Condensation polymers acetylene

Acetylene is condensed with carbonyl compounds to give a wide variety of products, some of which are the substrates for the preparation of families of derivatives. The most commercially significant reaction is the condensation of acetylene with formaldehyde. The reaction does not proceed well with base catalysis which works well with other carbonyl compounds and it was discovered by Reppe (33) that acetylene under pressure (304 kPa (3 atm), or above) reacts smoothly with formaldehyde at 100°C in the presence of a copper acetyUde complex catalyst. The reaction can be controlled to give either propargyl alcohol or butynediol (see Acetylene-DERIVED chemicals). 2-Butyne-l,4-diol, its hydroxyethyl ethers, and propargyl alcohol are used as corrosion inhibitors. 2,3-Dibromo-2-butene-l,4-diol is used as a flame retardant in polyurethane and other polymer systems (see Bromine compounds Elame retardants). 

The synthesis of optically active polymers is an important area in macromolecular science, as they have a wide variety of potential applications, including the preparation of CSPs [31-37]. Many of the optically active polymers with or without binding to silica gel were used as CSPs and commercialized [38]. These synthetic polymers are classified into three groups according to the methods of polymerization (1) addition polymers, including vinyl, aldehyde, isocyanide, and acetylene polymers, (2) condensation polymers consisting of polyamides and polyurethanes, and (3) cross-linked gels (template polymerization). The art of the chiral resolution on these polymer-based CSPs is described herein. 

Ohmura, K. Kijima, M. Shirakawa, H. Synthesis of conducting polymers with conjugated carbon-carbon triple bonds by electrochemical condensation of acetylene derivatives catalyzed by copper complex. Synth. Metals 1997, 84, 417-418. 

This volume continues in the tradition of Volume I in presenting detailed laboratory instructions for the preparation of various types of polymers such as urea, melamine, benzoguanamine/aldehyde resins (amino resins-amino-plasts), phenol/aldehyde condensates, epoxy resins, silicone resins, alkyd resins, polyacetyls/polyvinyl acetals, polyvinyl ethers, polyvinyl pyrroli-dones, polyacrylic acids, and polyvinyl chloride. Polyvinyl acetate and related vinyl esters, allyl polymers, acetylene polymers, maleate and fumarate polymers, and several other addition-condensation polymer types will be covered at a later date in Volume III. 

Both this and previous studies demonstrate the existence of rather long chains of consecutive ion-molecule reactions in methane, ethylene, and acetylene, and thus they provide direct evidence for ionic mechanisms of condensation or polymerization in these gases. Polymers have been found in relatively high yields among the radiolysis products of these... 

Acetylene Condensation and Polymerization Products may be obtained by subjecting acetylene to the action of heat, light electrons, alpha-rays, elec discharge, etc with or without catalysts (Ref 1, i892-3ll One such products is cuprene(qv), which is a condensation product of acetylene and not a polymer as it is usually called. The real polymerization product of acetylene is... 

Hexafluoroacetone is a reactive electrophile. It reacts with activated aromatic compounds (e.g., phenol), and can be condensed with olefins, dienes, ketenes, and acetylenes. It forms adducts with many compounds containing active hydrogen (e.g., H.,0 or HCN). Reduction of HFA with NaBH or LiAlH affords the useful solvent hexafluoroisopropyl alcohol. The Industrial importance of HFA arises largely from its use 1n polymers and as an... 

Cyclotrimerization of polyfunctional aryl acetylenes offers a unique route to a class of highly aromatic polymers of potential value to the micro-electronics industry. These polymers have high thermal stability and improved melt planarization as well as decreased water absorption and dielectric constant, relative to polyimides. Copolymerization of two or more monomers is often necessary to achieve the proper combination of polymer properties. Use of this type of condensation polymerization reaction with monomers of different reactivity can lead to a heterogeneous polymer. Accordingly, the relative rates of cyclotrimerization of six para-substituted aryl acetylenes were determined. These relative rates were found to closely follow both the Hammett values and the spectroscopic constants A h and AfiCp for the para substituents. With this information, production of such heterogeneous materials can be either avoided or controlled. 

The poly(silylene-co-ethynylene)s, described in the literature, mainly contain SiPh- or SiMe-groups, rarely SiH- or SiVi-units. These polymers or oligomers are currently produced by the condensation of dihalosilanes with the di-Grignard reagent of acetylene [3, 4], dilithioacetylene [5-7] or disodiumacetylide [8]. 

The condensation of formaldehyde on acetylene requires an extremely active and highly selective catalyst system to prevent explosions due to the use of excessively high acetylene partial pressures and the undesirable formation of cuprene, a polymer of acetylene. The catalyst used today is copper acetylide, deposited on a magnesium silicate support containing bismuth. Operations are -conducted at low pressure (0.1.10 Pa -absolute) and at relatively moderateiemperature (95°C) in a continuously fed system. 

The synthesis of pentasubstituted pyrroles has been reported by Mjalli and Toyonaga [46] using a multicomponent condensation. The treatment of the intermediate 10 with neat acetic anhydride or isobutylchloroformate and tri-ethylamine in toluene, followed by the addition of a series of acetylenic esters, provided the polymer-bound pentasubstituted pyrroles 12 (Fig. 4). The reaction proceeded by in situ cyclization of the intermediate via [3+2]... 

Metal-containing polymers can be synthesized by the vapor deposition polymerization of various monomer systems including organometallic compounds and metal-monomer co-condensates. Such co-condensates are produced by simultaneous or layer-by-layer deposition of metal and monomer vapors on substrate plates at low temperatures (usually, 77 K). Polymerization can proceed in different ways. Some metal-monomer systems polymerize during cocondensation (Ge and Sn with acetylene [11], Mg with CN-substituted p-xylylene [12]), most probably due to heat released at condensation. In references 13-16, co-condensates of metals (Pd, Ag, Au, etc.) and vinyl monomers... 

The above-described two-step processes yield polymers that evolve volatiles upon further heating because the condensations continue. To overcome this drawback, prepolymers were developed thatundeigo addition-type reactions at fairly moderate time-temperature schedules. Such prepolymers are terminated by functional groups. The following is an example of one such material, an oligomer, polyquinoxaline-terminated by acetylene groups ... 

Ammonia Dibutyltin maleate Dibutyltin oxide Fluorosulfonic acid Phosphine Sodium ethylate Sodium hydride Tetrabutyl titanate Tetraisopropyl titanate p-Toluene sulfonic acid Zirconium butoxide catalyst, condensation reactions Dibutyltin diacetate Piperidine catalyst, conductive polymers Iron (III) toluenesulfonate catalyst, conversion of acetylene to acetaldehyde Mercury sulfate (ic) catalyst, copolymerization Di butyl ether catalyst, cracking Zeolite synthetic... 

When the acetylenic groups are in the para positions on the aromatic ring, condensation with a metal phosphine leads to a linear polymer as in (8.358), but if these groups are in the ortho position a cyclic tetrameric ring is produced as in (8.357) [33]. With three pendant acetylenic groups, dendritic-type structures can be obtained as in (8.356). 

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