Electron-impact studies XCII–Negative ion-molecule reactions in anhydride systems. Perfluoroacetic anhydride with succinic,maleic and phthalic anhydrides. An ion cyclotron resonance study

The trifluoroacetate anion undergoes reaction with succinic, maleic and phthalic anhydrides to yield 1 : 1 adducts. The molecular anions of maleic and phthalic anhydride also undergo reaction with perfluoroacetic anhydride to produce [CF₃CO₂]^?· Maleic anhydride parent ions produce [M + CF₃CO·]^? ions when allowed to react with perfluoroacetic anhydride.     

Fe-Al-α,α′-联吡啶络合催化聚合马来酸酐与环氧氯丙烷研究

研究了马来酸酐与环氧氯丙烷交替共聚，及Ｆｅ（ａｃａｃ）３ Ａｌ（ｉ Ｂｕ）３ α，α’ 联吡啶络合物（ａｃａｃ＝ 乙酰丙酮） 催化马来酸酐（ＭＡ） 和环氧氯丙烷交替共聚的特征，并用红外光谱，核磁共振谱研究了共聚物的结构。动力学研究表明共聚反应与单体浓度和催化剂浓度均呈一级关系。     

马来酸酐与乙酸乙烯酯交替共聚合反应的研究

本文研究了马来酸酐（MAn）在过氧化苯甲酰（BP）引发作用下与醋酸乙烯酯（VAc）的交替共聚反应。红外光谱证明了交替共聚物的结构，分析结果表明共聚物是由反应单体技1：1摩尔比例组成。当c（BPO）＝6．8×10~（－3）moi／L，c（VAc）＝3．4×10~（－3）mol／L，p（MAn）＝32．7g／L，63～65℃反应18小时，转化率可达92％以上。     

An example of quality control of fine chemical intermediates: related impurity analysis of industrial phthalic anhydride by reversed-phase high-performance liquid chromatography

A reliable reversed-phase high-performance liquid chromatographic method has been developed for analysis of related impurities in industrial phthalic anhydride (PA). Maleic acid (hydrolysis product of maleic anhydride), phthalimide, and benzoic acid were separated from phthalic acid (Pa, hydrolysis product of PA) on a C₁₈ column by gradient elution with acetonitrile and 0.1% (v/v) aqueous perchloric acid solution. This method is simple, sensitive, and accurate, and has been successfully applied to quality control of PA for industrial use.     

Grafting of maleic anhydride to hydrocarbons below the ceiling temperature

Maleic anhydride has been grafted to eicosane and squalane at 60–80°C using 1,2-dichlorobenzene as solvent and benzoyl peroxide as initiator. These hydrocarbons are low molecular weight models for hydrocarbon polymers containing secondary and tertiary hydrogen atoms. In the absence of the hydrocarbon and with monomer concentrations of the order of 1M, low molecular weight poly(maleic anhydride) is formed. On addition of the hydrocarbon, the main product is grafted material and very little homopolymer is formed. The grafts consist primarily of single succinic anhydride units but some of them are short poly(maleic anhydride) chains. Ceiling temperature considerations control the formation of homopolymer in the absence of hydrocarbon substrate. In the presence of eicosane or squalane, initiation of grafting proceeds by hydrogen abstraction from the hydrocarbon. The main factor controlling graft length is then the ratio of the rates of intramolecular hydrogen abstraction and of monomer addition to succinic anhydride radicals © 1995 John Wiley & Sons, Inc.     

Grafting of maleic anhydride to n-eicosane

Maleic anhydride was grafted to the linear hydrocarbon, n-eicosane, at 165°C in the presence of the free radical initiator, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne. The anhydride has a low solubility in eicosane and a multiple addition procedure was adopted. Grafted product which separated from the reaction mixture was fractionated and analyzed. The fractions contained on average 2–5.5 anhydride units/eicosane residue. ¹H- and ¹³C-NMR studies show that the grafts consist of single succinic anhydride rings. At the concentrations of maleic anhydride chosen for homogeneous reaction ( < 0.02 M) and at 165°C, poly(maleic anhydride) is above its ceiling temperature, so that succinic anhydride radicals cannot add maleic anhydride to form polymer side chains. Instead, these radicals abstract hydrogen atoms to yield grafts consisting of single anhydride units.     

改性淀粉/PVA生物降解材料性能的研究

以BPO为引发剂、正庚烷为溶剂在66℃下制得马来酸酐接枝淀粉。将其与聚乙烯醇(PVA)、增塑剂及加工助剂等于HAAKE密炼机中共混,制备了可生物降解热塑性淀粉塑料。研究了接枝改性淀：粉／PVA共混物的力学性能、生物降解性能及热性能等,并用SEM研究了共混物的微观形态。结果表明接枝改性淀粉／PVA共混物拉伸强度为27．57Mpa,60d失重率达65．1％。     

高效液相色谱法分离和测定酒石酸和马来酸

１引言 酒石酸（２,３一二羟基丁二酸）和马来酸（顺丁烯二酸）都是重要的有机化工原料,它们被广泛地应用于有机合成和其它化工生产领域［１］． 酒石酸的制备常用钨酸作为催化剂,由马来酸识水溶液与过氧化氢进行环氧化反应再经水解精制而成,其中常含有微量的没有反应的马来酸,因此,建立有效的分离和测定酒石酸和马来酸的方法,对于酒石酸生产条件的选择与控制,以及产品的质量检测等都有十分重要的意义． 目前尚未发现有关同时分离和测定酒石酸和马来酸的文献报道．我们首次采用反相高效液相色谱法,跟踪监测了酒石酸生产过程中的物…     

Siliciumorganische verbindungen: LXXVIII. Reduktive silylierung von konjugierten trienen zu 1,6-disilyl-dienen

The reductive silylation of 1,3,5-hexatriene (I) with trimethylsilyl chloride and magnesium affords 74% disilylhexadienes, consisting of 8% 1,4-bis(trimethylsilyl)-2,5-hexadiene (II) and 92% 1,6-bis(trimethylsilyl)-2,4-hexadiene (III). The isomers IIIa, IIIb and IIIc can be separated via the Dieis—Alder adducts. Maleic anhydride reacts with IIIa and IIIb to give the bis[(trimethylsilyl)methyl] derivatives of 4-cyclohexene-1,2-dicar?ylic acid anhydride (IVa and IVb), whereas IIIc does not react with maleic anhydride. By a reductive silylation reaction 3-methyl-l,3,5-hexatriene (V) gives the 1,6-bis-silylated 2,4-hexadienes VIa and VIb, which with maleic anhydride give the adducts VIIa and VIIb.     

马来酸酐聚合反应动力学的回归模拟

本文从函数变量相关内函规律出发，引用动力学物理概念，用数值逼近方法，对马来酸酐聚合反应的实验结果进行了模拟，得到了一符合实验规律的动力学方程。     

Thiol–Anhydride Dynamic Reversible Networks

The reaction of thiols and anhydrides to form ring opened thioester/acids is shown to be highly reversible and it is accordingly employed in the fabrication of covalent adaptable networks (CANs) that possess tunable dynamic covalent chemistry. Maleic, succinic, and phthalic anhydride derivatives were used as bifunctional reactants in systems with varied stoichiometries, catalyst, and loadings. Dynamic characteristics such as temperature-dependent stress relaxation, direct reprocessing and recycling abilities of a range of thiol–anhydride elastomers, glasses, composites and photopolymers are discussed. Depending on the catalyst strength, 100 % of externally imposed stresses were relaxed in the order of minutes to 2 hours at mild temperatures (80–120 °C). Pristine properties of the original materials were recovered following up to five cycles of a hot-press reprocessing technique (1 h/100 °C).     

Thiol–Anhydride Dynamic Reversible Networks

The reaction of thiols and anhydrides to form ring opened thioester/acids is shown to be highly reversible and it is accordingly employed in the fabrication of covalent adaptable networks (CANs) that possess tunable dynamic covalent chemistry. Maleic, succinic, and phthalic anhydride derivatives were used as bifunctional reactants in systems with varied stoichiometries, catalyst, and loadings. Dynamic characteristics such as temperature‐dependent stress relaxation, direct reprocessing and recycling abilities of a range of thiol–anhydride elastomers, glasses, composites and photopolymers are discussed. Depending on the catalyst strength, 100 % of externally imposed stresses were relaxed in the order of minutes to 2 hours at mild temperatures (80–120 °C). Pristine properties of the original materials were recovered following up to five cycles of a hot‐press reprocessing technique (1 h/100 °C).     

Esters of alternating copolymers of maleic or 2,3-dimethylmaleic anhydride with alkyl vinyl ethers

Maleic anhydride or 2,3-dimethylmaleic anhydride was copolymerized with a number of alkyl vinyl ethers, with AIBN as the initiator. The comonomers were always alternating and were obtained in yields ranging from 15 to 99%. The acid anhydride group in both series of copolymers was converted to the corresponding methyl esters in a two-step reaction. The structure of these polymers was established by elemental analysis and by infrared, ¹H-and ¹³C-NMR spectroscopy. Addtional characterization of these copolymers were carried out by viscosity measurements, differential scanning calorimetry for the determination of glass transition temperatures, and thermal degradation for the determination of the thermal stability of the copolymers.     

马来酸酐接枝聚丙烯的改性方法及其应用

马来酸酐(MAH)是聚丙烯改性中最常用的极性单体,在连续反应中酸酐基呈现很高的活性,反应产物热稳定性良好,可被应用于合金,塑料等材料的生产。随着各种技术的广泛应用,马来酸酐接枝聚丙烯改性方法得到了快速的发展。各种马来酸酐接枝聚丙烯的改性方法有:溶液接枝法、熔融接枝法、固相接枝法和辐射接枝法。文章阐述了马来酸酐接枝聚丙烯改性方法的研究现状及其产物在不同领域的应用。     

Experimental investigation on the mechanical properties of Co-polypropylene/GF/CaCO<Subscript>3</Subscript> hybrid nanocomposites

This study aimed to acquire a balance of mechanical properties comprising impact, tensile and flexural performances in PP based blend. In this respect, co-PP was employed as matrix because of its intrinsic high impact behavior. Hybrid nanocomposites based on co-PP and containing 10 wt % micron-sized short glass fibers (GF) and 2 to 8 wt % nano precipitated CaCO₃ (NPCC) particles were produced by applying a two-step melt compounding method. Maleic anhydride grafted polypropylene (MAPP) was used as compatibilizer. Strong glass fiber-matrix adhesion and relatively uniform distribution of nano-CaCO₃ particles were observed in SEM images. The maximum tensile strength was observed in co-PP hybrid nanocomposite containing 10 wt % glass fiber and 5 wt % nano-CaCO₃ which was 58% more than that of neat co-PP. Flexural strength raised as much as 11% by adding glass fiber. The maximum flexural strength was obtained by incorporating 10 wt % glass fiber and 8 wt % nano-CaCO₃ into co-PP matrix which was 24% higher than that of neat co-PP. The impact strength decreased upon addition of 10 wt % glass fiber and 5 and 8 wt % nano-CaCO₃, this was attributed to the inherent high impact behavior of co-PP as well as strong interfacial interaction between dispersed phases and polymeric matrix.     

Triphenylphosphine-catalysed conversion of maleic anhydride into acrylate esters

Maleic anhydride has been converted into a range of acrylate esters on treatment with a suitable alcohol using triphenylphosphine as a catalyst.     

Increased covalent conjugation of a model antigen to poly(lactic acid)-g-maleic anhydride nanoparticles compared to bare poly(lactic acid) nanoparticles

Maleic anhydride (MA) grafted poly(lactic acid) (PLA) (PLA-g-MA) was synthesized from PLA. Proton nuclear magnetic resonance confirmed the grafting of the MA. PLA-g-MA and PLA were used to prepare polymeric nanoparticles. Particle size distributions were measured by dynamic light scattering, and colloidal stability was determined by (zeta) ζ-potential. The ζ-potential becomes more negative for PLA-g-MA than PLA nanoparticle dispersions, due to the presence of deprotonated carboxylic acid groups on the backbone of the PLA and confirms the MA grafting results. Maleic anhydride grafted on PLA backbone improves the covalent conjugation with ovalbumin (OVA) compared to OVA physically adsorbed on the particles. The chemical conjugation was carried out via amide linkages between the carboxylic groups of the nanoparticles, activated with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and the amino groups of the protein. The amount of protein conjugated was measured by using the bicinchoninic acid method and is threefold higher compared to the adsorbed OVA. Moreover, the PLA-g-MA nanoparticles increased the amount of conjugated OVA by 36 wt% compared to PLA nanoparticles. OVA adsorption and OVA conjugation provided colloidal dispersions with excellent stability.     

A novel technique for preparing of maleic anhydride grafted polyolefins

A novel mechanochemical method of preparation of maleic anhydride grafted polypropylene (MAPP) was developed. The preparation was performed by ball milling of polypropylene (PP) powder, maleic anhydride (MA), and peroxide initiator in balls-containing jars with a planetary ball mill for a certain time. Compared with the conventional melt-mixing method, MAPP obtained through ball-milling technique reveals higher graft degree, particularly alleviated degradation of PP, or even increased molecular mass of the resulting MAPP. Maleic anhydride grafted polyethylene (MAPE) was obtained via this technique, and the optimization of the technique is in progress. The novel technique offers new opportunities in modification of polyolefins, which has also the advantages of solventless, lower process temperature, energy efficient, low cost, and simple running process. Furthermore, it is very easy to obtain purified products.     

乳清蛋白/阿拉伯胶复凝聚法制备载乙酸油酯微胶囊及其表征

油醇(十八烯醇)与乙酸酐的摩尔比为1/1.7,催化剂对甲苯磺酸用量为油醇与乙酸酐总质量的0.2%,25℃反应3h合成了昆虫性激素成分之一的乙酸油酯并对其进行了表征.以高分子电解质乳清蛋白(WP)和阿拉伯胶(GA)进行复凝聚制备聚合物微胶囊,对影响复凝聚的pH、两种电解质的配比及其浓度等因素进行了考察.结果表明在pH=3.5,WP/GA质量比1.5,WP和GA总浓度1.0%时复凝聚效果最佳.在该条件下以WP/GA为壁材对乙酸油酯进行了包覆,制备了不同壁材总浓度的载油微胶囊,对微胶囊的载油量和包覆率进行了测量.随着壁材总浓度的增大,芯材乙酸油酯包覆率呈现先上升后下降的变化趋势.用扫描电镜观察,发现制备的载乙酸油酯微胶囊大小在5～8μm并且乙酸油酯以核壳式结构的形式被包覆在微胶囊内部.     

Correlations between air levels of hexahydrophthalic anhydride (HHPA) and HHPA-adducted albumin tryptic peptides in nasal lavage fluid from experimentally exposed volunteers

Organic acid anhydrides (OAAs) are low molecular weight, reactive compounds extensively used in industry. Exposure to these compounds may lead to allergic symptoms such as rhinitis and asthma. It is important to develop better and more informative methods for assessment of exposure to OAAs. The aim of this study was to develop a method for analysis of specific hexahydrophthalic anhydride (HHPA)-adducted tryptic peptides of human serum albumin (HSA) in nasal lavage (NAL). Furthermore, these peptides were evaluated as biomarkers of exposure. The proteins in the NAL samples were reduced, alkylated and digested with trypsin and the obtained peptides were analyzed using liquid chromatography/tandem mass spectrometry. The total amount of hydrolyzable HHPA in an HHPA-HSA conjugate was used for calibration. A deuterium-labeled HHPA-HSA conjugate was used as internal standard. Five volunteers were exposed to 10, 40 and 80 microg/m3 of HHPA in an exposure chamber and NAL samples were collected before and after exposure. Acceptable precisions of the assay at 13-14% were found for three adducted peptides. The mean levels of these three peptides for the five subjects ranged between 5-22, 15-75 and 33-125 pmol/mL NAL for the exposures at 10, 40 and 80 microg/m3, respectively. High correlations between air levels and the measured peptides were found on an individual basis but there were large inter-individual differences ranging between 63 and 110% for the three peptides. The large differences remained after protein adjustments. It was possible to detect exposures below 10 microg/m3 with the method. Thus, these adducted peptides may be used as biomarkers of exposure, which may better estimate the risk than previous biomarkers developed for OAAs.