Butene/3-methylbutene

Synonyms EINECS 209-249-1 Isopentene Isopropylethene Isopropylethylene a-Isoamylene 2-Methyl-3-butene 3-Methylbutene UN 2561 Vinyl isopropyl. 

One of the features of olefin copolymerization kinetics is the effect of comonomer on the rate of ethene or propene polymerization during ethene/a-olefin or propene/ a-olefin copolymerization, i.e., the so-called comonomer effect (CEF). The rate enhancement of ethene or propene polymerization in the presence of a comonomer is observed for conventional ZN catalysts [80, 113-123] and for homogeneous [124-133] and supported metallocenes [134—136] and post-metallocenes catalysts [137-140]. The increase in activity was remarked in the presence of such comonomers as propene, 2-methylpropene, 1-butene, 3-methylbutene,4-methylpentene-l, 1-hexene, l-octene,l-decene, cyclopentene, styrene, and dienes. 

Copolymers of different monomeric units that are able to co-crystallize in the same lattice are classic examples of polymer crystals including disorder due to isomorphic substitution of monomeric units in the crystal lattices. This occurs for instance for isotactic butene-3-methylbutene [3] or styrene-o-fluorostyrene [4] copolymers and isotactic [5-8] and syndiotactic [9, 10] propene-butene copolymers, which are crystalline in the whole range of compositions. In these cases the constitutional disorder due to the presence of mono-... 

The aliphatic mono-olefins present a particularly complicated picture at first sight. Only a few of them will give high polymers by cationic catalysis most of these are either 1,1-disubstituted ethylenes, or ethylenes with a single branched substituent, such as 3-methylbutene-1 and vinylcyclohexane. The reasons why ethylene, propene, and the n-butenes do not give high polymers have been set out in detail [71]. Briefly, the ions derivable directly from all of these are either primary or secondary, e.g.,... 

A. Turner Jones. Crystalline phases in copolymers of butene and 3-methylbutene , J. Polym. ScL, Polym. Lett. Ed. 3, 591 (1965). J. Polym. ScL, Part B Polym. Lett. 

Doering and Prinzbach20 photolyzed CH2N2 in the presence of 2-methylpropene 1-14C in the liquid phase and in the gas phase at 400 mm. The product ratios (Table II) in the liquid were quite similar to the high pressure values of Frey and Knox et al., although Doering and Prinzbach also report no 3-methylbutene-l. The chief object of this work was to study the mechanism of the insertion reaction of methylene into CH bonds. The product 2-methyl-butene-l, which is formed entirely by insertion and not by isomerization, was separated from the reaction... 

Butene-2. The experimental results for the reaction of methylene with cis and trans butene-2 are summarized in Table III. In the liquid phase and in the gas phase at high pressures (>200 mm.) the major products are 1,2-dimethylcyclopropane (addition to double bond), pentane-2, and 2-methylbutene-2 (insertion products), and the steric configuration of the butene-2 is predominantly retained in the products... 

Decreased deactivation efficiency may also account for changing product ratios, such as increased formation of 3-methylbutene-l. Although Frey found no 3-methylbutene-l in photolysis experiments without added argon, this product was reported by Setser and Rabinovitch in pyrolysis of CH2N2-butene-2 mixtures and is also found to some extent in the thermal decomposition of 1,2-dimethylcyclopropane. It appears, therefore, that the formation of 3-methylbutene-l depends more on reaction conditions than on the electronic state of CH2. 

The amides of alkali and alkaline-earth metals catalyse hydrogen exchange in hydrocarbons even in the absence of liquid ammonia. For example, the heterogeneous deuterium exchange of benzene and 2-methylbutene-l occurs with a considerable velocity on solid KND2 and Ca(ND2)2 at 70°. This gives rise to the isomerization of 2-methyl-butene-1 to 2-methylbutene-2 (Shatenshtein et al., 1958a). 

This conclusion is supported by observations of the isomerization of unsaturated hydrocarbons catalysed by potassium amide not only in ammonia solution (Shatenshtein and Vasil eva, 1954 Shatenshtein et al., 1954) but also by solid amides of alkali and alkaline-earth metals (Shatenshtein et al., 1958a). For example, diallyl rearranges to dipropenyl, pentene-1 to pentene-2, and 2-methylbutene-l to 2-methyl-butene-2. Subsequently, a further number of examples of isomerization... 

Methylbutenes 2-Pentenes i Pentene Pentanes 2-Methylbutane 2-Butenes Isobutylene J Butanes Propylene Propane Ethane Methane 5 Hydrogen 0... 

SYNS tert-AMYLENE ISOPENTENE ISOPENT-ENES pOT) METHYLBUTENE 2-METHYL-BUTENE... 

Zaspalis et al. [1991b] and Bitter [1988] utilized alumina membrane reactors containing Pt catalysts to examine dehydrogenation of n-butane to butene and 2-methylbutenes to isoprene, respectively. Both the conversion and selectivity improved by using the membrane reactors. The increase of conversion is about 50% in both cases. Moreover, Suzuki [1987] used stainless steel membranes and Pi or CaA-zeolite layer catalysts to perform dehydrogenation of isobutene and propene to produce propane. 

Studies on the photolysis of butene-1 at 1849 A have been made by Harumiya et and by Borrell and Cashmore . Ethane and 1,5-hexadiene are the most important products. Borrell and Cashmore report a total of twenty-five products which in addition to the ethane and 1,5-hexadiene include methane, ethylene, acetylene, propene, propane, allene, cis- and franj-butene-2, 3-methylbutene, n- and isopentane, cis- and fra j-pentene-2, pentene-1, as well as various Cg, C and Cg compounds. The following reactions explain these products. 

Major yields of propene (ca. 10%) are found in the initial products from isobutene oxidation between 673 and 773 K, but effectively no propene is observed initially from the oxidations of butene-1, 2-methylbutene-2 and 2,3-dimethylbutene-2. Structurally, propene formation is possible via C3H7 radicals in all cases through the hydroxy adduct. 

The direction of elimination from esters has been extensively studied (DePuy and King, 1960). In general, where special structural features are absent, olefin with the smallest number of alkyl substituents is most abundant. Thus from s-butyl acetate 60% of butene-1 is produced, while from t-pentyl acetate, 2-methylbutene-l occurs to the extent of 75%. In distinction to the halides, which, as has been seen, give the Saytzeff product, the esters give predominately the Hofmann product. This may in part be due to the fact that the carboxylic acid which is found along with the olefin, is not capable of bringing about isomerization, as can the hydrogen halide in the case of the alkyl halides. 

Vapor-phase aerobic oxidations of lower olefins, e. g. propylene to acrolein or acrylic acid and isobutene to methacrolein or methacrylic acid, are well-established bulk chemical processes [1,2], They are usually performed over oxidic catalysts, such as bismuth molybdate or heteropoly compounds, although the scope of these allylic oxidations is limited to olefins that cannot form 1,3-dienes via oxidative dehydrogenation. Thus 1- and 2-butene are converted to butadiene, and methylbutenes to isoprene, and with higher olefins complex mixtures result from further oxidation. Hence, such methodologies are not relevant in the context of fine chemicals. 

Fig. 5.1. Chromatograms of products of catalytic cracking (A) without reactor and (B) with reactor. Sorbent, 11% quinoline on refractory brick temperature, 25 C column length, 10.5 m. Peaks 1 = propane 2 = propylene 3 = isobutane 4 = n-butane 5 = isobutene 6 = butene-1 7 = rmns-butene-2 8 = cis-butene-2 9 = isopentane 10 = 3-methylbutene-l 11 = n-pentane 12 = pentene-1 13 = 2,2-dimethylbutene 14 = 2-methylbutene-l 15 = tnms-pentene-2 16 = cfsi)entene-2 17 = 2-methyl-butene-2 18 = 2,3-dimethylbutane 19 = 2-methylpentane 20 = 3-methylpentane 21 = 3-methylpen-tene-1 22 = 4-methylpentene-l 23 = c -4-methylpentene-2 24 = cyclopentane 25 = 2,3-dimethyl-butene-1 26 = fmns-4-methylpentene-2 27 = w-hexane 28 = cyclopentene 29 = 2-methylpentene-l 30 = hexene-1 31 = 2,4-dimethylpentane 32 = cis-hexene-3 33 = tnms-hexene-3 34 = 2-ethylbu-tene-1 35 = trans-hexene-2 36 = methylcyclopentane 37 = cis-methylpentene-2 38 = 2-methylpen-tene-2 39 = pisns-3-methylpentene-2 40 = methylcyclopentene-4 41 = 4-methylcyclopentene 42 = cw-3-methylpentene-2 43 = 2,3-dimethylpentane 44 = 2-methylheptane 45 = 2,3-dimethylbutene-2 46 = methylheptane 47 = cyclohexane 48 = C, olefin. Reprinted with permission from ref. 1.

Orcinol upon treatment dropwise with 2-methyl-3-buten-2-ol in warm aqueous formic acid at 80°C and reaction for 1 hour afforded 5-methyl-4-(3-methylbuten-2-yl)resorcinol in low yield while from the filtrate of the reaction mixture, the isomeric compound, 5-methyl-2-(3-methylbuten-2-yl)resorcinol was isolated as well as a bis-prenyl compound by chromatographic purification (ref.16). 

Polyolefin copolymers started with LLDPE and ethylene-propylene rubber (EPR). Today, there are polyolefin copolymers of ethylene with butene-1, hexene-1, octene, cyclopentene, and norbornene and copolymers of propylene with butene-1, pentene-1, and octene-1 in addition to ethylene. There are copolymers of butene-1 with pentene-1, 3-methylbutene-l, 4-methylpentene-1, and octene in addition to its copolymers with ethylene and propylene. There are copolymers of 4-methylpentene-1 with pentene-1 and hexene-1 in addition to its copolymers with butene-1 and propylene. The function of the comonomers is to reduce crystallinity, as compared to the homopolymers, resulting in copolymers that are highly elastomeric with very low... 

The IR spectrum and NMR spectral data for 2-chloro-2-methylbutane, 2-methyl-2-butanol, 2-methyTl-butene, and 2-methyl-2-methylbutene are provided in Figures 14.7,14.8,14.5, 14.6, and 10.4r-10.7, respectively. 

This section contains experimental results relating to the structure of different copolymers of high olefins. All data are listed under the main olefins used for copolymerization ethylene, propylene, butene-1, 3-methylbutene-l, 4-methyIpentene-l, and styrene. When such a classification is used, it is inevitable that some copolymers will be mentioned twice (e.g. ethylene-styrene and styrene-ethylene copolymers). Where this occurs, the data on copolymer structures are given under the first... 

The examination of rj t2 values for hundreds of different comonomers polymerized by different mechanisms (2) reveals that in the overwhelming majority of cases these r, r2 values are close to or less than 1 very few examples of ionic processes were found with rjr2>l (J69). For this reason the appearance of a significant number of cases with rir2>t can be regarded as characteristic of complex catalysis. The mentioned tendency is especially pronounced when the comonomers have alkyl groups of different size (ethylene—4-methylpentene-l, pro-pyIene-butene-1, propylene-styrene, propylene-4-methylpentene-l, pro-pylene-vinylcyclohexane). On the other hand, when the alkyl groups are of similar bulkiness (4-methylpentene-l-vinylcyclohexane, 4-methyl-pentene-l-3-methylbutene-l, vinylcyclohexane-styrene), the copolymers obtained are mainly random or have a tendency to alternation. 

In this context it is of interest that Lutz and Bailey 22) sdectively polymerized pentene-1 to a solid polymer in the presence of 2-methyl-butene-1 with AIEts/TiClg (Al/Ti=2) catalyst and that the 2-methyl-butene-1 isomerized to 2-methylbutene-2 during the coiurse of the polymerization. 

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