Copolymerization of divinyl monomers with maleic and fumaric acid derivatives

The process of formation of reticular copolymer molecular structures produced in free radical copolymerization of divinyl monomers (divinyl ethers of diethylene glycol and hydroquinone, divinyl sulfide, p-divinylbenzene, etc.) with maleic and fumaric acid derivatives is studied. The basic factor that determines the features of molecular and network structures of copolymers is reactivity of the divinyl monomer in copolymerization with monovinyl monomer. The network of copolymers of maleic anhydride with the divinyl ether of hydroquinone is formed out of oligomer microgels. Divinyl sulfide in copolymerization with maleic acid is disposed to cyclocopolymerization; also crosslinking reactions occur. Formation of a network structure of copolymers of divinylbenzene with maleic and fumaric acid derivatives is shown to proceed via an alternating copolymerization mechanism. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36 : 371–378, 1998     

Cationic ring-opening transfer polymerization of spiro ortho esters initiated by carbon black

The ring-opening transfer polymerization of spiro ortho esters (SOE) initiated by carbon black was investigated. In the absence of carbon black, no polymerization occurred at all. In the presence of channel black containing carboxyl group, the ring-opening transfer polymerization of SOE was initiated at 50-70°C. to give polyether ester, namely alternating copolymer of epoxide and lactone. The rate of polymerization of 1,4,6-trioxaspiro[4.4]nonane and 1,4,6-trioxaspiro[4.5]decane was considerably small compared with that of 1,4,6-trioxaspiro[4.6]undecane. The activation energy of the polymerization of 2-chloromethyl-1,4,6-trioxaspiro[4.6]undecane was estimated to be 6.0 kcal/mol. The initiating activity of carbon black increased with an increase in carboxyl group content of carbon black. Furnace black that contained no carboxyl group was unable to initiate the polymerization. Furthermore, the carbon black lost the initiating ability of the polymerization upon the blocking of carboxyl group on the surface by the treatment with potassium hydroxide or diazomethane. Based on these results, it was concluded that carboxyl group on carbon black plays an important role in the initiation. During the polymerization, a part of the polymer formed was grafted onto carbon black: the grafting ratio was 10–30%. The mechanisms of initiation and grafting were discussed.     

Copolymerization of furan with maleic anhydride initiated by thioglycolic acid

Copolymerization of furan (F) with maleic anhydride (MAH) initiated by thioglycolic acid (TGA) was studied in various solvents and temperatures in the presence of atmospheric oxygen. Copolymer between F and MAH was readily obtained by using thiol compounds as initiators. The atmospheric oxygen catalyses the copolymerization reaction. The rate of copolymerization is proportional to the concentration [TGA]^0.55 at low concentrations (< 1.0 mol/L), at higher concentrations rates decrease gradually. The copolymerization rate increases with increase in copolymerization temperature and varies with the total monomer concentration as ([F] + [MAH])^1.9. The overall energy of activation as calculated from the Arrhenius plot has been found to be 6.4 Kcal/mol within the temperature range of 25–50°C.     

Copolymerization of acrylic acid with new acrylamide derivatives

Radical copolymerization of acrylic acid with acrylamide derivatives was studied. The cooplymerization constants were determined, and their dependence on the structure of the substituent in the acrylamide molecule and on the molecular weight of the polymers prepared was examined.     

Copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride and maleic acid

The free-radical copolymerization of 1,1,3,3-tetraethyl-2,2-diallylguanidinium chloride and maleic acid in bulk and organic solvents forms copolymers with a high tendency of monomer units toward alternation. It is shown that 1,1,3,3-tetraethyl-2,2-diallylguanidinium chloride undergoes copolymerization with maleic acid to give rise to pyrrolidinium structures in the cyclolinear polymer chain.     

Copolymerization of styrene with acrylonitrile and maleic anhydride

The complex formation constants for styrene (donor)-acrylonitrile (acceptor) and styrene-maleic anhydride (acceptor) systems are found to be 0.19 ± 0.01 and 0.28 ± 0.01 l/mol (¹H NMR, CCl₄, 298 K); the same values are characteristic for three-component systems of these monomers. The calculated ΔH ₀ values (the AM1 method) for styrene-acrylonitrile (C₁) and styrene-maleic anhydride (C₂) complexes comprise ?1.24 and ?2.30 kJ/mol. Changes in charges on double bonds of complex-bonded molecules are in the range from 0.001 to 0.006 au. These values are typical of π-π complexes. By analyzing the composition and rate of bulk copolymerization (333 K, 0.03 mol/l AIBN), we have shown that two complexes are involved in chain propagation: r ₁ = $ k_{2C_1 } /k_{2C_2 } $ = 0.26 ± 0.015 and r ₂ = $ k_{3C_2 } /k_{3C_1 } $ = 4.17 ± 0.143.     

Synthesis and thermal self-crosslinking reaction of polymer containing spiro ortho ester and carboxylic acid

Polymers with both pendant spiro ortho ester and carboxylic acid moieties were synthesized by partial esterification of poly(methacrylic acid), poly(methacrylic acid-co-methyl methacrylate), or poly(methacrylic acid-co-styrene) with halomethylated spiro ortho esters in the presence of 1,8-diazabicyclo[5,4,0]undecene-7 in dimethyl sulfoxide. The extent of esterification increased with increasing reaction temperature. The reaction of polymeric carboxylic acids with chloromethylated spiro ortho esters proceeded to 80% of conversion at 100°C for 120 h. In contrast, the degree of esterification with bromomethylated spiro ortho ester reached 80% at 60°C within 24 h. Thermo-crosslinking of polymers having pendant spiro ortho ester moiety and carboxylic acid could be effected in films. The rate of spiro ortho ester ring-opening increased with increasing reaction temperature and with increasing content of carboxylic acid groups in the polymer. Further, the rates of gel production were also measured. The polymer containing an equimolar mixture of spiro ortho ester moieties and carboxylic acids exhibited the highest reactivity. In addition, it was found that thermal crosslinking reaction of the polymer occurred with minimum volume shrinkage.     

Michael reactions of unsubstituted aromatic chiral imines with substituted unsaturated acid esters

The Michael reaction of chiral imines 1–3, derived from aromatic ketones’ with substituted electrophilic olefins generated asymmetric tertiary carbon centers. Nevertheless, asymmetric inductions were weaker than those usually observed with cycloalkanone imines.     

Gas chromatography of tricyclic spiro esters

Summary The separation of some tricyclic spiro esters on fused-silica capillary columns coated with dimethylsiloxane, cyanopropyl methyl siloxane and poly(ethylene glycol) stationary phases was investigated. Retention indices were determined at two temperatures to interpret their chromatographic behaviour. The repeatability of the measurements was 0.2, 0.3 and 0.5 index units. The influence of the polarity of the stationary phases on the chromatographic retention of these tricyclic spiro esters is discussed.     

New synthesis of ortho esters of sugars

Summary A new synthesis of ortho esters of sugars has been proposed, starting with 1,2-cis-halogenoses in ethyl acetate medium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12 p. 2214–2216, December, 1964     

Copolymerization of styrene with maleic anhydride initiated by thiol compounds

Copolymerization of styrene (ST) with maleic anhydride (MAH) initiated by thiol compound was investigated under various conditions. The kinetics of copolymerization of ST with MAH initiated by p-toluenethiol (pTT) was studied in dioxane in the temperature range of 25–60°C, and the rates (R_p) of copolymerization and activation energy were determined. R_p was found to depend on [pTT],^0.6 ([ST] + [MAH])^2.7. The overall energy of activation was 10.8 kcal/mol in the temperature range of 25–60°C. A mechanism involving the formation of a complex between MAH and pTT the decomposition of which yields the initial radical is suggested.