The Polymerization of Methyl Methacrylate with a New Nd(O—i-Pr)_3—AI(i-Bu)_3Catalyst System

ＴｈｅＰｏｌｙｍｅｒｉｚａｔｉｏｎｏｆＭｅｔｈｙｌＭｅｔｈａｃｒｙｌａｔｅｗｉｔｈａＮｅｗＮｄ（Ｏ—ｉ┐Ｐｒ）３—ＡＩ（ｉ┐Ｂｕ）３ＣａｔａｌｙｓｔＳｙｓｔｅｍ＊ＳＵＮＪｕｎ－ｑｕａｎ（Ｄｅｐｔ．ｏｆＰｏｌｙｍ．Ｓｃｉ．ａｎｄＥｎｇｉｎｅｒｉｎｇ,Ｚ...     

Surface Acidic Properties of Loaded Heteropoly Acid and Preparation of Dimethylether by Catalyzed Dehydration of Methyl Alcohol

ＳｕｒｆａｃｅＡｃｉｄｉｃＰｒｏｐｅｒｔｉｅｓｏｆＬｏａｄｅｄＨｅｔｅｒｏｐｏｌｙＡｃｉｄａｎｄＰｒｅｐａｒａｔｉｏｎｏｆＤｉｍｅｔｈｙｌｅｔｈｅｒｂｙＣａｔａｌｙｚｅｄＤｅｈｙｄｒａｔｉｏｎｏｆＭｅｔｈｙｌＡｌｃｏｈｏｌ＊ＨＵＡＲｕｉ－ｎｉａｎ，Ｗ...     

Syntheses of 3－Methyl－1－propyl－4－piperidoneand1－Methyl－3，7－dipropyl－3，7－diazabicyclo［3，3，1］nonan－9－one

Ｓｙｎｔｈｅｓｅｓｏｆ３－Ｍｅｔｈｙｌ－１－ｐｒｏｐｙｌ－４－ｐｉｐｅｒｉｄｏｎｅａｎｄ１－Ｍｅｔｈｙｌ－３,７－ｄｉｐｒｏｐｙｌ－３,７－ｄｉａｚａｂｉｃｙｃｌｏ［３,３,１］ｎｏｎａｎ－９－ｏｎｅＷＡＮＧＹｕ－ｈｕａｎ,ＷＡＮＧＧｕｏ－ｊｉａ,Ｚ...     

Crystal Structure of 3－Methyl－9－（O，O－Diethylphosphoryl） Methyl－1，6，12－Trioxa－9－Aza－5－Germaspiro［4，7］Dodecan－2－One

ＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ３－Ｍｅｔｈｙｌ－９－（Ｏ，Ｏ－Ｄｉｅｔｈｙｌｐｈｏｓｐｈｏｒｙｌ）Ｍｅｔｈｙｌ－１，６，１２－Ｔｒｉｏｘａ－９－Ａｚａ－５－Ｇｅｒｍａｓｐｉｒｏ［４，７］Ｄｏｄｅｃａｎ－２－Ｏｎｅ￥ＣｈｅｎＲｕ－ｙｕ；ＬｉｕＬｕ...     

Solid State Synthesis and Crystal Structure of 3－Methyl－1－phenyl－4－phenylbenzoylmethylene－5－pyrazolone

ＳｏｌｉｄＳｔａｔｅＳｙｎｔｈｅｓｉｓａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ３－Ｍｅｔｈｙｌ－１－ｐｈｅｎｙｌ－４－ｐｈｅｎｙｌｂｅｎｚｏｙｌｍｅｔｈｙｌｅｎｅ－５－ｐｙｒａｚｏｌｏｎｅＤｕＤａ－Ｍｉｎｇ；ＭｅｎｇＳｈｕａｎｇ－Ｍｉｎｇ；Ｗａｎｇ...     

Synthesis and Crystal Structure of Bis［Bis（Cyclopentylcyclopentadienyl）Methyl－Erbium］［（C_5H_9C_5H）_4）_2ErCH_3］_2

ＳｙｎｔｈｅｓｉｓａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ　Ｂｉｓ［Ｂｉｓ（Ｃｙｃｌｏｐｅｎｔｙｌｃｙｃｌｏｐｅｎｔａｄｉｅｎｙｌ）Ｍｅｔｈｙｌ－Ｅｒｂｉｕｍ］［（Ｃ_５Ｈ_９Ｃ_５Ｈ）_４）_２ＥｒＣＨ_３］_２ＪｉｎＪｉ－Ｚｈｕ；ＺｈｕａｎｇＸｉｕ－...     

Crystal and Molecular Structure of 3，4－diphenyl－5－ethyl－5－methyl－1，3，4－diazaphospholidin－2－thione－4－oxide

ＣｒｙｓｔａｌａｎｄＭｏｌｅｃｕｌａｒＳｔｒｕｃｔｕｒｅｏｆ３，４－ｄｉｐｈｅｎｙｌ－５－ｅｔｈｙｌ－５－ｍｅｔｈｙｌ－１，３，４－ｄｉａｚａｐｈｏｓｐｈｏｌｉｄｉｎ－２－ｔｈｉｏｎｅ－４－ｏｘｉｄｅ￥ＦｅｎｇＫｅ－Ｓｈｅｎｇ；ＣｈｅｎＲｕ－Ｙｕ（Ｉ...     

Classified Subject Contents

Ａ .ＳｙｎｔｈｅｔｉｃＯｒｇａｎｉｃＣｈｅｍｉｓｔｒｙＡＣｏｎｖｅｎｉｅｎｔＳｙｎｔｈｅｓｉｓｏｆ 2 Ａｒｙｌａｍｉｎｏ 2 ｓｅｌｅｎａｚｏｌｉｎ 4 ｏｎｅｓＺＨＡＯ ,Ｈｕａ Ｒｏｎｇ ;ＺＨＡＮＧ ,Ｙｕ Ｈｏｎｇ ;ＹＵ ,Ｑｉｎｇ Ｓｅｎ (5 99)……………ＡＮｅｗＡｐｐｒｏａｃｈｔｏＭｅｔｈｙｌ 4 Ａｍｉｎｏ 1 ｍｅｔｈｙｌｐｙｒｒｏｌｅ 2 ｃａｒｂｏｘｙｌａｔｅＨｙｄｒｏｃｈｌｏｒｉｄｅＺＨＡＮＧ ,Ｚｈｅｎｇ Ｂｏ ;ＮＩＥ ,Ｊｉｎ (5 19)…………………ＡＮｅｗＭｅｔｈｏｄｆｏｒｔｈｅＳｙｎｔｈｅｓｉｓ…     

Crystal Structure of N－（N－Phenylthiazotone）imino－O－ethyl－N－isopropylaminothiophosphate

ＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆＮ－（Ｎ－Ｐｈｅｎｙｌｔｈｉａｚｏｔｏｎｅ）ｉｍｉｎｏ－Ｏ－ｅｔｈｙｌ－Ｎ－ｉｓｏｐｒｏｐｙｌａｍｉｎｏｔｈｉｏｐｈｏｓｐｈａｔｅ￥ＹａｎｇＨｕａ－Ｚｈｅｎｇ；ＬｉｕＨｕａ－Ｙｉｎ；ＷｕＹｅ（Ｉｎｓｔｉｔｕｔｅｏｆ...     

1β—Methyl Carbapenem中间体的合成

综述了１β－Ｍｅｔｈｙｌ Ｃａｒｂａｐｅｎｅｍ中间体的合成方法，重点强调了如何构筑１位β构型的甲基。参考文献３７篇。     

Polymerization of Methyl Methacrylate Using Acridone-Bromine Combination as the Photoinitiator

The photopolymerization of methyl methacrylate (MMA) in visible light was studied at 40°C using the acridone-bromine (acridone-Br₂) combination as the photoinitiator. The polymerization was found to proceed via a free radical mechanism, and the radical generation process was considered to follow an initial complexation reaction between monomer and each initiator component (acridone and Br₂), followed by further interaction between these two initiator-monomer complexes. Kinetic data indicated a lower-order dependence of R on initiator concentrations (initiator exponent < 0.5). Initiator-dependent chain termination was signifi-cant along with the usual bimolecular mode of chain termination. The monomer exponent varied from about 1.00 to 2.00, depending on the nature of solvents used. The nonidealities in this system were also analyzed.     

Photopolymerization of Methyl Methacrylate Using Iodine Monochloride as the Photoinitiator

Iodine monochloride, IC1, can easily induce photopolymerization of MMA at 40° C under visible light. Initiator order and monomer order are 0.5 and 2, respectively, at low [IC1], while the corresponding values at high [IC1] are 0 and 3. Kinetic and other data indicate a radical polymerization mechanism that involves complexation of monomer molecules with IC1, which is second order in [M], prior to radical generation. Termination of polymerization proceeds bimolecularly at low [IC1], and unimolecularly, involving reaction with the initiator at high [IC1] (initiator termination).     

Use of an Internal Keto-Imino Compound as the Photoinitiator in the Polymerization of Methyl Methacrylate

Photopolymerization of MMA in visible light was studied at 40°C using acridone as the photoinitiator. The polymerization was found to proceed via a free radical mechanism and the radical generation process was considered to follow an initial complexation reaction between monomer and acridone. Kinetic data indicated a lower order dependence of R_p on the initiator concentration (initiator exponent < 0.5). Initiator-dependent chain termination was significant along with the usual bimolecular mode of chain termination. The monomer exponent varied from about 1.0 to 1.5, depending on the nature of the solvent used. The nonidealities in this case were also analyzed.     

Polymerization of Methyl Methacrylate by Organometallic Compounds. V. Dark Stoichiometric and Polymerization Reactions between Trialkylaluminums and Methyl Methacrylate

The stoichiometric reaction products of the reaction of triethylaluminum and methyl methacrylate (MMA) derive from a different complex to that responsible for the photosensitized, radical polymerization. The stoichiometric products are the result of nucleophilic attack on the carbonyl group of MMA (1,2 addition). No 3,4 nucleophilic adducts are found and it is questioned whether the one product usually believed to be the result of conjugate (1,4) attack does so arise. The reactions have been followed, in situ, using 60 MHz NMR and mechanisms are discussed. The nucleophilic addition reactions do not develop into an anionic polymerization chain. The equilibrium constants governing MMA-triethylaluminium complex formation are such that the 1:1 complex, the precursor of radical polymerization, prevails overwhelmingly in MMA-rich mixtures and the precursor of stoichiometric, nucleophilic, addition reactions prevails in A1-rich mixtures. The validity of diagnostic tests for polymerization mechanism based on the nature of concomitant, low molecular weight products is discussed.

It is confirmed that triethylaluminium does not initiate MMA polymerization in the dark over the temperatures 233-333°K. We find diisobutylalumin-ium hydride inert, in dark or light, at 298 and 333°K. Triisobutylaluminium only initiates MMA when illuminated at 298°K, but at 333°K there is also a significant dark rate. Preliminary copolymerization experiments, devised to elucidate the mechanism of this dark polymerization, suggest that, as in the case of the photo-sensitized, triethylaluminium-initiated, radical polymerization, it proceeds from a 1:1 MMA: trialkylaluminium complex.     

Anionic Polymerization of Methyl Methacrylate in the Presence of Piperidine

Anionic polymerization of methyl methacrylate (MMA) initiated by lithium tert-butoxide (t-BuOLi) was investigated in different mixtures of benzene and piperidine. The latter compound activates the associated alkoxide, as evidenced by the observed increase in the rate of polymerization, proportional to piperidine concentration and also by the lowering of the overall kinetic order of the polymerization reaction with respect to initial monomer concentration. However, at higher piperidine concentration the rate of the polymer growth significantly decreases after a short period of time; a probable reason for this retardation or termination effect is the decay of active growth centers by a termination reaction with the methacrylate carbonyl group. The molecular weight of the polymer is significantly lowered by even a small addition of piperidine as a result of increased initiator efficiency that leads to a higher absolute concentration of active centers and approaches the theoretical limit given by the stoichiometric ratio of monomer and initiator concentrations. The microstructure of the product is affected by the presence of the polar solvent to a considerably lesser degree than in the case of classical alkylmetal initiators. The isotacticity slowly decreases with piperidine concentration over the whole investigated range. The high stability of the complex active center of growth formed by the alkoxide initiator and also the gradual change in the character of the ionic pair at the end of the growing polymer chain are responsible for the relatively small changes of the microstructure.     

Homogeneous Solution Reverse Atom Transfer Radical Polymerization of Methyl Methacrylate

A homogeneous reverse atom transfer radical polymerization (RATRP) of methyl methacrylate (MMA) was successfully carried out in N, N-dimethylformamide(DMF) (25%, v/v) at 69°C, using an initiating system azobisisobutyronitrile (AIBN)/CuBr₂/N, N, N′, N″, N″-pentamethyldiethylenetriamine (PMDETA). The kinetics of homogeneous solution polymerizations showed linear first-order rate plots, indicating a constant number of growing species throughout the polymerization as well as a negligible contribution of termination or transfer reactions; a linear increase of the number-average molecular weight with conversion, and relatively low polydispersities, but low initiator efficiency. The dependence of the rate of polymerization on the concentrations of initiator, catalyst, ligand and temperature were presented.     

室温下甲基丙烯酸甲酯原子转移自由基乳液聚合反应研究

以卤化亚铜（CuX）/1,10-邻二氮菲（phen）配合物为催化剂、2-溴代异丁酸 乙酯（EBiB）为引发剂、十二烷基磺酸钠（SLS）为乳化剂,进行了甲基丙烯酸甲 酯（MMA）的原子转移自由基乳液聚合（ATRP）反应。结果表明,与较高温度（70 - 90 ℃）下的聚合反应相比,室温（25 ℃）时聚合反应有更好的可控性,通过 外加钝化剂的复合催化引发体系CuBr/CuBr_2/phen/EBiB或利用CuCl/phen/EBiB催 化引发体系的“卤素交换反应”,可进一步改善聚合反应的可控性。紫外发光谱测 定结果表明,CuBr/phen配合物在MMA相中的分配倾向随着温度的降低而增大,使得 室温下MMA的乳液ATRP保持了较好的可控性和较快的反应速度。     

Kinetic Investigation on the Photopolymerization of Methyl Methacrylate Using Iodine Trichloride as Initiator

The photopolymerization of MMA in visible light was studied at 45°C using IC1₃ as the photoinitiator. The initiator exponent was found to be 0.16 and the monomer exponent varied between 1.0 to 1.50, depending on the nature of the solvent. Analysis of the data revealed that the polymerization was induced by a free radical mechanism. Nonideality of the kinetics was explained on the basis of 1) Monomer-dependent chain initiation and 2) Initiator-dependent chain termination via degradative initiator transfer.     

Aqueous Polymerization of Methyl Methacrylate Initiated by Pyridine-Sulfur Dioxide Complex

The aqueous polymerization of MMA was studied kinetically at 40° C using low concentrations of Py-SO₂ complex as initiator. For [Py-SO₂] < 2 × 10^?2 mol/L, R_p ∞ [PY-SO₂]^0.5 [M]^1.5, and for [Py-SO₂] > 2 × 10^?2 mol/L, R_p ∞ [Py-SO₂]^0,0[M]^1.08. Polymerization is considered to proceed by a radical mechanism. The radical generation or the initiation step is believed to proceed through equilibrium complexation between the Py-SO₂ complex and monomer molecules. For [Py-SO₂] < 2 × 10^?2 mol/L, the polymerization is characterized by bimolecular termination. Above this [Py-SO₂], chain termination by a degradative initiator transfer process assumes prominence.     

基于RAFT过程的MMA可控自由基聚合及嵌段共聚物的合成

用二硫代酯调控的可逆加成-裂解链转移过程(RAFT)研究了MMA的聚合动力学及分子量分布,分析了引发剂浓度和二硫代酯浓度对反应速度及可控性的影响.用RAFT方法合成了嵌段共聚物PMMA-b-PS及带有自旋标记的嵌段共聚物PMMA-b-PS.