ga content i p to at least six Ga atoms per unit cell, the maximum substitution examined in the present work. This rapid initial rate is associated with the generation of considerable amounts of hydrogen and very olefinic gaseous products. In comparison with the CSY zeolites the [Ga/Al]-Y materials i cw increased d xosition of "coke". 

Commercial chlorohydrin reactors are usually towers provided with a chlorine distributor plate at the bottom, an olefin distributor plate about half way up, a recirculation pipe to allow the chlorohydrin solution to be recycled from the top to the bottom of the tower, a water feed iato the recirculation pipe, an overflow pipe for the product solution, and an effluent gas takeoff (46). The propylene and chlorine feeds are controlled so that no free gaseous chlorine remains at the poiat where the propylene enters the tower. The gas lift effect of the feeds provides the energy for the recirculation of the reaction solution from the top of the tower. 

Liquefied Petroleum Gas The term liquefied petroleum gas (LPG) is applied to certain specific hydrocarbons which can be liquefied under moderate pressure at normal temperatures but are gaseous under normal atmospheric conditions. The chief constituents of LPG are propane, propylene, butane, butylene, and isobutane. LPG produced in the separation of heavier hydrocarbons from natural gas is mainly of the paraffinic (saturated) series. LPG derived from oil-refinery gas may contain varying low amounts of olefinic (unsaturated) hydrocamons. 

Protection of an acetylenic hydrogen is often necessary because of its acidity. The bulk of a silane can protect an acetylene against catalytic hydrogenation because of rate differences between an olefin (primary or secondary) vs. the more hindered protected alkyne. Trialkylsilylacetylenes are often used as a convenient method for introducing an acetylenic unit because they tend to be easily handled liquids or solids, as opposed to gaseous acetylene. 

Upon thermolysis of xanthates (xanthogenates) 1 olefins 2 can be obtained, together with gaseous carbon oxysulfide COS 3 and a thiol RSH 4. This decomposition process is called the Chugaev reactionanother common transcription for the name of its discoverer is Tschugaejf. 

A higher steam/hydrocarhon ratio favors olefin formation. Steam reduces the partial pressure of the hydrocarbon mixture and increases the yield of olefins. Heavier hydrocarbon feeds require more steam than gaseous feeds to additionally reduce coke deposition in the furnace tubes. Liquid feeds such as gas oils and petroleum residues have complex polynuclear aromatic compounds, which are coke precursors. Steam to hydrocarbon weight ratios range between 0.2-1 for ethane and approximately 1-1.2 for liquid feeds. 

Increasing use of catalyst additives to reduce gaseous emissions and to maximize light olefins. 

Epoxides such as ethylene oxide and higher olefin oxides may be produced by the catalytic oxidation of olefins in gas-liquid-particle operations of the slurry type (S7). The finely divided catalyst (for example, silver oxide on silica gel carrier) is suspended in a chemically inactive liquid, such as dibutyl-phthalate. The liquid functions as a heat sink and a heat-transfer medium, as in the three-phase Fischer-Tropsch processes. It is claimed that the process, because of the superior heat-transfer properties of the slurry reactor, may be operated at high olefin concentrations in the gaseous process stream without loss with respect to yield and selectivity, and that propylene oxide and higher... 

According to [4], the optimum conditions of the sulfonation stage are a reactor temperature of 15°C, an S03/I0 ratio of 1.08, and 2.8 vol % S03 in the gas stream. Such mild conditions lead to sulfonation mixtures consisting of 85% P-sultones (1) 10% alkenesulfonic acids (2) 5% y-sultones (3) and less than 5% unreacted olefins. The authors observe that the reaction has been completed to more than 95% at the outlet of the reactor. This means that the incomplete conversions found by earlier authors [15] must have been due to phenomena occurring after the sulfonation. Of equal importance is the observation that the reactivity of 10 toward gaseous S03 seems similar to that of AO. 

Table 6 Ratios of Dibromides to Olefins in the Reactions of Bromohydrins with Gaseous HBr.

Other examples are given by the reaction of rra j-10-bromo-10,ll-dihydro-ll-hydroxy-5H-dibenz[b,f]azepine-5-carbonyl chloride with gaseous HBr in CCI4 to give the expected trans dibromide and the corresponding olefin in an about 3 7 ratio (Table 6) (ref. 20). The same reaction of 10-bromo-10,11-dihydro-11-... 

The catalytic degradation of polypropylene was carried out over ferrierite catalyst using a thermogravimetric analyzer as well as a fixed bed batch reactor. The activation of reaction was lowered by adding ferrierite catalyst, which was similar with that from ZSM-5. Ferrierite produced less gaseous products than HZSM-5, where the yields of i-butene and olefin over ferrierite were higher than that over HZSM-5. In the case of liquid product, main product over ferrierite is C5 hydrocarbon, while products were distributed over mainly C7-C9 over HZSM-5. Ferrierite showed excellent catalytic stability for polypropylene degradation. 

Selective oxidation and ammoxldatlon of propylene over bismuth molybdate catalysts occur by a redox mechanism whereby lattice oxygen (or Isoelectronlc NH) Is Inserted Into an allyllc Intermediate, formed via or-H abstraction from the olefin. The resulting anion vacancies are eventually filled by lattice oxygen which originates from gaseous oxygen dlssoclatlvely chemisorbed at surface sites which are spatially and structurally distinct from the sites of olefin oxidation. Mechanistic details about the... 

To test this theory, a mixture of n-hexane and Relabeled 1-hexene was reacted in hydrogen over the catalyst at various space velocities. The specific activity of each of the products (the n-hexenes were lumped together) are shown in Figure 2. The important observation is made at zero conversion. When extrapolated to Infinite space velocity, the benzene has approximately the same specific activity as the hexene, thus clearly indicating that essentially all the benzene is formed in a reaction sequence that involves equilibrium with gaseous n-hexenes. It may then be concluded that olefins are intermediates in the aromatiza-tion process. 

Other catalysts are 20% Na/C, 5% Li/AljOj or 10% Na/8% M0O3-AI2O3 or 10% NaH/Al203 [44]. Similarly, gaseous mixtures of olefins and NH3 have been claimed to give hydroaminated products over a ternary K/graphite/Al203 catalyst [45]. 

A lower molecular weight methyl ketone and an olefin are isolated as products of this reaction. That the enol is formed as a primary product which rearranges to the ketone follows from its detection in the IR spectrum of gaseous 2-pentanone upon photolysis. 3 In addition to the ketone and olefinic products, one usually obtains varying amounts of cyclobutanols. 

Excess diazomethane was used in all cases. Catalyst was Pd(OAc)2 if not stated otherwise. A Gaseous diazomethane added at 0 °C. — B Catalyst added to the solution of olefin and diazomethane/ether 0 °C. — C Gaseous diazomethane added at —10 to 0 °C to the solution of olefin in CH2C12 catalyst PdCl2 2 PhCN. — D Diazomethane/ether added at 0 °C to olefin and catalyst. 

The band at 1600 cm-1 due to a double-bond stretch shows that chemisorbed ethylene is olefinic C—H stretching bands above 3000 cm-1 support this view. Interaction of an olefin with a surface with appreciable heat suggests 7r-bonding is involved. Powell and Sheppard (4-1) have noted that the spectrum of olefins in 7r-bonded transition metal complexes appears to involve fundamentals similar to those of the free olefin. Two striking differences occur. First, infrared forbidden bands for the free olefin become allowed for the lower symmetry complex second, the fundamentals of ethylene corresponding to v and v% shift much more than the other fundamentals. In Table III we compare the fundamentals observed for liquid ethylene (42) and a 7r-complex (43) to those observed for chemisorbed ethylene. Two points are clear from Table III. First, bands forbidden in the IR for gaseous ethylene are observed for chemisorbed ethyl-... 

Importantly, the purple color is completely restored upon recooling the solution. Thus, the thermal electron-transfer equilibrium depicted in equation (35) is completely reversible over multiple cooling/warming cycles. On the other hand, the isolation of the pure cation-radical salt in quantitative yield is readily achieved by in vacuo removal of the gaseous nitric oxide and precipitation of the MA+ BF4 salt with diethyl ether. This methodology has been employed for the isolation of a variety of organic cation radicals from aromatic, olefinic and heteroatom-centered donors.174 However, competitive donor/acceptor complexation complicates the isolation process in some cases.175... 

Gaseous C3-C4 olefins, which constituted one-third of the syncrude, were oligomerized to liquid products, mainly in the naphtha boiling range, to boost motor gasoline production. 

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