Polyrecombination Reaction Research Articles

First polyrecombination reaction via atom transfer radical coupling (ATRC), a new way for the synthesis of poly(p-xylylene)

p-Dibromo xylene, a typical atom transfer radical polymerization (ATRP) bifunctional initiator, was polymerized in atom transfer radical coupling (ATRC) conditions, yielding poly(p-xylylene). In order to confirm the success of the reaction by 1H-NMR spectroscopy and GPC, a more soluble product, poly(methyl methacrylate-b-p-phenylene-ethylene), was also synthesized by adding 5% poly(methyl methacrylate) with an activated bromine atom at the chain end obtained by ATRP to the polymerization feed. The 1H-NMR spectrum shows the presence of poly(p-xylylene) component in the co-polymer. The GPC measurement also shows an increase of molecular weight together with a decrease of polydispersity, proving the formation of the co-polymer. The method described here opens a new pathway for synthesis of polymers from various classes by using appropriate ATRP bifunctional initiators as monomer, in ATRC or even ATRP conditions.

Metallocene polymers : XXVIII. trans-1,2-Diferrocenylethene as a by-product in the ferrocene recombination reaction

A compound obtained as a low-yield by-product in the polyrecombination reaction of ferrocene, to which initially a terferrocenyl structure had been ascribed on a tentative basis, has been identified as trans-1,2-diferrocenylethene. This structural assignment is supported by IR, PMR and mass spectral evidence, and firmly established by comparison with authentic samples.

Metallocene Polymers : XXVI. Isomeric terferrocenyls in the polyrecombination reaction of ferrocene

A re-examination of the oligonuclear by-products arising in the previously reported polyrecombination reaction of ferrocene in the presence of tert-butyl peroxide has revealed the presence of an additional trinuclear compound, m.p. 198–200°, to which the structure of 1,2-diferrocenylferrocene (1,2-terferrocenyl) is ascribed on the basis of spectroscopic and other evidence. The compound is found to be identical with an authentic sample synthesised by other workers. Separation from other oligonuclear ferrocenes is accomplished by column chromatography. This result, coupled with the firm identification of the remaining two possible terferrocenyl isomers of the previous study as 1,3-terferrocenyl and 1,1′-terferrocenyl, necessitates a reassignment of the compound, m.p. 260–265°, which had tentatively been identified in that study as a terferrocenyl.

Synthesis of polymers from aromatic amines by the polyrecombination reaction

1. As a result of the poly recombination reaction with the aromatic diamines p-phenylenediamine and benzidine polymers of the polyazobenzene type are formed which have high softening points and give narrow ESR signals. 2. A structure is proposed for these polymers, and a possible scheme for their formation is discussed.

Synthesis of polymers from phenols, their ethers, and their esters by the polyrecombination reaction

1. By the polyrecombination of phenol, p-crosol, hydroquinone, p-dimethoxybenzene, and hydroquinone diacetate new types of polymers were obtained, and their properties were investigated. 2. A probable scheme for the formation of these polymers is proposed; in the case of phenols with free hydroxy groups this takes account of the preliminary “cross” recombination of phenoxy radicals with active free radicals. 3. The hydroquinone polymer, whose chain consists of alternating hydroquinone and benzoquinone rings, has high thermal stability and an intense ESR signal.

Synthesis of polymers by polyrecombination of the nitrile of aromatic and aliphatic acids

TEE formation of polymers with a system of C----N conjugate bonds has already been established in our studies [1, 2] of the decomposition of tert-butyl peroxide in the nitriles of fatty and aromatic acids containing methyl and methylene groups. Now we felt it would be interesting to find out how a eyano derivative containing no mobile hydrogen atoms in the methyl, methylene or methide groups would behave under polyrecombination reaction conditions. We also wished to synthesize copolymers of aliphatic acid nitriles having, besides the increased thermal stability due to the system of conjugate bonds, also good solubility in .organic solvents and softening point below their decomposition temperature. To solve the first problem tert-butyl peroxide was treated in benzonitrile, which is a compound containing no mobile hydrogen atoms. Nevertheless, the polyrecombination reaction produced a polymer besides a large amount of unreacted original material. In his study of the methylation of benzene and its derivatives [3, 4], Szwarc found that the benzene derivatives with strong electron acceptor substituents have a strong tendency to methylation. Accordingly, it has been suggested that %he benzonitrile is first methylated and the polymer is formed from the corresponding tolunitriles. This proposition is confirmed, in particular, by the low Cert-butyl alcohol: acetone ratio (0.11 in the early stage of the reaction), which shows thaf a large part of the butoxyl radicals break down according to the reaction (CH3)3C0--> CI-I~ + CHaCOCH a. IR spectroscopy and elementary analysis show that the methyl radicals formed enter the ring with formation of tolunitrile. The latter in its turn undergoes (Iehydrogenation, but is not yet able to react with the methyl group [5]. The increased reactivity of the solvents reduces the degradation of the butoxyl radicals and increases the alcohol: acetone ratio to 0.37 (a consumption of 2 or 33aore moles peroxide per mole benzonitrile).

A study of the possibility of obtaining high-molecular-weight compounds from diphenylsilane under the conditions of the polyrecombination reaction

A study of the possibility of obtaining high-molecular-weight compounds from diphenylsilane under the conditions of the polyrecombination reaction

Possibility of synthesizing high molecular compounds from diphenylgermanium under the conditions of the polyrecombination reaction

Possibility of synthesizing high molecular compounds from diphenylgermanium under the conditions of the polyrecombination reaction

Synthesis of polymers from diphenylmethane derivatives with the aid of the polyrecombination reaction

1. In the polyrecombination of diphenylmethane derivatives polymers and oligomers are formed. 2. Probable structures, which are in accordance with the elementary analysis and the infrared spectra, are proposed for the polymers obtained. 3. It is shown that the tendency for polymer formation is less for diphenylmethane derivatives containing electron-accepting substituents than for diphenylmethane itself. It is suggested that the cause of this difference lies in the electron density of the C-H bond of the methylene group of such a substituted diphenylmethane. 4. Four polymers and six pure compounds were prepared and characterized.

Reaction of aliphatic and aromatic nitriles with t-butyl peroxide

1. In the polyrecombination reaction certain aliphatic and aromatic nitriles (phenylacetonitrile, α-cyano-p-tolunitrile, and p-tolunitrile) give oligomers and polymers containing a system of conjugated C=N bonds and giving an ESR signal. 2. Probable structures of the polymers and reaction schemes for their formation are proposed which are in accord with their elementary analyses and their infrared and ESR spectra. 3. In the case of α-cyano-p-tolunitrile the effect of steric hindrance on the tendency to form polymers is shown. 4. It was shown that the presence of one or two electron-accepting nitrile groups has an unfavorable influence on the mobility of the hydrogen atoms of the methylene group of the starting compound and on the tendency of such compounds to form polymers.

Preparation of a polymer from benzyldiphenylphosphine oxide by the polyrecombination reaction

1. It was shown that organophosphorus polymers can be prepared with the aid of the polyrecombination reaction. 2. Poly[benzyldiphenylphosphine oxide] was prepared, and its properties were studied. 3. The presence of phosphorus in the monomer molecule has a passivating effect on the mobility of the hydrogen of the methylene group. 4. Some regularities in the polyrecombination process were examined.

Synthesis of polymers from aliphatic nitriles

1. As a result of the polyrecombination reaction some aliphatic nitriles (methyl cyanoacetate, malononitrile, adiponitrile) give polymers containing systems of conjugated bonds. In some cases the polymers have high softening points. 2. A possible scheme for the formation of these polymers is proposed that is in accord with the results of elementary analysis and of infrared and e.s.r. spectroscopy. 3. The electrophysical and thermomechanical properties of the polymers obtained were investigated.

Preparation of new types of linear polymers by the polyrecombination reaction

AbstractIn an extension of previously reported studies of the use of the polyrecombination reaction to synthesize high molecular weight compounds, it has been shown for the first time that this method yields linear polymers without any significant formation of threedimensional structures. Such polymers may be synthesized from compounds containing a methylene group in the α‐position to the benzene ring, carboxyalkyl or carboxyphenyl groups. On treatment of diphenylmethane with tert‐butyl peroxide, a linear polymer of molecular weight 10,000‐900,000 (depending on the quantity of peroxide used) was obtained. Linear polymers in the form of benzene‐soluble powders were also obtained from benzyl benzoate (molecular weight 400,000), methyl phenylacetate, etc. The composition and structure of the polymers obtained were confirmed by chemical analysis and infrared spectroscopy. The relation between the molecular weight of the polymer and the amount of peroxide consumed in the reaction was also established. If groups capable of serving as branching centers in the polymer (e.g., methyl groups in ditolylmethane) are present in the starting compounds, three‐dimensional products are formed along with the linear polymers.

Preparation of high molecular compounds by the polyrecombination reaction

1. (1) It is shown that linear high molecular products can be synthesised from saturated compounds by a new method—the polyrecombination reaction based on the recombination reactions of solvent free radicals. 2. (2) The reaction was investigated with p-di isopropylbenzene as the example (linear polymers with molecular weights of ∼ 10,000 were obtained) and extended to a series of other saturated compounds possessing reactive hydrogen atoms such as p-xylene, di isopropylketone, di isopropylferrocene, and also diphenyl and p-dichlorobenzene. 3. (3) In the polyrecombination reaction chain growth is accomplished by frequently repeated acts of formation and recombination of radicals, i.e. it is stepwise in character. In this way, and the isolation of low-molecular reaction products, it is similar to the polycondensation reaction. However, in distinction from the latter, the reverse process of chain destruction is apparently absent from the polyrecombination reaction. 4. (4) It is shown that it is possible to regulate the ratio of insoluble (three-dimensional) to soluble (linear) polymer in the reaction of p-di isopropylbenzene with tert-butyl peroxide by adding benzoic acid to the reaction mixture as modifier, and a possible mechanism for its effect is discussed.