Amylene

The f-amylene is dehydrogenated to isoprene, which is used to produce isoprene-based rubbers that include IR, ilR, SIS (TPE), and ilR that is used to make PP/iiR thermoplastic vulcanizate (TPV). 

Rubicon s Geismar, LA, plant is currently the largest aniline plant in North America. BASF at Geismar, LA, is the second largest aniline plant in North America. 

DuPont has a plant at Beamont, TX, while First Chemical owns two aniline plants, one in Baytown, TX, and the other in Pascagoula, MS. First Chemical is a subsidiary of DuPont and expanded the Beamont, TX, plant s capacity. The United States has a production capacity of over 2 billion pounds per year. 

Over 85% of the production of aniline goes into the synthesis of MDI for polyurethane elastomers and polyurethane rigid foams. Therefore, MDI capacity increases are the driving force for aniline capacity increases. The big growth area now for MDI is with rigid foam production, used mainly in construction. Over one-half of MDI production is used to make rigid foams. 

About 8% of aniline production goes directly into the manufacture of rubber accelerators and antioxidants. Aniline is reacted with carbon disulfide to produce crude mercaptobenzothiazole (MBT), which is purified further for use as a rubber accelerator. More importantly, MBT is an intermediate for the manufacture of other, more sophisticated accelerators. 

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Amylene is a general name for the ethylenic hydrocarbons of the molecular formula CjHio. Two of these hydrocarbons are the main products of the dehydration of the appropriate amyl alcohols ... 

A little sulphurous acid may be present. This may be removed by transferring the product to a separatory funnel, shaking gently with 5 ml. of 10 per cent, sodium hydroxide solution (the pressure should be released from time to time by inverting the funnel and turning the stopcock), followed by water. This purihca tion is unnecessary if the amylene is only to be used ibr the experiments in Section 111,11. 

Carry out the following tests with the sample of amylene prepared in Section 111,10 (compare Section III,6). 

Cool 1 ml. of amylene in ice and add 1 ml. of cold, dilute sulphuric acid (2 acid 1 water), and shake gently until the mixture is homogeneous. Dilute with 2 ml. of water if an upper layer of the alcohol does not separate immediately, introduce a little sodium chloride into the mixture in order to decrease the solubility of the alcohol. Observe the odour. The unsaturated hydrocarbon is thus largely reconverted into the alcohol from which it may be prepared. 

The alicyclic secondary alcohol, cycZohexanol, may be dehydrated by concentrated sulphuric acid or by 85 per cent, phosphoric acid to cyciohexene. It has a higher boiling point (82-83°) than amylene and therefore possesses some advantage over the latter in.the study of the reactions of unsaturated hydrocarbons. 

Bromopentane. Proceed as for n-Amyl Bromide, but use 88 g. (108 ml.) of methyl n-propyl carbinol (2-pentanol), b.p. 118-5°. During the washing with concentrated hydrochloric acid, difficulty may be experienced in separating the acid layer this is overcome by adding a little water to decrease the density of the acid. Distil the purified product through a fractionating colunm some amylene passes over first, followed by the 2-bromopentane at 115-118° (120 g.). 

Blends of piperylenes and amylenes (mixed 2-methyl-1-butene and 2-methyl-2-butene) or UOP propylene dimers can be adjusted to produce softening points of 0—100°C and weight average molecular weights of <1200 (32,33). Careful control of the diolefin/branched olefin ratio is the key to consistent resin properties (34). 

Dehydrogenation of Tertiary Amylenes, The staiting material here is a fiaction which is cut from catal57tic clacking of petroleum. Two of the tertiary amylene isomers, 2-methyl-l-butene and 2-methyl-2-butene, are recovered in high purity by formation of methyl tertiary butyl ether and cracking of this to produce primarily 2-methyl-2-butene. The amylenes are mixed with steam and dehydrogenated over a catalyst. The cmde isoprene can be purified by conventional or extractive distillation. 

All lation. The combination of olefins with paraffins to form higher isoparaffins is termed alkylation (qv). Alkylate is a desirable blendstock because it has a relatively high octane number and serves to dilute the total aromatics content. Reduction of the olefins ia gasoline blendstocks by alkylation also reduces tail pipe emissions. In refinery practice, butylenes are routinely alkylated by reaction with isobutane to produce isobutane—octane (26). In some plants, propylene and/or pentylenes (amylenes) are also alkylated (27). 

Alkylate is composed of a mixture of isoparaffins whose octane numbers vary with the olefins from which they were made. Butylenes produce the highest octane numbers, propylene the lowest, and amylenes (pentylenes) the iatermediate values. AH alkylates, however, have high (>87) octane numbers that make them particularly valuable. 

Propylene, butylenes, or amylenes are combiaed with isobutane ia the presence of an acid catalyst, eg, sulfuric acid or hydrofluoric acid, at low temperatures (1—40°C) and pressures, 102—1035 kPa (1—10 atm). Sulfuric acid or hydrogen fluoride are the catalysts used commercially ia refineries. The acid is pumped through the reactor and forms an emulsion with reactants, and the emulsion is maintained at 50% acid. The rate of deactivation varies with the feed and isobutane charge rate. Butene feeds cause less acid consumption than the propylene feeds. 

Amylenes. Amylenes (C monoolefins) produce alkylates with a research octane in the range of 90—93. In the past, amylenes have not been used widely as an industrial alkylation charge, although in specific instances, alkylation with amylenes has been practiced (23). In the future, alkylation with amylenes will become more important as limits are placed on the vapor pressure and light olefin content of gasolines. 

Alkylate. Alkylation means the chemical combination of isobutane with any one or a combination of propylene, butylenes, and amylenes to produce a mixture of highly branched paraffins that have high antiknock properties with good stabiUty. These reactions are cataly2ed by strong acids such as sulfuric or hydrofluoric acid and have been studied extensively (98—103). In the United States mostly butylenes and propylene are used as the olefins. 

Pentanone, see Diethyl ketone Pentene, see Amylene n-Pentyl acetate, see n-Amyl... 

Chemical Designations - Synonyms alfa-n-Amylene Propylethylene Chemical Formula CH3(CHi)2CH=CHi. 

To obtain light ends conversion, alkylation and polymerization are used to increase the relative amounts of liquid fuel products manufactured. Alkylation converts olefins, (propylene, butylenes, amylenes, etc.), into high octane gasoline by reacting them with isobutane. Polymerization involves reaction of propylene and/or butylenes to produce an unsamrated hydrocarbon mixture in the motor gasoline boiling range. 

Chloroform HPLC solvent hydrocarbon stabilized GR LiChrosolv for analysis Chromasolv ethanol, 0.5 to 1% amylene, 0.01 to 0.02% ethanol, 0.6 to 1.0% amylene ethanol, ca. 1% amylene Baker Baker Merck Merck RiEDEL-de Haen RiEDEL-de Haen... 

Isoprene is the second important conjugated diene for synthetic rubber production. The main source for isoprene is the dehydrogenation of C5 olefins (tertiary amylenes) obtained by the extraction of a C5 fraction from catalytic cracking units. It can also be produced through several synthetic routes using reactive chemicals such as isobutene, formaldehyde, and propene (Chapter 3). 

Deep catalytic cracking (DCC) is a catalytic cracking process which selectively cracks a wide variety of feedstocks into light olefins. The reactor and the regenerator systems are similar to FCC. However, innovation in the catalyst development, severity, and process variable selection enables DCC to produce more olefins than FCC. In this mode of operation, propylene plus ethylene yields could reach over 25%. In addition, a high yield of amylenes (C5 olefins) is possible. Figure 3-7 shows the DCC process and Table 3-10 compares olefins produced from DCC and FCC processes. ... 

The first step involves dehydrogenation of the butanes to a mixture of butenes which are then separated, recycled, and converted to butadiene. Figure 3-16 is the Lummus fixed-bed dehydrogenation of C4 mixture to butadiene. The process may also be used for the dehydrogenation of mixed amylenes to isoprene. In the process, the hot reactor effluent is quenched, compressed, and cooled. The product mixture is extracted unreacted butanes are separated and recycled, and butadiene is recovered. 

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