Butenes from propylene

Independently from the results of ring-opening polymerization, Banks and Bailey [16] reported a disproportionation reaction of acyclic olefins, the formation of ethylene and 2-butene from propylene Eq. (2). 

OCT was originally developed by Phillips Petroleum and was first commercialized in 1965 when it was used to produce ethylene and butenes from propylene, due to the over-supply of the latter at that time. With the... 

This oxidation process for olefins has been exploited commercially principally for the production of acetaldehyde, but the reaction can also be apphed to the production of acetone from propylene and methyl ethyl ketone [78-93-3] from butenes (87,88). Careflil control of the potential of the catalyst with the oxygen stream in the regenerator minimises the formation of chloroketones (94). Vinyl acetate can also be produced commercially by a variation of this reaction (96,97). 

The propylene-based chemicals, n- and isobutanol and 2-ethyl-1-hexanol [104-76-7] (2-EH) dominate the product spectmm. These chemicals represent 71% of the world s total oxo chemical capacity. In much of the developed world, plasticizers (qv), long based on 2-EH, are more often and more frequendy higher molecular weight, less volatile Cg, and C q alcohols such as isononyl alcohol, from dimerized normal butenes isodecanol, from propylene trimer and 2-propyl-1-heptanol, from / -butenes and aldol addition. Because of the competition from the higher molecular weight plasticizer alcohols,... 

Figure 8-7. The Phillips Petroleum Co. process for producing 2-butene and ethylene from propylene (1) metathesis reactor, (2) fractionator (to separate propylene recycle from propane), (3, 4) fractionator for separating ethylene, butylenes, and Cg. ...

Olefin metatheses are equilibrium reactions among the two-reactant and two-product olefin molecules. If chemists design the reaction so that one product is ethylene, for example, they can shift the equilibrium by removing it from the reaction medium. Because of the statistical nature of the metathesis reaction, the equilibrium is essentially a function of the ratio of the reactants and the temperature. For an equimolar mixture of ethylene and 2-butene at 350°C, the maximum conversion to propylene is 63%. Higher conversions require recycling unreacted butenes after fractionation. This reaction was first used to produce 2-butene and ethylene from propylene (Chapter 8). The reverse reaction is used to prepare polymer-grade propylene form 2-butene and ethylene ... 

Isomerization of butene via a 7r-allyl species introduces an added dimension to the stereochemistry. The 7r-allyl species from propylene is presumed to be planar with its plane approximately parallel to the surface. Since it is attached to the electropositive zinc, it may have considerable carbanion character. A corresponding structure for adsorbed butene would lead to two isomeric forms, viz ... 

Firm assignments for these C=C bands require more detailed experiments but a tentative assignment can be made. The bands at 1550-1570 cm-1 are probably due to a ir-allyl species the shift from the double-bond region for butenes is about 100 cm-1 compared to the shift of 107 cm-1 observed for the 7r-allyl formed from propylene, but the butene is less firmly held. With propylene we observed a x-complex in which the shift in C=C stretch was about 30 cm-1. We believe the band at 1610 cm 1... 

Extension of the Kunii-Levenspiel bubbling-bed model for first-order reactions to complex systems is of practical significance, since most of the processes conducted in fluidized-bed reactors involve such systems. Thus, the yield or selectivity to a desired product is a primary design issue which should be considered. As described in Chapter 5, reactions may occur in series or parallel, or a combination of both. Specific examples include the production of acrylonitrile from propylene, in which other nitriles may be formed, oxidation of butadiene and butene to produce maleic anhydride and other oxidation products, and the production of phthalic anhydride from naphthalene, in which phthalic anhydride may undergo further oxidation. 

Product inspections and yield data for typical alkylates produced from propylene, butenes, and pentenes are presented in Table II. In general, the optimum operating con-... 

In 1959, Idol (2), and in 1962, Callahan et al. (2) reported that bismuth/molybdenum catalysts produced acrolein from propylene in higher yields than that obtained in the cuprous oxide system. The authors also found that the bismuth/molybdenum catalysts produced butadiene from butene and, probably more importantly, observed that a mixture of propylene, ammonia, and air yielded acrylonitrile. The bismuth/molybdenum catalysts now more commonly known as bismuth molybdate catalysts were brought to commercial realization by the Standard Oil of Ohio Company (SOHIO), and the vapor-phase oxidation and ammoxidation processes which they developed are now utilized worldwide. 

Statistically, the rate of formation of new olefins for Type II reactions, except in some cases involving branched olefins, is twice the rate for Type I reactions both alignments of the double-bond isomers to form the transition state will result in products different from the reactants. For Type III reactions three situations can exist depending on the reactants, both, only one, or neither alignment of the olefins will form a four-center transition state that dissociates into new olefins. Cleavage of 2-butene with propylene will not form new olefines however, cleavage of 2-butene with ethylene will form propylene. 

Beadle, S. W. Oligomerization process and catalyst system for preparing an oligomeric olefinic hydrocarbon mixture from propylene and butenes. WO Patent 2003082779,2003. 

Application To produce ethylene, propylene and butenes from natural gas or equivalent, via methanol, using the UOP/Hydro MTO (methanol to olefins) process. 

Meta-4 A process for converting ethylene and 2-butene into propylene by metathesis. The process operates in the liquid phase at low temperatures in the presence of heterogeneous catalyst based on rhenium oxide on alumina. The catalyst is constantly regenerated by coke combustion. Developed by IFP and the Chinese Petroleum Corporation of Taiwan. A demonstration plant was operated from 1988 to 1990 and the process was demonstrated at Kaohsiung, Taiwan, in 1999. Now offered by Axens. 

Diphenyl carbonate from dimethyl carbonate and phenol Dibutyl phthalate from butanol and phthalic acid Ethyl acetate from ethanol and butyl acetate Recovery of acetic acid and methanol from methyl acetate by-product of vinyl acetate production Nylon 6,6 prepolymer from adipic acid and hexamethylenediamine MTBE from isobutene and methanol TAME from pentenes and methanol Separation of close boiling 3- and 4-picoline by complexation with organic acids Separation of close-boiling meta and para xylenes by formation of tert-butyl meta-xyxlene Cumene from propylene and benzene General process for the alkylation of aromatics with olefins Production of specific higher and lower alkenes from butenes... 

Thus, the most direct route to chain-carrying, tertiary butyl carbonium Ions is offered in isobutene-isobutane alkylation (Equation I). When initiating with either a linear butene or propylene, a second step is necessary to form the tertiary butyl carbonium ion, i.e., abstraction of a hydride Ion from an isobutane molecule while forming a molecule of normal alkane. (Equation 2, 2-A, 3, 3-A). Reaction sequences in these equations are often referred to as hydrogen- or hydride transfer reactions and will be discussed subsequently. 

If alkylation were a selective process, one would expect to obtain 23DMP from propylene, 23DMH from 1-butene, 224TMP from Isobutene and diisobutene, and a mixture of TMP s from cis- or trans-2-butene. (, , 7 ) These are the products which predominated at 4 C. The many other products listed in Tables I and II are the result of the various side reactions which accompany alkylation. At 45 C, the yield of primary alkylation products was greatly reduced. Alkylation yielded increased amounts of 24DMP and 224 IMP from propylene, mixed IMP s from 1-butene, DMH s from the other C4 olefins, and heavy and light ends from all feedstocks. Thus, as the reaction temperature was Increased, side reactions became increasingly important. 

As with the pure olefin feeds, lowering the reaction temperature Inhibited side reactions. The yield of primary alkylation products such as 23DMH and 23DMP Increased, as the formation of other DMH Isomers and 24DMP was Inhibited. TMP s are both a primary product and a byproduct. Thus, TMP s from Isobutene and 2-butene Increased as TMP s from propylene and 1-butene decreased. The total TMP yield was optimized at 27 C. 

The normal butenes were pyrolyzed in the presence of steam in a nonisothermal flow reactor at 730°-980°C and contact times between 0.04 and 0.15 sec to obtain conversion covering the range between 3% and 99%. Isomerization reactions accompanied the decomposition of these olefins however, the decomposition was the dominant reaction under these conditions. Pyrolysis of 1-butene is faster than that of either cis- or trans-2-butene. Methane, propylene, and butadiene are initial as well as major products from the pyrolysis of the n-butenes. Hydrogen is an initial product only from the 2-butenes. Ethylene appears to be an initial product only from 1-butene it becomes the most prominent product at high conversions. Over the range of conditions of potential practical interest, the experimental rate expressions for the disappearance of the respective butene isomers, have been derived. 

For both feeds, propylene and butadiene are the major products obtained. The order of their production, however, appears to depend on the structure of the feed olefin. Thus, butadiene is the single, most prevalent product from the 2-butenes while propylene is predominant from 1-butene. A similar reversal in relative yield can be noted for the Ci/C2 products. Over the entire conversion range, the combined yields of butadiene and ethylene are approximately equal to the combined yields of propylene and methane for both starting olefins. 

Employing a somewhat similar approach. Paiaro and Panunzi and co-workers (137, 455, 458, 459, 462) have shown that diastereoisomeric pairs are produced when an olefin which does not contain symmetry planes perpendicular to the plane of the double bond and an optically active ligand such as a-phenylethylamine are coordinated to plati-num(II). When a double bond is coordinated to the metal atom, each of the trigonal carbon atoms, if already linked to two different substituent groups, becomes an asymmetric center. One would thus expect to obtain two diastereoisomers from propylene, styrene, or meso compound would be expected since the two asymmetric carbon atoms have opposite configuration. 

From previously reported studies then, several different products are possible. The initial attack by the oxygen moiety may apparently be vinylic (on either of the two carbons of the double bond) or allylic (on the carbon next to the doubly bonded carbons). Distinction must be made between allylic attack as described here and allylic products which can arise either by true allylic attack or by vinylic attack followed by olefinic isomerization. Thus it is not clear whether such products as 2-hexen-l-yl acetate(II) (58) have been formed by vinylic attack upon hexene followed by olefinic isomerization, by olefin isomerization of hexene to 2-hexene followed by allylic attack, or by some type of synchronous mechanism in which oxygen attack and olefin isomerization occur simultaneously. This last possibility could be visualized as involving some type of 7r-allylic complex (Reaction 2). This involvement of TT-allylic complex can be ruled out only in the production of isopropenyl acetate from propylene since a mechanism such as this followed by olefin isomerization could not be used in that case. For the butenes and higher... 

---