脂肪胺类化合物的13C核磁共振波谱模拟

对脂肪胺类化合物的13C核磁共振波谱进行了模拟,所用方法为数学模型法,为此,提取了共振碳原子所处化学环境的拓扑特征,几何特征及电子特征,运用变量最优子集回归法对变量进行了选择,用多元回归法构造了数学模型,得到了比较满意的预测结果。     

Determination of the Microstructure of Some Methyl Methacrylate-Butadiene Copolymers by 220 MHz Proton Magnetic Resonance Spectroscopy

Abstract

Proton magnetic resonance (PMR) spectroscopy at 220 MHz has been used to gain information about the relative proportions of various methyl methacrylate centered triads and pentads in some methyl methacrylate (MMA)-butadiene (BU) copolymers prepared with a free-radical catalyst. The PMR peaks used are the MMA α-methyl peaks recorded using CDCL₃ as solvent, and the MMA α methyl peaks recorded using C₅D₅N as solvent. Measured triad and pentad fractions are in good agreement with those calculated from the reactivity ratios r₁ = 0.17 and r₂ = 0.60, where MMA = Monomer 1. Surprisingly, the α-methyl peaks provide information also about the ratio of cis-1,4- to trans-1, 4-butadiene units in the copolymer. Proportions of 1,2-butadiene units are obtained from the relative areas of peaks due to vinyl and vinylene protons.     

Dispersion Polymerization of Methyl Methacrylate in Supercritical Carbon Dioxide in the Presence of Random Copolymers

Summary: Statistical random copolymers of 1H,1H‐perfluorooctyl methacrylate and 2‐dimethylaminoethyl methacrylate, poly(FOMA‐co‐DMAEMA), effectively stabilized the dispersion polymerization of methyl methacrylate in supercritical carbon dioxide. Free‐flowing, micron‐sized spherical PMMA particles could be produced with poly(FOMA‐co‐DMAEMA) containing 34 w/w% FOMA.

SEM image of PMMA particles prepared with poly(FOMA‐co‐DMAEMA) (34:66).     

Copolymerization and Copolymers of 2,4,5-Tribromostyrene with Methyl Acrylate and Methyl Methacrylate

Abstract

2,4,5-Tribromostyrene (TBSt) was copolymerized with methyl acrylate (MA) or methyl methacrylate (MMA) in a toluene solution using 2,2′-azobisisobutyronitrile as free radical initiator. The copolymerization reactivity ratios were found to be for the system TBSt / MA r₁= 7.4 ± 1.2 (TBSt) and r₂= 0.1 ± 1.4 (MA) and for the system TBSt / MMA r₁ = 1.8 ± 0.2 (TBSt) and r₂ = 0.1 ± 0.2 (MMA). The e and Q values were also calculated. The initial rate of copolymerization, as well as molecular weight of the obtained copolymers for both system linearly increase as the content of TBSt in the monomer mixture increases. Similar behavior has also been established for the course of the copolymerization reactions to high conversions. The resulting copolymers rapidly decompose at temperatures 20–800°C above the decomposition of corresponding (metha)crylate hompolymers. However, the glass transition temperature increases markedly with increasing TBS content.     

相似分析-13 C核磁共振法鉴定(10,12,14)-十六碳共轭三烯-1-乙酸酯异构体的几何构型

报道了利用相似分析-13C核磁共振法确定(10,12,14)-十六碳共轭三烯-1-乙酸酯异构体的几何构型。该方法将共轭三烯6个烯碳的特征化学位移作为相似分析的基本参数,计算样品与每一个几何异构体间的相似指数,根据最大相似指数确定样品最可能的构型。该方法简便,结果满意。     

苯乙烯-甲基丙烯酸甲酯嵌段共聚物的合成与表征

采用阴离子聚合技术合成了一系列苯乙烯-甲基丙烯酸甲酯的两嵌段共聚物(PS－b－PMMA)．采用GPC、FTIR、NMR(¹HNMR、¹³CNMR和固体NMR)和DMA等手段进行了表征．结果表明,所得产物为高分子量、窄分布、具有微相分离结构的两嵌段共聚物．     

Alternating Copolymers of Limonene with Methyl Methacrylate: Kinetics and Mechanism

The radical copolymerization of limonene (optically active) with methyl methacrylate in xylene at 80±0.1°C for 1 hr, initiated by benzoyl peroxide (BPO) yield alternating copolymer(s), under the inert atmosphere of nitrogen, as evidenced by reactivity ratios r₁ (MMA)=0.07 and r₂ (limonene)=0.012 using the Kelen–Tüdos method. The kinetic expression is Rα[I]^0.5[MMA]^1.0[Lim.]^?1.0. The decrease in the rate of polymerization with increase in concentration of limonene is due to penultimate unit effect. The overall energy of activation is calculated as 49 kJ/mole. FTIR of the copolymer(s) shows the characteristic frequencies at 1732.40 and 2951.40 cm^?1 due to –OCH₃ of MMA and aromatic C–H stretching of limonene, respectively. ¹H NMR spectra shows peak at 3.8–4.1 δ and 5.3–5.6 δ due to –OCH₃ of MMA and trisubstituted olefinic protons [–CH=CH–CH₂–] of limonene, respectively.     

丝胶-甲基丙烯酸甲酯接枝共聚物的合成与表征

在酸性水介质中,以硝酸铈铵为引发剂合成了丝胶-甲基丙烯酸甲酯接枝共聚物,其结构经1H NMR,IR,SEM和GPC表征。用正交试验法考察了各因素对接枝共聚反应的影响,结果表明,单体浓度对接枝聚合反应的影响最大,反应时间的影响最小。     

聚甲基丙烯酸2,2,3,3-四氟丙酯及其单体与甲基丙烯酸甲酯共聚物的合成与表征

含氟甲基丙烯酸酯聚合物中的氟原子可使其折光指数n_D很低。这是光导纤维皮材的首要条件^[1]。这类材料的大分子主链与作为芯材使用的聚甲基丙烯酸甲酯(PMMA)具有相同的结构,因此其间的相容性和粘结性好,有利于光的全反射;其热稳定性也好^[2,3],可用于共挤出法制造塑料光导纤维.     

碳-13核磁共振法研究小皮伞多糖结构

采用＾１３Ｃ核磁共振法测定和确定了小皮伞多糖中的大分子葡聚糖,葡甘聚糖等３种多糖的一级结构,这些结果与组成分析和甲基化分析结果是一致的,确定了毫克级直接用＾１３Ｃ核磁共振法分析和检测多糖结构的方法。     

Acrylonitrile Copolymerizations. III. Flash Pyrolysis of Methyl Methacrylate and Styrene Copolymers

Flash pyrolysis of the copolymers acrylonitrile-methyl methacrylate and acrylonitrile-styrene has been carried out over the whole range of compositions, and yields of the monomers have been measured. In the first case, all of the methyl methacrylate is recovered as monomer except when a unit is isolated between two acrylonitrile segments. However, the yield in acrylonitrile monomer is lower; it corresponds to the units isolated between long sequences of methyl methacrylate plus the isolated acrylonitrile diads. The agreement between the calculated and experimental yields is excellent only if one takes into account the penultimate effects. In the second case, however, it is not possible to deduce a quantitative interpretation of the yields of either styrene or acrylonitrile monomers.     

N-对甲基苯基马来酰亚胺/甲基丙烯酸甲酯/丙烯腈乳液共聚物的合成与热性能

N-取代马来酰亚胺类(NPTMI)共聚物以其优异的耐热性而引起人们的重视,但对其共聚物的报道较少,本文采用完全滴加进料的乳液聚合方式合成了NPTMI／甲基丙烯酯甲酯(MMA)／丙烯腈(AN)的三元共聚物,用凝胶渗透色谱(GPC)表征了三元共聚物的平均分子量及其分布,并用示差扫描量热(DSC)、扭辫分析(TBA)及热重分析(TG)研究了共聚物的热行为。     

Some Factors Affecting the Photosensitized Polymerization of Methyl Methacrylate

The effects of sensitizer, alcohol, and reaction temperature on the photosensitized polymerization of methyl methacrylate in cyclohexane-alcohol mixtures were investigated. A maximum conversion was indicated at a certain concentration of alcohol in the mixture for the systems sensitized with quinones such as anthraquinone, 2-tert-butylanthraquinone, and α-naphthoquinone, while it was not observed for the benzophenone-sensitized system. The concentration of alcohol corresponding to the maximum conversion increased in the order methanol < ethanol < n-propanol < n-butanol, and shifted to the lower side by raising the reaction temperature from 20 to 40°C. Based on the absorption and ESR spectra of irradiated solution of quinones, reasons for maximum conversion at an optimum concentration of alcohol are discussed.     

Endgroups in Copolymers of Acenaphthylene with Methyl Methacrylate Prepared with Azoisobutyronitrile as Initiator

Copolymers of acenaphthylene (ACN) with methyl methacrylate (MMA) have been prepared with azobis(isobutyronitrile-β, β-¹³C₂) as initiator, The endgroups derived from the initiator have been examined by ¹³C-NMR spectroscopy; those attached to ACN units have been distinguished from those attached to MMA units and quantitative comparisons of their numbers have been made. It has been deduced that at 60°C ACN is four times as reactive as MMA toward the (CH₃)₂ C(CN) radical. The marked preference for initiation involving ACN means that, for all copolymers, the ratio of ACN to MMA is appreciably greater for the sites adjacent to the (CH₃)₂ C(CN)– endgroups than for the whole copolymer.     

Effect of Cathode Potential on Electrosynthesis and Physicochemical Properties of Styrene and Methyl Methacrylate Copolymers

The voltammetry, ESR and UV spectroscopy methods and quantum chemical calculations (PPDP/2) are used to determine the nature of active centers, the anionic mechanism of electrochemical copolymerization (ECP) of styrene (St) and methyl methacrylate (M) at the cathode surface, and the radical-anion mechanism in aprotic solvents. The composition, microstructure, and dielectric properties of copolymers are determined by the cathode potential, which is due to a change in the nature of inducing species (M°^–, °M–M^–, ^–M–M^–, St^2–) and in the ratio of their concentrations during ECP.     

Synthesis and Investigation of Copolymers of Glycidyl Methacrylate and Methyl Pheophorbide a in a Solution

Russian Journal of General Chemistry - Copolymers of glycidyl methacrylate and methyl pheophorbide a of different compositions were synthesized by radical copolymerization in toluene and THF...     

13C-Nuclear Magnetic Resonance spectroscopy as a probe of enzyme environment—II: Effect of solvent and pH on 13C-chemical shifts in derivatized amino-acid models

The synthesis and characterization of side-chain derivatives of amino- and carboxy-protected lysine, serine and cysteine, and of two tripeptides is reported. Broad-band proton-decoupled ¹³C-nuclear magnetic resonance spectra have been determined and in almost all cases, each carbon resonance has been unambiguously assigned by a combination of off-resonance and specific decoupling techniques. The effect of solvent and pH on chemical shifts is discussed. The objective of these studies is to provide models relevant to the use of ¹³C-labelled electrophilic inhibitors as probes of enzyme active-site environment.     

超支化聚苯乙烯-线型聚苯乙烯-超支化聚甲基丙烯酸甲酯三嵌段聚合物的合成与表征

合成了超支化聚苯乙烯-线型聚苯乙烯-超支化聚甲基丙烯酸甲酯三嵌段聚合物(HPS-b-LPS-b-HPMMA). 首先分别合成了带有炔基和溴的三硫代碳酸酯(ATC和BTC), 然后通过苯乙烯(St)的可逆加成-断裂链转移(RAFT)聚合, 制得端炔基和端基溴的线型聚苯乙烯大分子RAFT试剂, 然后将大分子RAFT试剂的溴末端转化为叠氮末端. 接着在大分子RAFT试剂存在情况下, 通过自缩合原子转移自由基共聚合(SCATRCP)分别制得端炔基超支化聚苯乙烯-线型聚苯乙烯(HPS-b-LPS)和端叠氮基超支化聚甲基丙烯酸甲酯-线型聚苯乙烯(HPMMA-b-LPS)两嵌段聚合物. 最后将两种两嵌段聚合物通过点击(click)反应偶合, 得到不对称的超支化-线型-超支化三嵌段聚合物HPS-b-LPS-b-HPMMA. 核磁共振氢谱(¹H NMR)、凝胶渗透色谱(GPC)结果表明, 所得产物分子量可控, 得到了预期结构的聚合物.     

梳状丙烯酸酯类共聚物凝胶电解质的传输性能与自由体积

用三种分子量大小不等的聚乙二醇单甲醚(PEGME)与甲基丙烯酸甲酯-马来酸酐共聚物[P(MMA-co-MAh)]反应,制备了三种支链长度不等的梳状共聚物(MMA/MAh-g-PEGME), 并以此为基体, 加入增塑剂碳酸丙烯酯(PC)和高氯酸锂(LiClO₄), 采用溶剂浇铸法制备了三种凝胶聚合物电解质(GPE)膜, 研究了其离子传输性能, 发现该聚合物凝胶电解质的离子传输机理符合VTF (Vogel-Tamman-Fulcher)方程, 即离子传输性能与凝胶体系自由体积的大小有关; 采用正电子湮没寿命谱仪(PALS)研究了GPE 体系的自由体积特性, 获得了各支链长度不同的共聚物凝胶电解质的自由体积分数, 分析各自由体积与离子传输性能之间的关系, 建立了共聚物结构、凝胶聚合物自由体积及其传输性能之间的关系. 发现梳状共聚物支链长度越长, 凝胶电解质的自由体积越大, 离子传输性能越高.     

4-叔丁基苯乙烯和甲基丙烯酸甲酯共聚物磁性吸油树脂

以4-叔丁基苯乙烯(t BS)和甲基丙烯酸甲酯(MMA)为单体,二乙烯基苯(DVB)为交联剂,与双键修饰的Fe3O4纳米粒子共聚,制备了一系列基于t BS和MMA的磁性高分子吸油树脂.用红外光谱(FTIR)、X-射线衍射(XRD)、光学显微镜(OM)、扫描电子显微镜(SEM)、接触角(CA)和比表面积测试等技术对样品进行了表征.详细考察了两单体配比、交联剂用量对树脂的吸附容量、吸附速率的影响规律.实验发现,当两单体用量分别为2 m L,交联剂为0.5 m L时,磁性吸油树脂的吸油性能达到最好.