Propane polymerization

Polymerizations slurry polymerization is achieved in the same conditions preyiously described for propane polymerization a >, except temperature 80 C, total pressure 8 bars. 

In a previous study / we. performed propane polymerization using an Et(Ind)aHfCI a / MAO catalyst system. Some of the data... 

Liquefied gas fractions (propane, propylene, butanes, butenes) that will be able to provide feedstocks to units of MTBE, ETBE, alkylation, dimerization, polymerization after sweetening and/or selective hydrogenation. 

As an example of the quantitative testing of Eq. (5.47), consider the polymerization of diethylene glycol (BB) with adipic acid (AA) in the presence of 1,2,3-propane tricarboxylic acid (A3). The critical value of the branching coefficient is 0.50 for this system by Eq. (5.46). For an experiment in which r = 0.800 and p = 0.375, p = 0.953 by Eq. (5.47). The critical extent of reaction, determined by titration, in the polymerizing mixture at the point where bubbles fail to rise through it was found experimentally to be 0.9907. Calculating back from Eq. (5.45), the experimental value of p, is consistent with the value =0.578. 

It has been observedt that poly(1,1-dimethyl propane) is the product when 3-methylbutene-l is polymerized with AICI3 in ethyl chloride at -130°C. Write structural formulas for the expected repeat units and those observed and propose an explanation. 

Thermal polymerization is not as effective as catalytic polymerization but has the advantage that it can be used to polymerize saturated materials that caimot be induced to react by catalysts. The process consists of the vapor-phase cracking of, for example, propane and butane, followed by prolonged periods at high temperature (510—595°C) for the reactions to proceed to near completion. Olefins can also be conveniendy polymerized by means of an acid catalyst. Thus, the treated olefin-rich feed stream is contacted with a catalyst, such as sulfuric acid, copper pyrophosphate, or phosphoric acid, at 150—220°C and 1035—8275 kPa (150—1200 psi), depending on feedstock and product requirement. 

After epoxidation, propylene oxide, excess propylene, and propane are distilled overhead. Propane is purged from the process propylene is recycled to the epoxidation reactor. The bottoms Hquid is treated with a base, such as sodium hydroxide, to neutralize the acids. Acids in this stream cause dehydration of the 1-phenylethanol to styrene. The styrene readily polymerizes under these conditions (177—179). Neutralization, along with water washing, allows phase separation such that the salts and molybdenum catalyst remain in the aqueous phase (179). Dissolved organics in the aqueous phase ate further recovered by treatment with sulfuric acid and phase separation. The organic phase is then distilled to recover 1-phenylethanol overhead. The heavy bottoms are burned for fuel (180,181). 

In the depropanizer tower the propane and lighter gases are taken overhead to become feed to the ethylene and propylene recovery facilities. Separation is accomplished at a relatively low overhead temperature of -25°F to minimize reboiler fouling by olefin polymerization. 

Projections, linearly independent, 293 Propagation, of polymerization, 158 Propane, hydrate, 10, 33, 43, 46, 47 hydrate thermodynamic data and lattice constants, 8 + iodoform system, 99 Langmuir constant, 47 water-hydrogen sulfide ternary system, 53... 

B. Polymeric Urea [Benzene, diethenyl-, polymer with ethenylbenzene, [[[[(1 methylethyl)amino]carbonyt]amino]methyl] deriv.] A 10.0-g. portion of benzylamine polymer beads prepared as in Part A and 125 ml. of tetrahydrofuran (Note 6) are combined in a 300-ml., three-necked, round-bottomed flask equipped with a magnetic stirrer, a dropping funnel, and a condenser fitted with a gas-inlet tube A nitrogen atmosphere is established in the system, and the slurry is stirred while 1.35 g. (0.0159 mole) of isopropyl isocyanate [Propane, 2-isocyanato-] is added. This causes an exothermic reaction, which subsides after about 20 minutes. The mixture is then stirred at room temperature for 22 hours and at reflux for an additional 4 hours. The beads are collected by filtration, washed with 150-ml. portions of tetrahydrofuran (Note 6) and methanol, and dried under reduced pressure over calcium chloride to yield 9.09 g, of the isopropyl urea polymer. 

Pure (A)-1 -chloropropene was obtained by careful distillation of a mixture of (E)- and ( )-l -chloropropene (available from Columbia Organic Chemicals Company Inc.) using a Nester-Faust Teflon annular spinning band column [(Z)-l-chloropropene has b.p. 33° (A)-l-chloropropene has b.p. 37°]. Small quantities of powdered sodium bicarbonate and hydroquinone (1,4-benzenediol) placed in the distillation flask inhibit acid-catalyzed isomerization and polymerization. Gas chromatographic analysis of the material used in these experiments on a 4-m., 15% l,2,3-tris(2-cyanoethoxy)propane (TCEP) on Chromosorb P column, operated at room temperature, typically indicated that it had isomeric purity >99.9%. (A)- 1-Chloropropene is stable for several months at room temperature, but it should be stored in a cool place. 

Tetrapropylene is manufactured from propylene (containing 50% propane) with the use of a phosphoric acid catalyst at 70-bar pressure and 200°C. Under these conditions a product mixture is obtained which has to be purified by distillation. Unconverted propane is obtained as the first fraction, followed by tripropylene which can either be sent back to the polymerization or used as motor fuel. The third fraction consists of the desired tetrapropylene. 

A star copolymer (SCP) of PCLA was synthesized by Younes and coworkers. This kind of SCP PCLA elastomer was also synthesized in two steps. First, the small molecular SCP was produced by ring-opening polymerization of s-caprolactone (s-CL) with glycerol as initiator and stannous 2-ethyUiexanoate as catalyst. Second, the living SCP was further reacted with different ratios of a cross-linking monomer, such as 2,2-bis(s-CL-4-yl)-propane (BCP) and s-CL. The SCP elastomers had very low glass transition temperature (—32°C). It was reported that the SCPs were soft and weak with physical properties similar to those of natural bioelastomers such as elastin. A logarithmic decrease in each tensile property with time was observed in this SCP PCLA. 

The most common poly(alkenoic acid) used in polyalkenoate, ionomer or polycarboxylate cements is poly(acrylic acid), PAA. In addition, copolymers of acrylic acid with other alkenoic acids - maleic and itaconic and 3-butene 1,2,3-tricarboxylic acid - may be employed (Crisp Wilson, 1974c, 1977 Crisp et al, 1980). These polyacids are prepared by free-radical polymerization in aqueous solution using ammonium persulphate as the initiator and propan-2-ol (isopropyl alcohol) as the chain transfer agent (Smith, 1969). The concentration of poly(alkenoic add) is kept below 25 % to avoid the danger of explosion. After polymerization the solution is concentrated to 40-50 % for use. 

Denver, Colorado (Refs. 16 and 19) 3 (0 in buildings) A propane release at a polymerization unit in a process plant resulted in a blast that destroyed the process unit. The blast-resistant control house, located only 98 ft (30 m) from the blast center, sustained little damage. 

Silver(I) complexes with polyamines also form molecular aggregates, thus hexamethylenetetramine yields 2D and 3D coordination networks,613 polymeric chains are obtained with diethylene-triamine, tris(2-aminoethyl)amine, or A,A -bis(aminoethyl)propane-l,3-diamine,426 and 2D networks are formed with thiocyanate and bridging polyamines.61... 

Thia-crown ethers incorporating propan-2-one units and dimeric silver(I) compounds as (176) and other polymeric species have been prepared.1132,1133 Other substituents can be diisopropyl idene groups which form complexes of the type [AgL(PPh3)]OTf (177),1134 pyridazine,1133 phthalazine1136 ligands or even organometallic compounds as ferrocene in (178).1137... 

Bisphenol A, whose official chemical name is 2,2-bis(4-hydroxyphenyl)propane, is a difunctional monomer with two reactive hydroxyl groups, as shown in Fig. 20,2. It polymerizes svith dicarbonyl organic monomers, such as phosgene or diphenyl carbonate, which are illustrated in Fig. 20.3. During polymerization, shown in Fig. 20.4, the hydroxyl groups of the bisphenol A deprotonate in the presence of a base. After deprotonation, the oxygen atoms on the bisphenol A residue form ester bonds with the dicarbonyl compounds. The polymerization process terminates when a monohydric phenol reacts with the growing chain end. 

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