Polymerization of allyl esters of unsaturated acids. I. Cyclopolymerization of methyl allyl maleate

Radical polymerization of methyl allyl maleate is kinetically discussed in terms of cyclopolymerization using 2,2′-azobisisobutyronitrile (AIBN) as an initiator and benzene as a solvent at 60°C. The ratios of the rate constants of the unimolecular cyclization reaction to those of the bimolecular propagation reaction of the uncyclized allyl and vinyl radicals, K_A and K_V, are estimated to be 9.7 and 1.35 mole/liter by fitting the kinetic equations obtained here to the dependence of the degree of cyclization on monomer concentration, respectively; the large difference between K_A and K_V is also discussed in detail. On the basis of these results the formation mode and the sequence distribution of the structural units of the polymer produced are discussed in detail; thus, for the polymer obtained in the bulk polymerization, about 90% of the cyclic structures can be formed via the intramolecular attack of uncyclized allyl radical on maleic double bond and the probability of succession of the cyclic structural units in diad sequence is exemplified as 0.27.     

Polymerization of allyl esters of unsaturated acids. VII. Copolymerization of methyl allyl maleate and fumarate with styrene

Radical copolymerizations of methyl allyl maleate (MAM) and methyl allyl fumarate (MAF) with styrene (St) are carried out in bulk using AIBN as an initiator at 60°C, and their copolymerization behaviors are compared in detail. The different rate features are observed with each other; thus in the MAF-St copolymerization the rate was quite enhanced and, also, the maximum rate was found at the molar ratio of 1:1 in the monomer feed, whereas no maximum phenomenon of the rate was apparent for the MAM—St copolymerization. The copolymerizability of MAF with St was quite high, whereas that of MAM was very poor. The cyclization of MAM or MAF was hindered by the highly reactive St monomer. These results are discussed in terms of the formation of the charge—transfer complex between MAF and St and, furthermore, the cyclocopolymerization kinetics involving the 17 elementary reactions as the propagation reactions.     

Polymerization of allyl esters of unsaturated acids. IV. Cyclopolymerization of diallyl maleate

Radical polymerization of diallyl maleate is kinetically discussed in terms of cyclopolymerization using 2,2′-azobisisobutyronitrile as an initiator and benzene as a solvent at 60°C. Thus, the kinetic equations involving bicyclo-intramolecular cyclization are derived by assuming steady-state conditions for the different types of radicals, and various parameters involved in the equations are then estimated approximately from an extension of the corresponding model experimental results. The validity of these treatments is confirmed from the comparison with the experimental data including the relationships between the contents of the unreacted allylic and maleic double bonds and the monomer concentrations. In addition, the sequence distribution of the structural units of the polymer produced is discussed; for example, the content of the bicyclic structural units is estimated to be 47.2% at a 10% dilution of the pure monomer.     

Polymerization of allyl esters of unsaturated acids. IX. Controlled ring closure in the radical cyclopolymerization of allyl methacrylate

Radical cyclopolymerization of allyl methacrylate (AMA) was investigated in detail, especially under the specified conditions; that is, above the ceiling temperature for a head-to-tail propagation (ΔG_ht ≥ 0) in the polymerization of methacrylate. Thus the structure of the polymer obtained was examined by ¹H- and ¹³C-NMR and infrared (IR) spectroscopy; no existence of unreacted pendant methacrylyl groups was observed, which suggests that, as a cyclopolymerization mechanism of AMA, intermolecular propagation of growing radicals, followed by intramolecular cyclization or intermolecular propagation of the resulting uncyclized methacrylyl radical, occurs exclusively with methacrylyl group. Temperature dependency of cyclization constant K_c was unusual; K_c increased rapidly at elevated temperatures and no linear relationship of ln K_c vs. 1/T was observed. Five-membered ring formation was favored at an elevated temperature and diluted monomer concentration. These results are discussed thermodynamically in terms of controlled ring closure in cyclopolymerization.     

Copolymerization of allyl esters of some fatty acids

Attempts have been made unsuccessfully to homopolymerize a number of allyl esters of substituted fatty acids by radical initiation in emulsion systems. Copolymerizations of these allyl esters with styrene, methyl methacrylate, and vinyl chloride have been investigated. Of these comonomers, styrene and methyl methacrylate do not copolymerize well with the allyl esters, whereas vinyl chloride does. Reactivity ratios for the radical copolymerization of allyl 11-iodoundecanoate, M₁, and vinyl chloride, M₂, determined at 60°C. in benzene, are r₁ = 0.42 and r₂ = 1.64. A copolymer of allyl 10, 11-dibromoundecanoate and vinyl chloride was fractionated and found to be fairly homogeneous.     

Oxidation of small unsaturated methyl and ethyl esters

The ignition delay times were measured behind reflected shock waves for temperatures from 1280 to 1930 K, pressures from of 7–9.65 atm, fuel concentrations of 0.4, 0.5, and 1%, and equivalence ratios equal to 0.25, 1.0, and 2.0 in the cases of four unsaturated esters: methyl crotonate, methyl acrylate, ethyl crotonate, and ethyl acrylate. Ignition delay times were measured using chemiluminescence emission from OH at 306 nm and piezoelectric pressure measurements made at the shock tube sidewall. No important difference of reactivity was observed between methyl and ethyl unsaturated esters, methyl and ethyl crotonate having the same reactivity as methyl butanoate. The reactivity of acrylates is greater than that of crotonates especially at the lowest investigated temperatures. Detailed mechanisms for the combustion of the four studied unsaturated esters have been automatically generated using the version of EXGAS software recently improved to take into account this class of oxygenated reactants. These mechanisms have been validated through satisfactory comparison of simulated and experimental results. The main reaction pathways have been derived from flow rate and sensitivity analyses. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 204–218, 2011     

Synthesis of unsaturated esters of pyridine-and quinolinecarboxylic acids

The vinyl esters of pyridine-2-and -4-carboxylic acids, the propargyl esters of pyridine-2-, -3-, and-4-carboxylic acids, the vinyl, allyl, and propargyl esters of quinoline-2-, -4-, and -8-carboxylic acids, and the allyl ester of 2-methylisonicotinic acid have been synthesized.     

Exotic amino acids. 4. Synthesis of methyl esters of some N-heteroamino-methylenemalonic acids

Isopropylidene N-hetarylaminomethylenemalonates, obtained from isopropylidene ethoxymethylenemalonate and 2-aminopyridine, 2-amino-5-methylpyridine, 2-aminopyrimidine, 7-amino-4-methylcoumarin, and 2-amino-3,5-diethoxycarbonyl-4-methylthiophene, undergo methanolysis at room temperature to give methyl esters of the corresponding N-hetarylaminomalonic acids. Isopropylidene N-hetarylaminomethylenenemalonate, containing a 2-aminothiazole group as a heterocyclic substituent, does not react under analogous conditions, but cyclizes upon heating at reflux to give 5-oxo-5H-thiazolo[3,2-a]pyrimidine-6-carboxylic acid. 4-Oxo-9-R-4H-pyridino[1,2-a]pyrimidines are obtained upon the sublimation of isopropylidene N-pyridyl- and N-5-methylpyridylaminomethylenemalonates.Communication 3, see ref. [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 857–860, June, 2000.     

Proton-acceptor capacities of allyl esters of furan-2-carboxylic acids

The basicities of 5-substituted allyl 2-furoates with respect to phenol and pentachlorophenol were investigated by IR spectroscopic methods. Measurements of the _OH values of phenols were made in CCl₄, and C₂Cl₄. The energy of the intermolecular H bond is 13–16 kJ/mole. The vinyl group of the allyl grouping in the allyl furoates retains its electron-acceptor character.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 598–600, May, 1978.     

Polymerization of coordinated monomers. V. Polymerization of methyl methacrylate–Lewis acid complexes

The polymerization of the complex of methyl methacrylate with stannic chloride, aluminum trichloride, or boron trifluoride was carried out in toluene solution at several temperatures in the range of 60° to ?78°C by initiation of α,α′-azobisisobutyronicrile or by irradiation with ultraviolet rays. The tacticities of the resulting polymers were determined by NMR spectroscopy. Both the 1:1 and the 2:1 methyl methacrylate–SnCl₄ complexes gave polymers with similar tacticities at the polymerization temperatures above ?60°C. With decreasing temperature below ?60°C, the isotacticity was more favored for the 2:1 complex, whereas the tacticities did not change for the 1:1 complex. On the ESR spectroscopy of the polymerization solution under the irradiation of ultraviolet rays at ?120°C, the 1:1 SnCl₄ complex gave a quintet, while the 2:1 SnCl₄ complex gave both a quintet and a sextet. The sextet became weaker with increasing temperature and disappeared at ?60°C. This behavior of the sextet corresponds to the change of the tacticities of polymer for the 2:1 SnCl₄ complex. An intra–intercomplex addition was suggested for the polymerization of the 2:1 complex, which took a cis-configuration on the basis of its infrared spectra. The sextet can be ascribed to the radical formed by the intracomplex addition reaction, while the quintet can correspond to that formed by the intercomplex addition reaction. The proportion of the intracomplex reaction was estimated to be about 0.25 at ?75°C, and the calculated value of the probability of isotactic diad addition of the intracomplex reaction was found to be almost unity.     

Synthesis of unsaturated esters of m- and p-carboranedicarboxylic acids

Conclusions Some unsaturated diesters of the m- and p-carboranedicarboxylic acids, which can be used in polymerization and copolymerization reactions, were synthesized and characterized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, p. 1904, August, 1982.     

Cyclopolymerization. VI. Polymerization mechanism of N-methyl-N-allylmethacrylamide at lower temperature

Mechanistic investigations on the polymerization of N-methyl-N-allylmethacrylamide (MAMA) at lower temperature were carried out based upon the ESR studies of MAMA and its monofunctional counterparts irradiated with ⁶⁰Co γ rays. Cyclopolymerizability of MAMA was also studied in connection with the hindered rotation about its amide C? N bond. The propagating radical observed is only related to the methacryl group but not to the allyl group both in MAMA and its monofunctional counterparts. Polymerization at ?78°C yielded a polymer with a lower degree of cyclization(88.8%) as compared with that of polymers formed at higher temperatures (93.5% above 0°C). A structural study revealed that the increment of the unsaturation in the poly-MAMA obtained at ?78°C is due to the allyl group and the content of pendant methacryl group is almost unchanged over the temperature range from ?78 to 120°C. These results led to the conclusion that the polymerization of MAMA at ?78°C proceeds mainly through the methacryl group, the rate-determining step is the cyclization reaction, and, in addition, cyclization reaction scarcely occurs when it polymerizes through the allyl group. Since MAMA is frozen into a glassy state, the effect of glass transition temperature (T_g) has been studied and it was suggested that the polymerization of MAMA proceeds only above T_g.     

Synthesis of unsaturated esters of pyridine- and quinolinedicarboxylic acids

The divinyl, diallyl, and dipropargyl esters of pyridine-2,4-, pyridine-2,6-, and quinoline-2,4-dicarboxylic acids and the divinyl and dipropargyl esters of pyridine-2,5-dicarboxylic acid have been synthesized.