Synthesis of aliphatic polyesters containing tetracyanoquinodimethane units by low-temperature polycondensation reactions

The low-temperature solution polycondensation reaction between 1,4-bis-(2′-hydroxy-ethoxy)benzene and adipyl chloride has been studied in N,N-dimethylacetamide. The effect of temperature, concentration, and reaction time on the percent yield and product viscosity has been determined. Optimum conditions were established for the preparation of high molecular weight products and then applied to the synthesis of novel tetracyanoquinodimethane polyesters. Products were characterized by gel permeation chromatography.     

不同涤纶绳索纤维的PY-GC/MS定性分析

利用裂解-气相色谱/质谱联用法对9个不同产地、不同规格的涤纶绳索样品进行鉴别分析.首先通过优化选择,确定试验条件,即裂解温度为550℃、裂解时间为6 s时,柱程序升温条件为50℃(1 min)20℃/min→250℃(10 min).在此条件下可最大限度的显示涤纶裂解产物的特征.9个样品的裂解分析结果显示,涤纶的主要裂解产物有13种,其中特征裂解产物为苯甲酸(相对强度100%)、苯甲酸乙烯酯、联苯、苯等.虽然9个涤纶绳索有相同的裂解特征,但个别裂解产物及各特征裂解产物的相对含量有所不同.这一差异可以作为不同规格、不同产地涤纶绳索分析鉴别的依据.     

蔗糖酯合成新方法的研究

本法以苛性钾与脂肪酸甲（乙）酯首先反应生成的部分中性皂作为乳化分散剂，使蔗糖和脂肪酸甲（乙）酯在熔融状态下直接发生酯交换反应合成蔗糖酯．适宜的反应条件为：蔗糖／硬脂酸甲酯／苛性钾／催化剂的摩尔比１：（１～２）：（０．４～０．６）：０．００３６；１３５～１４０℃、２６６６～６６６５Ｐａ负压下反应３～３．５ｈ。所得粗产物含蔗糖酯５５％，其中单酯６２％。     

界面缩聚法制备间苯二甲酰双酚酸酯聚芳酯

以四丁基氯化铵为相转移催化剂,双酚酸甲酯或双酚酸乙酯与间苯二甲酰氯界面缩聚,合成得到了侧链含酯基的聚芳酯.在吡啶、三乙胺、碳酸氢钠、氢氧化钠中选择合适的催化剂,既可以发生聚合反应又不会使双酚酸酯的酯基发生水解.聚合反应在7种溶剂中进行,通过探讨聚合反应机理以解释溶剂对聚合反应产率以及聚合物特性黏数的影响.以二氯甲烷为溶剂,在优化的聚合条件下较高产率地得到了高特性黏数的聚合物.DSC及TGA分析表明,间苯二甲酰双酚酸酯类聚芳酯具有比间苯二甲酰双酚酸好的热稳定性,热分解温度可从200℃提高到300℃.     

Design and Synthesis of Aromatic Polyesters Bearing Pendant Clickable Maleimide Groups

A bisphenol bearing pendant maleimide group, namely, N‐maleimidoethyl‐3, 3‐bis(4‐hydroxyphenyl)‐1‐isobenzopyrrolidone (PPH‐MA) was synthesized starting from phenolphthalein. Aromatic (co)polyesters bearing pendant maleimide groups were synthesized from PPH‐MA and aromatic diacid chlorides, namely, isophthaloyl chloride (IPC), terephthaloyl chloride (TPC), and 50:50 mol % mixture of IPC and TPC by low temperature solution polycondensation technique. Copolyesters were also synthesized by polycondensation of different molar proportions of PPH‐MA and bisphenol A with IPC. Inherent viscosities and number‐average molecular weights of aromatic (co)polyesters were in the range of 0.52–0.97 dL/g and 20,200–32,800 g/mol, respectively indicating formation of medium to reasonably high‐molecular‐weight polymers. ¹³C NMR spectral analysis of copolyesters revealed the formation of random copolymers. The 10% weight loss temperature of (co)polyesters was found in the range 470–484 °C, indicating their good thermal stability. A selected aromatic polyester bearing pendant maleimide groups was chemically modified via thiol‐maleimide Michael addition reaction with two representative thiol compounds, namely, 4‐chlorothiophenol and 1‐adamantanethiol to yield post‐modified polymers in a quantitative manner. Additionally, it was demonstrated that polyester containing pendant maleimide groups could be used to form insoluble crosslinked gel in the presence of a multifunctional thiol crosslinker. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 630–640     

介孔分子筛Al-MCM-41制备及催化合成二芳基乙烷

以硅酸钠为硅源、硫酸铝为铝源、CTAB为模板剂,采用水热法合成了骨架负载型固体酸Al-MCM-41介孔分子筛催化剂,并通过X射线衍射(XRD)、扫描电子显微镜(SEM)和红外(IR)方法对其进行了表征,同时研究了该催化剂在二芳基乙烷合成反应中的催化性能. 考察了各种反应因素的影响,确定其最佳合成条件为:原料m(苯乙烯)∶m(二甲苯)=1∶7.5,催化剂用量为1%(总投料质量分数),反应时间为3 h,反应温度为140 ℃,产率可达87.1%,比传统催化剂浓硫酸提高了17%. 研究结果表明,该催化剂是替代液体酸合成二芳基乙烷的理想固体酸催化剂.     

生物柴油的催化改性对其冷滤点的影响

利用HZSM-5型分子筛作为催化剂,在250℃～350℃、0.01MPa～0.04MPa的条件下,对生物柴油的主要组分油酸甲酯、棕榈酸甲酯、硬酯酸甲酯、亚油酸甲酯、月桂酸甲酯进行催化改性,以达到降低生物柴油冷滤点（CFPP）的目的。实验研究了反应温度和反应真空度对各脂肪酸甲酯产物的冷滤点、结炭率、碘值的影响,以该实验数据为依据,将动物油经过酯交换制备的生物柴油（AFE）进行催化改性。结果表明,在300℃~350℃,对饱和脂肪酸甲酯改性有很好的降凝效果,产物碘值升高;油酸甲酯通过改性,也取得了很好的降凝效果,产物碘值下降,在该反应条件下改性饱和脂肪酸甲酯和油酸甲酯催化剂的结炭率保持在5%以下;而亚油酸甲酯仅在350℃时改性才有降凝效果,且结炭率在10%以上。生物柴油（AFE）催化改性达到最佳降凝效果的条件为300℃~325℃,0.01MPa,改性后的的酸值小于0.6mg/g,冷滤点下降了19℃,碘值（I.V）为44.32g/100g,运动黏度（μ_t）为4.397mm²/s,并且催化剂结炭率保持在5%以下。     

Protease-catalyzed Synthesis of Bz-Arg-Gly-Asp-OMe in Full Aqueous Medium

Synthesis of N-benzoyl-argininylglycylasparagine methyl ester(Bz-Arg-Gly-Asp-OMe),a precursor tripeptide of Arg-Gly-Asp)was catalyzed by papain under kinetic control,at alkaline pH,in a full aqueous medium.The substrates were N-benzoyl-argininylglycine ethyl ester and asparagine dimethyl ester.An aqueous solution of 0.1 mol/L KCl/NaOH containing 8 mmol/L EDTA and 2 mmol/L DTT was selected as the reaction medium.The synthesized hydrophilic tripeptide was soluble in the reaction medium during the reaction process,however,the secondary hydro-lysis of the tripeptide product was not considerable.The effects of different factors,including water content,temperature,reaction time,and molar ratio of the substrates,on the yield of Bz-Arg-Gly-Asp-OMe were examined.The optimal reaction conditions were 0.05 mol/L Bz-Arg-Gly-OEt and 0.15 mol/L Asp(-OMe)2·HCl in 0.1 mol/L KCl/NaOH solution(pH 8.5),at 40 ℃,and a reaction time of 60 min,with a maximum conversion yield of 62.4%.     

Enzymatic polyesterification in organic media. Enzyme-catalyzed synthesis of linear polyesters. I. Condensation polymerization of linear hydroxyesters. II. Ring-opening polymerization of ϵ-caprolactone

With the object to synthesize polyesters by enzymatic catalysis in organic media, two directions have been investigated: (1) the condensation polymerization of linear ω-hydroxyesters and (2) the ring-opening polymerization of lactones. The commercially-available crude porcine pancreatic lipase (PPL), suspended in organic solvents, was the preferred enzyme for the reactions. In order to determine the optimal conditions for the condensation polymerization, the bifunctional methyl 6-hydroxyhexanoate was used as a model compound to study the influence of the following parameters: type of the enzymecatalyst, kind of solvent, concentration, temperature, duration, size of the reaction mixture, and stirring. Film-forming polyesters with a degree of polymerization (DP) up to about 100 were obtained from linear aliphatic hydroxyesters in n-hexane at reflux temperature (69°C). Yet concurrently with the intermolecular condensation polymerization, macrolactones were also formed by intramolecular reaction. Two aromatic hydroxyesters did not react under these conditions. For the ring-opening polymerization of lactones the reaction of ?-caprolactone with methanol as the preferred nucleophile, was studied. Polyesters with a DP of up to 35 were obtained in n-hexane at temperatures between 25 and 40°C. The degrees of polymerization of the polyesters were determined by comparative analyses of the end groups in the ¹H-NMR spectra and by determination of molecular weights either by vapor phase osmometry, gel permeation chromatography, or intrinsic viscosity. © 1993 John Wiley & Sons, Inc.     

一类可纺丝的全芳香热致性液晶共聚酯的合成和表征

利用Higashi芳香聚酯直接缩聚法的原理 ,采用一步混合投料直接缩聚的方法 ,以对羟基苯甲酸(PHB)、间苯二甲酸 (MPA)、4 ,4′ 二羟基二苯酮 (DHBP)和对苯二酚 (HQ)为单体原料 ,合成了全芳香共聚酯 .该合成方法反应条件温和 ,简单易控 ,产物分子量高 .用差热分析 (DSC)、热重分析 (TA)、偏光显微镜 (PLM)、广角X 射线衍射 (WAXD)等测试分析手段对共聚酯的热性能和液晶特性进行了表征 .研究结果表明 ,利用此方法合成所得的聚合物呈明显的向列型热致液晶特性 ,热稳定性高 ,并具有极易成纤的特点 ,有望成为一种可用于纺丝的全芳香热致液晶共聚酯材料     

辛酸蔗糖酯的超声合成和表征

研究了超声技术促进蔗糖的酯化反应,考察了反应温度、时间、催化剂等对反应的影响．当蔗糖与辛酸乙酯的摩尔比为2：1,反应温度为70℃,催化剂K2CO3占辛酸乙酯质量分数的11％和反应压力为11kPa的条件下,超声反应2h,能高产率地获得辛酸蔗糖酯,且产物的单酯化物含量达92％．产物结构用红外和核磁表征,产物易溶于极性溶剂,热稳定性好,亲水亲油平衡值（HLB）为10．8．     

Synthesis of Polymers by Using Divalent Metal Salts of Mono(hydroxyethyl)phthalate: Metal-Containing Unsaturated Polyesters with Pendent Methacrylate Groups

Syntheses of novel metal-containing unsaturated polyesters having pendent methacrylate groups obtained by use of divalent metal salts of mono(hydroxyethyl)phthalate-maleic anhydride (MA)-glycidyl methacrylate (GMA) reactions were investigated. The yields were generally high. The metal-containing polyesters obtained were slightly yellow-brown solids, and the molecular weights ranged from 1546 to 2174, depending on the mole ratio of feed. Among them, the polyesters obtained at a feed mole ratio of metal salt:MA:GMA of 1:8:8 were miscible with methyl methacrylate (MMA), giving homogeneous solutions suitable for copolymerization, and the polyesters could be easily cross-linked with MMA to give cured resins. The metal-containing cured polyester resins showed excellent physical properties. Resistance of the resins to chemical attack and boiling water and thermal behavior are also discussed.     

聚2,5-呋喃二甲酸1,8-辛二酯的聚合反应

以可再生资源2,5-呋喃二甲酸(FDCA)和1,8-辛二醇(1,8-ODO)为原料,钛酸四丁酯为催化剂,采用直接酯化法制得聚2,5-呋喃二甲酸1,8-辛二酯(1,8-POF)。 考察了原料配比、催化剂用量、酯化温度、缩聚温度及缩聚时间对聚合反应的影响,结果表明,当n(FDCA)∶n(1,8-ODO)=1∶1.2,钛酸四丁酯摩尔分数为0.3%,酯化温度为240 ℃,缩聚温度为260 ℃,缩聚时间为300 min时,缩聚产物的比浓粘度最高（2.1 dL/g）,端羧基含量最低（5.8 mol/t）。 与乙二醇相比,采用1,8-辛二醇为单体降低了酸醇的摩尔比,减少了醇的消耗,同时得到了较高分子量的聚合物。 气质联用仪对酯化馏出液和缩聚产物真空抽出物进行了分析,结果表明,酯化馏出液的主要成分是水,并含有少量的1,8-ODO;缩聚产物真空抽出物的组成为环己酮（56%）、顺式-3-辛烯醇（18%）、4-甲基-3-戊烯-2-酮（17%）和4-羟基-4-甲基-2-戊酮（9%）。     

Chemical kinetic study of the effect of a biofuel additive on jet-A1 combustion

The kinetics of oxidation of kerosene Jet A-1 and a kerosene/rapeseed oil methyl ester (RME) mixture (80/20, mol/mol) (biokerosene) was studied experimentally in a jet-stirred reactor at 10 atm and constant residence time, over the temperature range 740-1200 K, and for variable equivalence ratios (0.5-1.5). Concentration profiles of the reactants, stable intermediates, and final products were obtained by probe sampling followed by on-line and off-line gas chromatography analyses. The oxidation of these fuels in these conditions was modeled using a detailed kinetic reaction mechanism consisting of 2027 reversible reactions and 263 species. The surrogate biokerosene model fuel used here consisted of a mixture of n-hexadecane, n-propylcyclohexane, n-propylbenzene, and n-decane, where the long-chain methyl ester fraction was simply represented by n-hexadecane. The proposed kinetic reaction mechanism used in the modeling yielded a good representation of the kinetics of oxidation of kerosene and biokerosene under jet-stirred reactor conditions and of kerosene in a premixed flame. The data and the model showed the biokerosene (Jet A-1/RME mixture) has a slightly higher reactivity than Jet A-1, whereas no major modification of the product distribution was observed besides the formation of small unsaturated methyl esters produced from RME's oxidation. The model predicts no difference in the ignition delays of kerosene and biokerosene. Using the proposed kinetic scheme, the formation of potential soot precursors was studied with particular attention.     

Biodegradable aliphatic polyesters. Part II. Synthesis and characterization of chain extended poly(butylene succinate-co-butylene adipate)

Poly(butylene succinate-co-butylene adipate) was obtained from 1,4-butanediol and dimethyl esters of succinic and adipic acids through a two step process of transesterification and polycondensation. High molecular weight polyesters were synthesized using hexamethylene diisocyanate as chain extender. The effect of chain extension reaction time and chain extender content on polyester molecular weight, thermal and mechanical properties, was investigated. Polyesters were characterized by means of nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), viscosity measurements, differential scanning calorimetry (DSC), X-ray diffraction (XRD) and mechanical property measurements. Chain extension reaction had as a result the significant increase of polyester molecular weight leading to increased tensile strength. Polyester crystallinity, as calculated from XRD and DSC analysis, and melting temperature decreased upon chain extension, while glass transition temperature increased. Polyester biodegradation was investigated by soil burial and enzymatic hydrolysis using the enzyme Pseudomonas fluorescens cholesterol esterase. It appears that biodegradation was affected by polyester crystallinity, rather than by its molecular weight.     

Synthesis,characterization, and biological evaluation of new polyester containing Schiff base metal complexes

The production of new biocidal polyester Schiff base metal complexes [PESB–M(II)] via polycondensation reaction between chelated Schiff base diol and adipoyl chloride is reported. The resulting polyesters were characterized by physico-chemical and spectroscopic methods. The analytical data of all the synthesized polyesters were found to be in good agreement with 1:1 molar ratio of chelated Schiff base diol to adipoyl chloride. Thermogravimetric analyses of synthesized polyesters were studied by TG in nitrogen atmosphere up to 1073 K and results indicate that Cu(II) polyester complex exhibited better heat resistant properties than the other polyesters complexes. Magnetic moment and UV–visible spectra were examined to explain the structure of all the polyesters which reveled that Mn(II), Co(II), Ni(II) have octahedral geometry while Cu(II) possess a distorted octahedral geometry. These newly developed polyesters were also tested for their antibacterial activity against several bacteria and fungi. Among all the tested compounds PESB–Cu(II) possess the highest bactericidal and fungicidal activity.     

Synthesis of polyester by means of polycondensation of diol ester and dicarboxylic acid ester through ester–ester exchange reaction

Based on our finding that the ester-ester exchange reaction between butyl benzoate and ethyl 4-phenylbenzoate in the presence of a metal alkoxide is faster than the ester-alcohol exchange reaction of butyl benzoate and ethanol, we investigated the synthesis of polyester through ester-ester exchange reaction under various conditions. The polycondensation of diol formate and methyl dicarboxylate in the presence of a catalytic amount of potassium tert-butoxide (^tBuOK) in diglyme at 120 °C under reduced pressure (90–100 Torr) afforded high-molecular-weight polyesters. Methyl dicarboxylate containing an amino group could be used for this polycondensation, although the corresponding diacid chloride containing an amino group was not isolable. The ester-ester exchange reaction could proceed even at the polyester backbone, and the reaction of poly(1,12-dodecamethylene isophthalate) ( PEs ₁ ) with poly(ε-caprolactone) (PCL) in the presence of ^tBuOK at 140 °C afforded a copolymer PEs ₁ -stat-PCL, the structure of which was confirmed by ¹³C NMR spectroscopy and DSC thermal analysis. A similar copolymer was also obtained by the polycondensation of dodecane-1,12-diol formate and dimethyl isophthalate in the presence of PCL and ^tBuOK at 120 °C under reduced pressure.     

Optimisation of Glycerol and Itaconic Anhydride Polycondensation

Glycerol polyesters have recently become objects of interest in tissue engineering. Barely known so far is poly(glycerol itaconate) (PGItc), a biocompatible, biodegradable polyester. Due to the presence of a C=C electron-acceptor moiety, it is possible to post-modify the product by Michael additions to change the properties of PGItc. Thus, using PGItc as one of the elements of cellular scaffold crosslinked in situ for bone tissue regeneration seems to be a very attractive yet unexplored solution. This work aims to optimize the synthesis of PGItc to obtain derivatives with a double bond in the side chain with the highest conversion rates. The experiments were performed with itaconic anhydride and glycerol using mathematical planning of experiments according to the Box-Behnken plan without solvent and catalyst. The input variables of the process were the ratio of the OH/COOH, temperature, and reaction time. The optimised output variables were: the degree of esterification (ED_titr), the degree of esterification calculated from the analysis of ¹H NMR spectra (ED_NMR), and the degree of itaconic anhydride conversion—calculation based on ¹³C NMR spectra (%X_13C^NMR). In each of statistical models, the significance of the changed synthesis parameters was determined. Optimal conditions are when OH/COOH ratio is equal to 1.5, temperature is 140 °C and time of reaction is 5 h. The higher OH/COOH ratio, temperature and longer the experiment time, the higher the value of the degree of esterification and the degree of anhydride conversion.     

Influence of hyperbranched polyesters on the surface tension of polyols

The influence of hyperbranched polyesters with different functional end groups on the surface tension of mixtures with an oligo(ester diol) was investigated. The temperature dependence of the surface tension of the pure components and of the mixtures was measured by a modified Wilhelmy balance technique. The results indicate that the surface tension of the pure hyperbranched polyesters strongly depends on the functionality of the end groups. The functionalization of the hydroxyl end groups by short alkyl chains (methyl, tert-butyl) reduced the surface tension depending on the degree of substitution. The surface tension of the mixtures with the hydroxyl-terminated hyperbranched polyester was slightly increased at higher concentrations of the hyperbranched polymer compared to the surface tension of the pure ester diol. On the other hand, the surface tension of mixtures could be considerably decreased using 1% of hyperbranched polyester polyols partially substituted with short alkyl chains. In that case, the modified hyperbranched polyesters act as surface active agents. On the molecular level, the enrichment of the modified hyperbranched polyester in the surface region was proven by X-ray photoelectron spectroscopy measurements.