Isobutylene diisobutylene

Sulfonated styrene—divinylbensene cross-linked polymers have been appHed in many of the previously mentioned reactions and also in the acylation of thiophene with acetic anhydride and acetyl chloride (209). Resins of this type (Dowex 50, Amherljte IR-112, and Permutit Q) are particularly effective catalysts in the alkylation of phenols with olefins (such as propylene, isobutylene, diisobutylene), alkyl haUdes, and alcohols (210) (see Ion exchange). Superacids. 

Pitch prevention agents for paper- Isobutylene, diisobutylene Japan 84,491 1980 Nippon Oils and Fats... 

Thickening agent—photographic Isobutylene, diisobutylene Japan 67,318 1975 Fuji Photo Film ... 

Di- and Triisobutylcncs. Diisobutylene [18923-87-0] and tnisobutylenes are prepared by heating the sulfuric acid extract of isobutylene from a separation process to about 90°C. A 90% yield containing 80% dimers and 20% trimers results. Use centers on the dimer, CgH, a mixture of 2,4,4-trimethylpentene-1 and -2. Most of the dimer-trimer mixture is added to the gasoline pool as an octane improver. The balance is used for alkylation of phenols to yield octylphenol, which in turn is ethoxylated or condensed with formaldehyde. The water-soluble ethoxylated phenols are used as surface-active agents in textiles, paints, caulks, and sealants (see Alkylphenols). 

Neopentanoic acid has also been produced commercially from diisobutylene [18923-87-0], in which the first step in the reaction sequence is a cracking or depolymeri2ation of the olefin to give isobutylene. 

The relationship between intrinsic viscosity [Tj] and mol wt for isobutylene polymers in diisobutylene is (79) ... 

This process produces polymer gasoline with a high octane. Dimerization was first used (1935) to dimerize isobutylene to diisobutylene, constituted of 2,4,4-trimethyl-1-pentene (80%) and 2,4,4-trimethyl-2-pentene (20%). Both phosphoric and sulfuric acid were used as catalysts. 

Isobutylene (CH2=C(CH3)2) is a reactive C4 olefin. Until recently, almost all isobutylene was obtained as a by-product with other C4 hydrocarbons from different cracking processes. It was mainly used to produce alkylates for the gasoline pool. A small portion was used to produce chemicals such as isoprene and diisobutylene. However, increasing demand for oxygenates from isobutylene has called for other sources. 

Isobutylene could be dimerized in the presence of an acid catalyst to diisobutylene. The product is a mixture of diisobutylene isomers, which are used as alkylating agents in the plasticizer industry and as a lube oil additive (dimerization of olefins is noted in Chapter 3). 

Sulfuric acid finds commercial application in the polymerization of isobutylene to diisobutylene (a mixture of the two 2,4,4-trimethylpen-tenes) and the copolymerization of isobutylene with the n-butylenes to obtain a more complex mixture of octylenes. Dilute (65-70 %) acid is used at 20-35° for the polymerization of only the isobutylene. The copolymerization occurs in the so-called hot acid polymerization process in which the dilute sulfuric acid is employed at about 80-90°. If more concentrated sulfuric acid is used, particularly acid of concentration above about 90%, conjunct polymerization occurs even at —35°. 

The formation of the other diisobutylene isomer is explained by assuming that isobutylene may also behave as H+ CH=r=C(CH3)2 ... 

In order to predict the formation of the isobutylene trimers, three alkenes may be considered to be activated, the original isobutylene and the two diisobutylenes. The various possibilities are shown in the following equations ... 

The reaction is run with excess ethylene to drive the equilibrium to product formation. The byproduct isobutylene is recycled to produce diisobutylene via dimerization (see Section 13.1.1). 

It seems certain that acid-catalyzed true oligomerization occurs via a carbocatio-nic mechanism as first suggested by Whitmore.5 Thus, the formation of diisobutylenes by dimerization of isobutylene in the presence of acidic catalysts occurs according to the following equation ... 

Butyl rubber is one product formed when isobutylene is copolymerized with a few percents of isoprene. In the Exxon process an isobutylene-methyl chloride mixture containing a small amount of isoprene is mixed at — 100°C with a solution of AICI3 in methyl chloride. An almost instantaneous reaction yields the product, which is insoluble in methyl chloride and forms a fine slurry. Molecular weight can be controlled by adding diisobutylene as a chain-transfer agent. Increased catalyst concentration and temperature also result in lowering molecular weight. The product can be vulcanized and is superior to natural rubber. A solution process carried out in C5-C7 hydrocarbons was developed in the former Soviet Union.471,472... 

Di- and Triisobutylenes. Diisobutylene [18923-87-0] and triisobutylenes are prepared by heating the sulfuric acid extract of isobutylene from a separation process to about 90°C. A 90% yield containing 80% dimers and 20% trimers results. Use centers on the dimer, a mixture of... 

Fig. 24. Dependences of the initial rate of TBA formation and ratio of DIP/TBA on H3PMo,2O40 concentration in the hydration of butenes. TBA, lerl-butyl alcohol DIB, diisobutylene. 357 K, isobutylene/1-butene = 1/1 (molar). (From Ref. 163.)...

The primary reactions in the alkylation of isobutane produce octanes from butylenes, heptanes from propylene, and nonanes from amylenes. Also, when dimer and trimer polymers of isobutylene are used with isobutane, the polymer is broken down during the reaction, and the resulting products are branched chain octanes similar to those produced when isobutylene is charged. Sulfuric acid consumption is somewhat higher for the diisobutylenes, however, and there are more side reactions than for isobutylene. 

Mitsubishi Rayon and Sumitomo Chemical in Japan make t-butylamine via the addition of hydrogen cyanide to isobutylene in acidic media, followed by hydrolysis of the resulting t-butylformamide [see Eq. (14.9)]. Average yields are about 85% based on isobutylene. Rohm and Haas in the United States makes t-octylamine from hydrogen cyanide and diisobutylene by a similar route116. 

To facilitate structure characterization, it was mandatory to minimize propagation. Thus a nonpolymerizable monomer was chosen, that is, an olefin which would undergo all the reactions of a polymerizable monomer (for example, isobutylene) except that it would not propagate. 2,4,4-Trimethyl-l-pentene (diisobutylene) was selected. This monomer is structurally closely related to isobutylene and due to its bulky substituents, it is unable to propagate. Model polymerization studies with this olefin could be viewed as polymerization without propagation . 

Alkylphenols are produced by reacting phenol with propylene or isobutylene oligomers. As shown in Figure 13.5, the reaction of a propylene trimer with phenol produces various isomers of nonylphenol, the most common feedstock for alkylphenol-based nonionic surfactants. Dimerization of isobutylene yields an octene which leads to octyl(diisobutylene)phenol. Similarly, propylene tetramer, on reaction with phenol, yields dodecyl(tetrapropylene)phenol. 

Isobutylene, CH2=C(CH3)2, is predominantly produced from cracked petroleum gases, and also, partially, by the dehydration of /-butanol. In industrial polymerizations, isobutylene is liquefied on addition of some diisobutylene, and mixed with about the same quantity of liquid ethylene and then cationically polymerized at -80°C with BF3/H2O. The diisobutylene acts as chain transfer agent and regulates the molar mass. The ethylene does not polymerize under these conditions on the other hand, it dissipates the heat of polymerization by volatilizing. 

MTBE is commercially produced by the reaction of isobutylene with methanol in the presence of an acidic ion-exchange resin as catalyst, usually in the liquid phase and at temperatures below 100°C. A typical catalyst is sulfonated styrene/divinylbenzene resin catalyst. Other solid acid catalysts such as bentonites are also effective and other novel catalysts have recently been discovered. Isobutylene is obtained from field butane by initial isomerization of n-butane to isobutane, followed by dehydrogenation to isobutylene. Commercial preparations of MTBE are 95.03 to 98.93% pure. Impurities are methanol (<0.43%), t-butyl alcohol (<0.80%), and diisobutylene (<0.25%). 

Olefins which undergo this reaction are 1-butene, 2-butene, isobutylene, a mixture of pentene isomers, diisobutylene, and tetrapropylene. Coffield et al. 82, 83) have shown that acetylene and manganese pentacarbonyl under 600 psi and at 150° C give l,2-(propenylene)cyclopentadienylmanganese tricarbonyl. The conditions of this synthesis are similar to those described by Reppe 84) for the reaction of acetylene with other metal carbonyls to form iT-bonded complexes. 

This process is used by Nan Ya Plastics Corporation to produce, starting from an isomer mixture of octene the alcohol, INA and has a capacity >100 000 mt/a. After 2-EH, INA is the most important plasticizer alcohol, which is a complex mixture of linear and branched Cg alcohols. The most important plasticizer produced from it is diisononyl phthalate (DINP). The raw material sources can be, for example, a Cg fraction from the extraction of Fluid Catalytic Cracking (FCC) C -based polygas, the product of dimerization of butene from a raffinate-2 fraction using the octol or dimersol process, or diisobutylene from the dimerization of isobutylene from raffinate-1. 

Especially isobutylene and diisobutylene are converted into pivalic acid and olefin cuts in the range of Q to into to CQ-carboxylic acid mixtures. This process employs CO pressures of about 70 atm and temperatures of 70 °C in the presence of H3PO4/BF3 as catalyst. Over 90% tertiary acids are obtained. 

Alkali-soluble resins Ethylene, propylene, diisobutylene, isobutylene, 2,4,-trimethyl-l-pentene United States 2,378,629 1945 DuPont ... 

Ethylene, propylene Isoprene, pentenes, methyl butenes, c/5-piperylene, trans-piperylene, cyclopentadiene Diisobutylene Isobutylene Isobutylene Isobutene... 

Paper coatings, rubber additives Diisobutylene, isobutylene, ethylene United States 4,048,442 1977 Bayer, Akt. 

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