Polyacetylene from acetylene

Even with improvement in properties of polyacetylenes prepared from acetylene, the materials remained intractable. To avoid this problem, soluble precursor polymer methods for the production of polyacetylene have been developed. The most highly studied system utilizing this method, the Durham technique, is shown in equation 2. 

GLASER - CHODKIEWCZ Acetylene Coupling Polyacetylenes from monoacetylenes in the presence of copper salts. 

Figure 13 shows the irreversible conversion of a nonconjugated poly (p-phenylene pentadienylene) to a lithiun-doped conjugated derivative which has a semiconducting level of conductivity (0.1 to 1.0 S/cm) (29). Obviously, the neutral conjugated derivative of poly (p-phenylene pentadienylene) can then be reversibly generated from the n-type doped material by electrochemical undoping or by p-type compensation. A very similar synthetic method for the conversion of poly(acetylene-co-1,3-butadiene) to polyacetylene has been reported (30), Figure 14. This synthesis of polyacetylene from a nonconjugated precursor polymer containing isolated CH2 units in an otherwise conjugated chain is to be contrasted with the early approach of Marvel et al (6) in which an all-sp3 carbon chain was employed.

Synthesis of polyacetylene from poly(acetylene-co-1,3-butadiene). 

A graduate student in Hideki Shirakawa s laboratory at the Tokyo Institute of Technology was trying to make a polymer called polyacetylene from ordinary acetylene welding gas. The polymer, a dark powder, had first been synthesized in 1955, but no one knew much about it. Instead of a dark powder, Shirakawa s student produced a lustrous, silvery film that looked like aluminum foil but stretched like Saran wrap. Looking back over his chemical recipe, the student saw his... 

Various vinyl polymers 1 are manufactured on a large scale, whereas practically no polyacetylenes 2 are produced by the industries. One of the reasons is that it was difficult to synthesize high polymers from acetylenes in good yields. However, the synthesis of high-molecular-weight polyacetylenes is currently becoming feasible. 

Twenty five years after the first report on catalytic polymerization of acetylene by Shirikawa, McDiarmid and Heeger [130], the Nobel prize has been awarded to these researchers for their contribution to the field of conducting polymers. Indeed, such polymers have promising applications such as low weight/high charge density batteries, polymer-modified electrodes, or capacitors to name only a few. Driven by these applications, different classes of polyacetylenes have been synthesized, starting from acetylene itself and from mono- or disubstituted acetylene derivatives. 

The second approach to a more tractable polyacetylene is to sidestep the compromises described above by developing multistep syntheses which proceed via a soluble precursor polymer [31, 48-50]. Although the final product is still insoluble, the solubility of the precursor allows both the determination of properties, such as molecular weight, as well as more facile manipulation of the polymer into a desired macroscopic shape. In addition, these routes also provide polyacetylene films that differ in microscopic morphology from those synthesized directly from acetylene. However, these advantages come with added complexity not only do these routes require a reaction, frequently carried out in the solid state, to go to completion, but there is also usually the need to remove an eliminated by-product from the solid product. 

Polyacetylene is made from acetylene in a reaction that looks simple but is actually tricky to do ... 

It is a gas, which is kept in cylinders and used for soldering iron. This shows that the flame arising from the burning of acetylene is very, very hot. From acetylene, we make the polymer polyacetylene (it is now used in batteries for electric cars). Acetylene is adso an example of molecules containing triple C C bonds, which, as a group, are called alkynes. 

In 1885 Bayer investigated a series of interesting but dangerous compounds, the polyacetylenes. From dibromosuccinic acid (I) he obtained acetylene... 

Many papers in the literature have followed the finding by Masuda and coworkers (9). This article covers the literature from the mid-1980s up to mid-2000. As a result of the rapid growth in the area, the chemistry of polymers from acetylene, 1,3-diacetylenes, and Q, < -diacetylenes are excluded (see Polyacetylene Diacetylene and Tbiacetylene Polymers). The first focus is on the polymerization reaction of substituted acetylenes with various transition metal catalysts. The synthesis of functionally designed polyacetylenes is also covered. Readers are encouraged to access other reviews and monographs on polyacetylene (10-14), on 1,3-diacetylenes (15-19), and on a,Previous review articles are also helpful to survey the chemistry of substituted polyacetylenes (10,13,22-29). 

Write three repeating units of the addition polymer that can be made from acetylene. This materiaL called polyacetylene, conducts electricity because of the alternating single-hond/ double-bond pattern in the main chain. 

Bentley, R.K., Jones, E.R.H. andThaHer, V. (1969b) Natural acetylenes. Part XXX. Polyacetylenes from Lactuca (lettuce) species of the Liguliflorae sub family of the Compositae. /. Chem. Soc. (C), 1096-1099. 

Anchel, M. Acetylenic compounds from fungi. J. Am. Chem. Soc. 74, 1588 (1952) Anchel, M. Identification of an antibiotic polyacetylene from Clitocyhe diatreta as a suberamic acid ene-diyne. J. Am. Chem. Soc. 75, 4621 (1953a). 

STEPHENS CASTRO Acetylene cycloptiane synthesis Polyacetylene cyclophane synthesis from an iodophenyl copper acetylide... 

The discovery of junipal focused the attention of Sorensen, who had been investigating the occurrence of polyacetylenes in Com-positae, on the possibility that these acetylenes were accompanied by thiophenes. From Coreopsis grandiflora Hogg ex sweet, 2-phenyl 5-(1-propynyl) thiophene (240) was isolated and its structure confirmed by synthesis of the tetrahydro compound, 2-phenyl-5-n-propyl-thiophene. From the root of tansy, the cis and trans isomers of methyl 5-(l-propynyl)-2-thienylacrylate (241) have been isolated. The total synthesis of trans (241) was achieved by reacting junipal with methylcarbethoxy triphenylphosphonium bromide (Wittig reaction) Several monosubstituted thiophenes, (242), (243), and... 

Naturally Occurring Acetylene Compounds. XX. A Preliminary Communication on Some Polyacetylenic Pigments from Compositae Plants. Acta Chem. Scand. 8, 1769 (1954). 

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). 

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