1-chloro-1-octyne

A molybdenum oxychloride-based catalyst system, MoOCl4- -Bu4Sn-EtOH, is more active than Mods ones. " In the polymerization of 1-chloro-l-octyne by the oxychloride-based catalyst, propagation rate is improved to be faster and MWD of the formed polymer is smaller. This ternary catalyst also induces living polymerization of... 

Chloro-l-alkynes (e.g., CICsCR R = n-Bu, n-C6H13, n-CgH17) polymerize with Mo catalysts in high yields. These monomers do not polymerize at all with W catalysts. As an example, Table 12 includes some results on the polymerization of 1-chloro-l-octyne 45). Both MoCls—cocatalyst and Mo(CO)6—CCI4—hv give polymers with Mw of 5 x 103-1 x 10 , while MoCls alone is less efficient. 

For the polymerization of disubstituted acetylenes, M0CI5 and WCl6 alone are inactive, and it is necessary to use the catalyst/cocatalyst mixtures (16), which are active for sterically less crowded monomers (e.g., 2-octyne and 1-chloro-l-octyne). In contrast, NbCls and TaCls by themselves polymerize disubstituted acetylenes with bulky substituents such as 1-(trimethylsilyl)-l-propyne. Diphenylacetylene and its derivatives, however, are polymerizable only with the TaCls-cocatalyst systems. The Nb and Ta catalysts selectively afford cyclotrimers from most monosubstituted acetylenes. 

FIGURE 2. Polymerization of 1-chloro-l-octyne by MoOCU-based catalysts (in toluene, 30 °C, 5 min each, [M]o = [M]added = 0.10 M, [Cat] = 20mM)... 

Many monomers with simple structures, including phenylacetylene, t-butyl-acetylene, 1-phenyl-1-propyne, 2-octyne, and 1-trimethylsilyl-l-propyne, are commercially available. These monomers are usually purified by distillation in the presence of suitable drying agents prior to use. On the other hand, monomers that are more complex, such as ort/zo-substituted phenylacetylenes, A-pro-pargylcarbamates, ring-substituted diphenylacetylenes, and 1-chloro-l-alkynes, must be synthesized. Derivatization of simple alkynes rather than formation of the acetylenic moiety, is frequently applied to synthesize such monomers. These are then purified by vacuum distillation or column chromatography. 

Example 24 Polymerization of 1-Chloro-l-octyne with a MoCls-Based Catalyst... 

The monomer solution is prepared by adding 1-chloro-l-octyne (6.0 mmol, 0.87 g, 0.95 mL), dodecane (0.35 mL as internal standard of GC), and toluene... 

Chlorine substitution in 1-hexyne reduces the C-l-C-2 C NMR shift difference from 15.75 in the parent to 12.51 ppm. This reveals that the effect of chlorine on 1-hexyne makes C-1 more positive and C-2 more negative. This effect of chlorine on the alkynes agrees with the -i-M effect analyzed in alkenes. An identical situation is observed in 1-chloro-l-octyne and in chlorophenylacetylene. 

The general formula of metal halide-based living polymerization catalysts is expressed as MO,jCl ,-co-catalyst-ROH (M = Mo or W, = 0 or 1, m = 5 or 4). The most important feature of these catalysts is ease of preparation, but their initiation efficiency is low. A typical living polymerization by metal halide-based catalysts has been achieved with 1-chloro-l-octyne as monomer and using MoOCl -w-Bu Sn-EtOH (1 in Table 15.2) as catalyst [41]. Specifically, poly(l-chloro-l-octyne) with a narrow MWD < 1.2) is obtained, and the... 

The azide-alkyne click reactions are useful to attach a number of polar FGs including various azobenzene moieties to the pendants of poly(l-phenyl-5-chloro-l-pentyne), (Eq. (7)) [90]. Nucleophilic substitutions of the same starting polymer result in the formation of an imidazole-functionalized, disubstituted acetylene polymer, (Eq. (8)) [91]. The degree of incorporation of the imidazole moiety is about 65%, and the product polymer exhibits good solubility in ethanol. Hydrolysis reaction of poly[l-(/w-methoxycarbonylphenyl)-l-octyne] yields a carboxy-functionalized disubstituted acetylene polymer poly[l-(/w-carboxyphenyl)-l-octyne], (Eq. 9) [92]. Hydrazine-catalyzed deprotection of poly[l-phenyl-ll-Af-benzimide-l-undecyne] affords the corresponding polyamine, which can be further ionized with hydrobromic acid to give a polyelectrolyte ammonium salt, (Eq. (10)) [93]. 

Chloro-l-octyne refluxed 48 hrs. with NaCN and Nal in 1 4 aq. ethanol, then KOH and water added, and refluxing resumed for a similar period 8-nony-noic acid. Y 98%. F. e. s. F. D. Gunstone and P. J. Sykes, Soc. 1962, 3055. 

Chloro-7-methyl-2-octyne 4-tert-Butyl-2-phenyloctane... 

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