Propyne, polymerization

Mo2(0R)6 compounds in hydrocarbon solvents rapidly polymerize acetylene to a black metallic-looking form of polyacetylene. Propyne is polymerized to a yellow powder, while but-2-yne yields a gelatinous rubber-like material (45). The detailed nature of these polymers is not yet known and the only molybdenum containing compounds recovered from these polymerization reactions were the Mo2(0R)6 compounds. When the reactions were carried out in the presence of pyridine/hexane solvent mixtures, simple adducts Mo2(0R)6(py)2(ac) were isolated for R = i-Pr and CH2-t-Bu, and ac = HCCH, MeCCH and MeCCMe (45,46). 

In 1975, it was discovered that WCk, which is a typical metathesis catalyst, is capable to catalyze the polymerization of phenylacetyl-ene. Subsequently, various substituted acetylenes have been polymerized by this type of catalyst. In 1983, poly(l-(trimethylsilyl)-l-propyne)) was synthesized in the presence of Tads and NbCls (35). The alkyne polymerization has many similarities with ROMP. 

Allyl Type Alcohols, Polymerized. See under Polymerized Alcohols Aliyiene(Propyne or Propine), CH3. C CH, mw 40.06- Gas, mp -102.7°, bp -23.2° SI sol in w, sol in ale eth. Its toxicity and fire Si expln hazards are discussed in Ref 3 It was reported that an expln occurred when an attempt was made to carry out the reaction HC C. CH2C1 + 2NH3 = NH4C1 +... 

M. Langsam, Fluorinated Polymeric Membranes for Gas Separation Processes, US Patent 4,657,564 (April, 1987) M. Langsam and C.L. Savoca, Polytrialkylgermyl-propyne Polymers and Membranes, US Patent 4,759,776 (July, 1988). 

Difiuoropropane (CH3CF2CH3).60 The vapor of 1 mole of propyne (b.p. —23.3°) is introduced into 4 moles of liquefied hydrogen fluoride in a metal container held at —23° by means of a carbon tetrachloride bath to hich enough solid carbon dioxide has been added to keep it mushy. Care is exercised to prevent the escape of any vapors. The reaction occurs at once. After completion of the addition, the reaction mixture is allowed to warm, and the vapors are passed through water and then condensed in a receiver cooled with solid carbon dioxide. The distillation of the condensate yields 54 g. (64%) of 2,2-difluoroethane, CH3CF2CH3, b.p. 0°. Lower reaction temperatures retard the addition, whereas higher temperatures favor polymerization. 

Many solvents form dangerous levels of peroxides during storage e.g., dipropyl ether, divinylacetylene, vinylidene chloride, potassium amide, sodium amide. Other compounds form peroxides in storage but concentration is required to reach dangerous levels e.g., diethyl ether, ethyl vinyl ether, tetrahydrofuran, p-dioxane, l,l-diethox) eth-ane, ethylene glycol dimethyl ether, propyne, butadiene, dicyclopentadiene, cyclohexene, tetrahydronaphthalenes, deca-hydrona-phthalenes. Some monomeric materials can form peroxides that catalyze hazardous polymerization reactions e.g., acr) lic acid, acr)Ionitrile, butadiene, 2-chlorobutadiene, chlorotrifluoroethylene, methyl methacrylate, styrene, tetrafluoroethylene,... 

Phenyl-1-alkynes (1-phenyl-l-propyne, -1-butyne, and -1-nonyne) polymerize in high yields in the presence of WClg—Pl Sn 30,32). The Mw s of the polymers, however, are not very high (5x 103-5x 104). MoCls—Ph4Sn is virtually inactive toward these acetylenes. 

Several disubstituted acetylenes containing other heteroatoms have been found to polymerize Derivatives of propiolic acid (PhC = CC02H, H02CC=CC02H) can be polymerized by MoCls— cocatalyst40). The polymerization of l-(ferrocenyl-l-propyne) is effected by WCl —Ph Sn 49). The MW s of these polymers, however, are not very high. 

Unlike the case of 1-phenyl-1-propyne, no polymer degradation occurs in the polymerization of 1-phenyl-1-butyne and higher 1-pheny 1-1-alkynes by NbCl or... 

Fig. 1. Time dependences of monomer conversion and polymer MW in the polymerization of 1-phenyl-l-propyne by TaCls-based catalysts in toluene, 80 °C, [Ml, = 1.0 M, [Cat] = 20 mM 57)...

As shown in Fig. 2, the polymerization of l-(trimethylsilyl)-l-propyne by TaCl5 is accelerated, and the MW of polymer is increased by use of Ph3Bi as cocatalyst61). To our knowledge, the Mw of 4 x 106 for poly[l-(trimethylsilyl)-l-propyne] obtained with TaCl5—Ph3Bi is the highest of those of any polyacetylenes reported to date. 

Polymerization of several homologs of l-(trimethylsilyl)-l-propyne has been examined. MeC=CSiMe2-w-C6Hl3, MeC sCSiMe2Ph, and MeC=CSiEt3 polymerize with TaCls-based catalysts 62) the Mw of the polymers ranges from 5 x 105 to 15 x 105... 

A catalyst solution is prepared by mixing TaCl5 (0.20 mmol, 72 mg) and -Bu4Sn (0.20 mmol, 69 mg) in toluene (5.0 ml), and aged by keeping at 80 °C for 15 min. To this solution is added a mixture of 1-phenyl-l-propyne (10 mmol, 1.2 g, 1.3 ml) and toluene (3.7 ml) at 80 °C. After 24 h, polymerization is stopped. The polymer is separated by precipitation into a large amount of acetone instead of methanol, because the cyclotrimers (by-products) dissolve in acetone, but not in methanol. Polymer yield 76%, Mw 1.5 x 106. 

Monocyclic, bicyclic and polymeric tetraaza(14)annulene ligands and their metal chelates (113)-(117) were prepared firom propynal and amines (Eq. 60) ... 

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