Catalytic C-phenylation of methyl acrylate with triphenylantimony(v) dicarboxylates

Triphenylantimony dicarboxylates Ph₃Sb(OAc)₂ and Ph₃Sb(O₂CEt)₂ are efficient C-phenylating agents for methyl acrylate. In the presence of the Pd(OAc)₂, Li₂PdCl₄ or Pd₂(dba)₃(CHCl₃) catalysts in MeCN at 50 °C, methyl cinnamate forms in 70—150% yield with respect to Sb^V. Copper(ii) salts do not increase the reaction yield.     

The reaction of dihydridotetrakis(triphenylphosphane)ruthenium(II) with methyl acrylate. Crystal structure of bis(methylacrylate)bis(triphenylphosphane)(aqua)ruthenium(0)

The complex H₂Ru(PPh₃)₄ reacts with methyl acrylate to give bis(methylacrylate)bis(triphenylphosphane)ruthenium(0). Temperature-dependent NMR spectra show that the complex exists in two isomeric forms in solution. The major form (ca. 74%) has one methyl acrylate ligand η²-coordinated and the other η⁴ -coordinated as a 1-oxabutadiene ligand. This complex reacts with water to give the monoaqua adduct, the crystal structure of which is reported.     

Catalytic C-phenylation of methyl acrylate with tetraphenylantimony(v) halides and carboxylates

Catalytic C-phenylation of methyl acrylate to methyl cinnamate with the Ph₄SbX complexes (X = F, Cl, Br, OH, OAc, O₂CEt) in the presence of the palladium compounds PdCl₂, Pd(OAc)₂, Pd₂(dba)₃, Pd(Ph₃P)₂Cl₂, and Pd(dppf)Cl₂ (dba is dibenzylideneacetone and dppf is bis(diphenylphosphinoferrocene)) was studied in organic solvents (MeCN, THF, DMF, MeOH, and AcOH). The highest yield of methyl cinnamate (73% based on the starting organometallic compound) was obtained for the Ph₄SbCl—PdCl₂ (1 : 0.04) system in acetonitrile.     

Tail-to-tail dimerization of methyl acrylate in the presence of triphenylarsine ruthenium complexes

Catalytic dimerization of methyl acrylate by homogenous ruthenium catalysts was investigated. The effect of the addition of acidic additives, supporting ligands, polymerization inhibitor, and reaction conditions on the selectivity of dimerization was studied, and possible reaction mechanism was discussed. Conversion and selectivity were significantly affected by using triphenylarsine as supporting ligand. Under mild conditions, conversion up to 98% with good selectivity to tail-to-tail product was achieved.     

Synthesis and Characterization of the Polyacrylonitrile-block-poly（methyl acrylate） by RAFT Technique

Reversible addition-fragmentation chain transfer polymerization (RAFT) was firstly reported in 1998 by Rizzardo1. This technique provided the possibility to synthesize polymers with controlled molecular weight, narrow molecular weight distribution, and we…     

Dramatic acceleration of SET‐LRP of methyl acrylate during catalysis with activated Cu(0) wire

A simple method for the activation of the Cu(0) wire used as catalyst in single‐electron transfer living radical polymerization (SET‐LRP) is reported. The surface of Cu(0) stored in air is coated with a layer of Cu₂O. It is well established that Cu₂O is a less reactive catalyst for SET‐LRP than Cu(0). We report here the activation of the Cu(0) wire under nitrogen by the reduction of Cu₂O from its surface to Cu(0) by treatment with hydrazine hydrate. The kinetics of SET‐LRP of methyl acrylate (MA) catalyzed with activated Cu(0) wire in dimethyl sulfoxide (DMSO) at 25 °C demonstrated a dramatic acceleration of the polymerization and the absence of the induction period observed during SET‐LRP catalyzed with nonactivated Cu(0) in several laboratories. Exposure of the activated Cu(0) wire to air results in a lower apparent rate constant of propagation because of gradual oxidation of Cu(0) to Cu₂O. This dramatic acceleration of SET‐LRP is similar to that observed with commercial Cu(0) nanopowder except that the polymerization provides excellent molecular weight evolution, very narrow molecular weight distribution and high polymer chain‐end functionality. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Sequence Distribution of Poly(methyl acrylate) by Incremental Calculation

The carbonyl signal in the 100 MHz ¹³C NMR spectra of poly(methyl acrylate) (PMA) recorded in benzene-d₆ exhibits configurational sensitivity up to pentads, and the signal of backbone β-CH₂ carbons shows splitting up to configurational hexads with traces of octads. Assignment of the sequences to respective signals was confirmed by computer simulation of both carbonyl and methylene signals applying a method of incremental calculation of chemical shifts of individual sequences and second-order Markov statistics for sequence probabilities.     

聚丙烯酸甲酯载体对柱状假丝酵母脂肪酶固定化的研究（Ⅰ）

合成了一系列不同结构的聚丙烯酸甲酯，考察了它们的固定化酵母脂肪酶催化酯水解反应的效果，得到了载体孔结构对固定化效果影响的一些规律．研究了最佳吸附条件，比较ｐＨ和离子强度对酵母脂肪酶自由酶和固定化酶催化酯水解反应活力的影响．     

Synthesis of Poly(methyl acrylate) Grafted onto Silica Particles by Z-supported RAFT Polymerization

RAFT polymerization of methyl acrylate (MA) mediated by silica-supported 3-(methoxycarbonyl-phenyl-methylsulfanylthiocarbonylsulfanyl) propionic acid (Si- MPPA) and 3-(benzylsulfanylthiocarbonylsulfanyl) propionic acid (Si-BSPA) was investigated. The molecular weight and polydispersity of grafted polymeric chains and the grafted chain transfer agent (CTA) efficiency (G_e) were strongly dependent on the types and loading of Si-CTAs and free CTA used in solution. Under similar reaction conditions, the graft polymerization mediated by Si-MPPA was better controlled than that using Si-BSPA. The introduction of a free CTA in solution during Si-MPPA mediated polymerization could significantly decrease the polydispersity of free and grafted polymeric chains and enhance the grafted CTA efficiency, and longer polymeric chains could be grafted onto silica support when Si-MPPA with a higher CTA loading was used to mediate the polymerization. In all cases, the RAFT polymerization using 2-(2-cyanopropyl) dithiobenzoate (CPDB) as a free CTA could afford well-defined grafted PMA and significantly increased G_e value, while the polymerization rate was also decreased.     

Direct transesterification of poly(methyl acrylate) for functional polyacrylate syntheses

Post‐polymerization modification is an important synthetic method to produce macromolecules with various chemical and physical properties. With this technique, functional groups of polymer molecules within the same structural scaffold can be varied, and thus, accurate research on structure‐property relationships is possible. To add practicality, the direct post‐polymerization of commodity polymers has been pursued, but only limited success has been realized. In this report, a study on various transesterification methods for the synthesis of functional polyacrylates beginning with a poly(methyl acrylate) (PMA), one common acrylate polymer, is presented. The Zn‐based catalytic system, a combination of Zn₄(OCOCF₃)₆O and 4‐dimethylaminopyridine with instant methanol removal, exhibited the highest reactivity among many catalysts and conditions. Assorted alcohols were reacted with PMA to produce the corresponding polyacrylates. This method was successfully extended to post‐polymerization modification of a PMA‐containing block copolymer, PS‐b‐PMA and synthesis of acrylate copolymers with functional group density control. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2554–2560     

Microstructure of poly(methyl methacrylate-co-isopropyl acrylate) studied by 13C NMR

The distribution of configurational–compositional sequences of poly(methyl methacrylate-co-isopropyl acrylate) (PMMA/iPrA) has been determined from the carbonyl and β-CH₂ signals in the 100?MHz ¹³C NMR spectra of the copolymer. The carbonyl signal provided information on configurational–compositional sequences up to heptads, whereas β-CH₂ signals offered complementary information on even sequences up to hexads. The assignment of the sequences to the respective signals was based on a comparison with the spectra of respective homopolymers, that is, PMMA and PiPrA followed by a computer simulation applying an incremental calculation of chemical shifts of the individual sequences.     

Shock tube ignition delay time measurements for methyl propanoate and methyl acrylate: Influence of saturation on small methyl ester high-temperature reactivity

We report ignition delay time measurements for methyl propanoate (MP) and methyl acrylate (MA), carried out in a high-pressure shock tube. Experiments were performed behind reflected shock waves across a temperature range of 989-1 367 K, for fuel-air mixtures at equivalence ratios of ϕ = 0.5, 1.0, and 2.0, and nominal pressures of 1 and 4 MPa. Ignition delay times were found to decrease with increasing temperature, equivalence ratio, and pressure, and are well described with correlations involving Arrhenius temperature dependence and power-law dependence on equivalence ratio and pressure. Ignition delay times are compared with model predictions from literature kinetic models, with the models of Zhang et al (Energy & Fuels 2014; 28(11): 7194-7202) and Bennadji et al (International Journal of Chemical Kinetics 2011; 43(4): 204-218.) in good agreement with measured ignition delay times for MP and MA, respectively. Kinetic sensitivity analysis shows that the reactions most important for modeling ignition fall into two categories: initiation reactions (ie, decomposition and H-atom abstraction) and C₀-C₁ chemistry controlling the pool of small radicals. The unsaturated MA was observed to have lower reactivity than MP, due to its greater bond strengths for C─C and C─H bonds, resulting in slower rates for initiation reactions.     

Dephenylation of triphenylbismuth(v) and antimony(v) derivatives in a methyl acrylate—methanol system in the presence of copper and palladium salts

The influence of the central metal atom and acid residue in a molecule of organometallic compound Ph₃MX₂ (M = Bi, Sb; X = Cl, Br, OAc, O₂CEt) on the direction and yield of dephenylation products in a methyl acrylate— methanol system in the presence of Cu(OAc)₂ and Na₂PdCl₂(OAc)₂ was studied at 50 °C in acetonitrile. The main product of dephenylation of the antimony compounds is methyl cinnamate (yield 0.31–1.59 moles per mole of the starting Ph₃SbX₂), while anisole (0.55–0.97 mol) and halobenzene (0.67–1.04 mol) are those for compounds Ph₃Bi(O₂CR)₂ and Ph₃BiHal₂, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 655–658, April, 2006.     

Benzoylation of methyl acrylate. Crystal and molecular structure of (methyl-3-benzoylacrylate)bis(triphenylphosphine)nickel(0)benzene (1:1) solvate

Summary The benzoylation of methyl acrylate with benzoyl chloride and zerovalent nickel has been studied and an x-ray structural analysis of the intermediate (PPh₃)₂Ni(C₁₁H₁₀O₃) · C₆H₆ complex solvate (1:1) has been carried out. The crystals are triclinic with unit cell dimensions:a 12.488(5),b 20.569(7),c 9.733(4)Å; 9().08(5), 65.54(5), 75.85(5)°; space group P ; finalR factor 0.040. The nickel is in a trigonal environment and the olefinic fragment of the methyl 3-benzoylacrylate involved in the coordination is twisted from the plane formed by the metal and the phosphorus by 8.5°. An expected C=C lengthening in the organic ligand is observed.     

聚丙烯酸甲酯-丝胶双亲纳米微球的合成及其应用

以叔丁基过氧化氢(TBHP)为引发剂,通过丝胶(SS)与丙烯酸甲酯(MA)的接枝共聚反应制得了以PMA接枝链为核,SS为壳的双亲纳米微球(PMA-SS),其结构经IR,透射电镜和激光衍射粒度分析仪表征。结果表明:MA成功地接枝到SS大分子链上;PMA-SS具有明显的核-壳结构,粒径110nm～130nm,粒径分布相对较窄。初步探讨了PMA-SS对三价铬离子(Cr3 )的吸附性能。     

Polymerization of methyl methacrylate using bis(β‐ketoamino)nickel(II)–MAO catalytic systems

The polymerization of methyl methacrylate (MMA) was investigated using a series of bis(β‐ketoamino)nickel(II) complexes in combination with methylaluminoxane in toluene solution. The binary catalyst is necessary for initiating MMA polymerization and producing PMMA with high molecular weights but broad molecular weight distributions. The effects of reaction temperature and Al:Ni molar ratios on the polymerization of MMA were examined in detail. Both steric bulk and electronic effects of the substituents around the imino group in the ligand on MMA polymerization activities could be observed. Relative to electronic effects, the steric hindrance of the ligands displayed a more significant effect on the catalytic activities, with the catalytic activity sequence observed in the order 4 > 1 > 2 > 3 > 5 > 6. Structural analyses of the polymers by ¹³C NMR spectra indicate that polymerization yields PMMA with a syndiotactic‐rich atactic microstructure. Copyright © 2006 John Wiley & Sons, Ltd.     

Microstructural study of poly(methyl methacrylate-co-n-propyl acrylate) by 13C NMR

Analysis of carbonyl and β-CH₂ signals in the 100?MHz ¹³C NMR spectra of poly(methyl methacrylate-co-n-propyl acrylate) (PMMA/nPrA), provided distribution of configurational-compositional sequences for a series of the copolymer samples of different composition at pentad level for carbonyl signal and hexad level for the backbone methylene carbons. Computer simulation of the spectra based on incremental calculation of the chemical shifts for individual sequences provided very good agreement with the experimental spectra.     

DSC study of the miscibility of poly(methyl acrylate)-polystyrene sequential interpenetrating polymer networks

The phenomenon of forced compatibilization has been studied in poly(methyl acrylate)-polystyrene PMA-i-PS sequential interpenetrating polymer networks, IPNs, using differential scanning calorimetry. Both networks in the IPN were prepared using the same amount of ethylene glycol dimethacrylate, EGDMA, as crosslinking agent. The samples were subjected to thermal treatments which included annealing at different ageing temperatures T _a, for 300 min. From the DSC curves, recorded on heating the enthalpy loss during the isothermal annealing, Δh _a was calculated. The dependence of Dh _a with the annealing temperature was used to define the temperature interval in which the conformational mobility is significant. The comparison of the Δh _a(T _a) curves obtained in an IPN and the results obtained with the pure component homo-networks with the same crosslinking density reveal some details of the miscibility of the IPN. In the case of the IPN crosslinked with 10% EGDMA, two peaks are apparent in the Δh _a(T _a) curve, but the high-temperature peak is shifted towards lower temperatures compared to that of the polystyrene network while the low-temperature one is nearly at the same temperature than the one of the poly(methyl acrylate) homonetwork. This means that compatibilization is not complete and phase separation still exists even at this high crosslinking density. The different behaviour of the high and low temperature transitions can be explained by the dynamic heterogeneity of the sample, i.e. by the different length of cooperativity of the conformational rearrangements of PMA and PS domains at any temperature. This revised version was published online in July 2006 with corrections to the Cover Date.     

A DFT study on the 1,3-dipolar cycloaddition reactions of C-(methoxycarbonyl)-N-methyl nitrone with methyl acrylate and vinyl acetate

In the 1,3-dipolar cycloaddition of glyoxylic nitrones with electron-poor and electron-rich alkenes, the configurational instability of the nitrone leads to parallel models when regio- and stereoselectivities are rationalized. The energetics of the cycloaddition reactions have been investigated through molecular orbital calculations at the B3LYP/6-31-G(d) theory level. By studying different reaction channels and reagent conformations, leading to a total of sixteen transition structures for each dipolarophile, the regio- and stereochemical preferences of the reaction are discussed.