Effect of methyl groups on the thermal properties of polyesters from methyl substituted 1,4-butanediols and 4,4′-biphenyldicarboxylic acid

Results are reported on the effect of lateral methyl groups on the thermal properties of a series of polyesters prepared from diethyl 4,4′-biphenyldicarboxylate and various methyl substituted 1,4-butanediols. The diols were 1,4-butanediol; 2-methyl-1,4-butanediol; 2,2-dimethyl-1,4-butanediol; 2,3-dimethyl-1,4-butanediol; 2,2,3-trimethyl-1,4-butanediol; and 2,2,3,3-tetramethyl-1,4-butanediol. Apart from the tetramethyl derivatve, the transition temperatures of the methyl substituted polyesters were lower with respect of the unsubstituted polyester. On the basis of polarized photomicrographs, a smectic A mesophase was found for the unsubstituted polyester, whereas a nematic mesophase was observed for the 2-methyl substituted polyster. The 2,2-dimethyl, 2,3-dimethyl, and the 2,2,3-trimethyl substituted polyesters showed no liquid crystalline behavior. The 2,2,3,3-tetramethyl derivative displayed a birefringent melt phase although the DSC measurements were not unambiguous. A copolyester based on diethyl 4,4′-biphenyldicarboxylate, 1,4-butanediol, and 2,2,3,3-tetramethyl-1,4-butanediol showed a broad nematic mesophase. Further evidence for the nematic mesophase of this copolyester and the 2-methyl substituted polyester was provided by dynamic rheological experiments. Based on thermogravimetric analysis, it was concluded that the thermal stability was affected only when four methyl side groups were present in the spacer. © 1995 John Wiley & Sons, Inc.     

Chemical method for removal of impurities impairing the quality of commercial 1,4-butanediol produced by the reppe method

Quantitative dependence of the amount of impurities in commercial 1,4-butanediol that affect the carbonyl number, γ-hydroxybutyraldehyde and its acetate with 1,4-butanediol, on the service life of the catalyst was determined. Hydrazine hydrate, 2,4-dinitrophenylhydrazine, and hydroxylamine hydrochloride were studied as reagents binding these impurities and raising the content of the main substance in the target product. A procedure is suggested for obtaining purified 1,4-butanediol. The optimal reagent is a mixture of a 30% aqueous solution of hydrazine hydrate with hydrochloric acid.     

激光促进乙醇氧化偶联表面反应机理

利用红外光谱（IR）和激光促进表面反应（LSSR）等技术，研究了沉淀法制得Cu2（PO4）（OH）表面上的乙醇氧化偶联合成1，4-丁二醇激光表面反应机理，结果表明：固体表面键激发是激光表面反应的有效激发模式; 乙醇在固体表面材料上的特定化学吸附态形式（－P＝O…H－CH2CH2OH）决定了反应产物的高选择性；固体材料表面晶格氧参与反应是使标题反应能够实现的一个重要因素．     

Oxidation of Tetrahydrofuran and 1,4-Butanediol with Nitric Acid

Preparation of succinic acid by oxidation of tetrahydrofuran and 1,4-butanediol with nitric acid was studied.     

Ripening and growth of zinc oxide nanorods from nanoparticles in 1,4 butanediol solvent

Zinc oxide nanorod formation in 1,4-butanediol was studied as a function of time and temperature using TEM and UV–Vis absorption spectra. Nanorod morphologies are formed by annealing of dilute nanodots, initially formed by sol–gel reaction in 1,4-butanediol. The nanorod morphology is unusual in the termination of the c-axis facets, with one end perpendicular to the a facets (flat) and the other faceted into a six-sided point. Ripening of nanodots proceeds via the Lifshitz–Slyozov–Wagner model of diffusion limited coarsening, and annealing at elevated temperature leads a transition to nanorod morphologies. Nanoparticle dissolution and shape development affect the axial ratio of the growing nanorods. Evidence of oriented attachment was not observed in the ripening study. The use of 1,4-butanediol allows for higher temperature reaction than in alcohols, without the use of pressure vessels.     

Cr-Cu/SiO2催化剂上顺酐和1,4-丁二醇的耦合反应

研究了Cr-Cu/SiO₂催化剂上顺酐加氢反应和1,4-丁二醇脱氢反应耦合制备重要的精细化学品γ-丁内酯. 耦合反应显著提高了顺酐转化率和γ-丁内酯选择性. Cr修饰提高了催化剂的脱氢活性, 抑止了催化剂的过度加氢活性, 使1,4-丁二醇的转化率和γ-丁内酯选择性显著提高. Cr修饰量为w＝5%的Cr-Cu/SiO₂催化剂上耦合反应的原料转化率为100%, γ-丁内酯选择性达98.8%. XRD, XPS等研究表明, Cr修饰促进了催化剂上铜元素的分散, 氧化铬对氧化铜有给电子作用, Cr修饰的Cr-Cu/SiO₂催化剂还原后比Cu/SiO₂具有更多的Cu^＋, 这有利于催化剂脱氢活性和γ-丁内酯选择性的提高.      

Heterochain polyesters Communication 15. Mixed 1,4-butanediol polyesters of two dicarboxylic acids

Summary Ten binary systems of mixed polyesters formed by 1,4-butanediol with two dicarboxylic acids were prepared and investigated.     

The mass spectral fragmentation of 1,4-butanediol

The behaviour of 1,4-butanediol under electron impact at 70 and 12.5 eV has been studied with the aid of high resolution mass spectra. Based on metastable ion decompositions and deuterium labelling, mechanisms are proposed for the formation of the abundant ions of this compound.     

2,3-二羟甲基-2,3-二硝基-1,4-丁二醇四硝酸酯的合成、晶体结构及性能研究

以硝基甲烷为起始原料,经缩合、环化、氧化耦合、脱缩酮及硝化等5步反应合成了2,3-二羟甲基-2,3-二硝基-1,4-丁二醇四硝酸酯(BHDBT),总收率为36.1％,并采用核磁共振谱、红外光谱以及元素分析等进行了结构表征.用浓盐酸代替氯化氢气体,改进了关键中间体2,3-二羟甲基-2,3-二硝基-1,4-丁二醇(BHDB)的合成方法,并确定最佳反应条件为:刀(浓盐酸):n(BDND)=1.1∶1,反应温度55℃,时间4h,收率为94.8％.首次发现了BHDB和BHDBT的亚甲基质子具有磁不等价性,并从理论上分析其产生的原因.培养了BHDBT单晶,四元衍射晶体结构解析表明:BHDBT属于单斜晶系,空间群P2(1)/n,晶胞参数:a=0.81944(11) nm,b=2.3365(3) nm,c=0.85838(11) nm,a=90°,β=113.501(2)°,y=90°,V=1.5072(3) nm3,Z=4,Dc=1.852 g·cm-3,μ=0.189 mm-1,F(000)=856.BHDBT熔点为86.37℃,分解峰温度为185.79℃(DSC),摩擦感度为100％ (3.92 MPa,90°),特性落高H50为10.0 cm(5 kg).     

The Dielectric Properties of 1,4-Butanediol

The dielectric properties of 1,4-butanediol were studied. The static permittivity ε_s was measured at a frequency of 1 MHz. Permittivity ε′ and dielectric loss ε″ were determined by the balance method over the frequency and temperature ranges 2–37.5 GHz and 293–423 K, respectively.     

Investigation of the structure of aqueous solutions of 1,2-and 1,4-butanediol by positron annihilation and ultrasonic methods

The structure of aqueous solutions of 1,2-butanediol and 1,4-butanediol was investigated using adiabatic compressibility measurements and positron annihilation methods. In the case of 1,2-butanediol the experimental results are very similar to those obtained earlier for systems where hydrophobic hydration dominates. In both cases there are evidences for increased rigidity of the water network, which arises from the formation of hydrogen bonds between diols and water. The usefulness of both the methods applied in investigating the structure of liquid solutions was proved.     

CuO/SiO2催化剂上1,4-丁二醇脱氢和顺丁烯二酸二甲酯加氢耦合反应过程

以CuO/SiO₂为催化剂, 在常压固定床反应器上实现了1,4-丁二醇脱氢反应与顺丁烯二酸二甲酯加氢反应的耦合, 制备一种重要的精细化学品γ-丁内酯. 和传统的反应过程相比, 耦合反应提高了顺丁烯二酸二甲酯加氢和1,4-丁二醇脱氢活性. 在优选的反应条件下, 原料的转化率可达100%, γ-丁内酯的选择性可达98%. CuO的最佳负载量为w＝21%附近, 和单层分散阈值计算结果基本符合. XRD与TPR表征结果与单层分散阈值计算结果综合表明: 催化剂的活性组分为高分散的Cu⁰, 负载量过高使得催化剂聚集态铜晶体的比例和粒度都大大增加.     

不同形貌的 CeO2 催化 1,4-丁二醇选择性脱水合成 3-丁烯-1-醇

 以 Ce(NO3)3•6H2O 为铈源, 采用不同沉淀剂制备了 CeO2 催化剂. 运用 N2 吸附-脱附、X 射线衍射、高分辨透射电镜和 H2程序升温还原等技术对催化剂进行了表征, 并评价了其对 1,4-丁二醇选择性脱水合成 3-丁烯-1-醇反应的催化性能. 结果表明, 以不同沉淀剂制得的 CeO2 样品形貌不同, 其中以 Na2CO3 为沉淀剂制备的 CeO2 呈边缘清晰的长方体形貌, 晶粒尺寸较大, 结晶较完整, 优先暴露的 (111) 晶面较多, 在 1,4-丁二醇选择性脱水反应中表现出较高的催化活性和选择性, 3-丁烯-1-醇收率可达 59.7%.     

Liquid crystal polymers. IX. Copolyesters of trans-4,4′-stilbenedicarboxylic acid, 1,4-butanediol,and aromatic dicarboxylic acids

Copolyesters of trans-4,4-stilbenedicarboxylic acid (SDA), terephthalic acid, and 1,4-butanediol exhibit thermotropic liquid crystallinity if at least 40 mol % SDA is present (acids total 100 mol %); SDA/2,6-naphthalenedicarboxylic acid/1,4-butanediol copolyesters are liquid crystalline if at least 30 mol % SDA is present. The effects of SDA content on the thermal, rheological, plastic, and fiber properties of the copolyesters were determined. The SDA component increases the relaxation times of the polymers and enables injection-molded plastics and melt-spun fibers to have significantly increased tensile strength and stiffness.     

Elaboration and characterization of hybrid organic-inorganic gels obtained by reaction of 1,4-butanediol on tetramethoxysilane

New hybrid organic-inorganic gels have been obtained by reaction of 1,4-butanediol, on tetramethoxysilane Si(OMe)₄ dissolved in CCl₄. This reaction does not require water and leads to the formation of polymeric transparent materials.Infrared, ²⁹Si and ¹³C NMR spectroscopy shows that interchange reactions between OMe groups of alkoxide and -O-(CH₂)₄-O of 1,4-butanediol occurred, leading to the monolithic transparent gels in which both organic (Si-O-(CH₂)₄-O-Si) and inorganic (Si-O-Si) bridges are formed.     

Dielectric properties of binary mixtures of three butanediols with 1,4-dioxane and 2-ethyl-1-hexanol at T = 298.2 K

Experimental results of dielectric investigations for solutions of the three butanediols {2,3-butanediol (2,3BD), 1,3-butanediol (1,3BD), and 1,4-butanediol (1,4BD)}, in 1,4-dioxane (1,4DX) are reported for various mole fractions at T = 298.2 K. Values of relative permittivity were measured at 100 kHz. The molecular dipole moments were determined using Guggenheim method. The variations of effective dipole moment and correlation factor, g, with mole fraction in these materials were investigated using Kirkwood–Frohlich equation. Dielectric measurements were also carried out on binary polar mixtures of the butanediols with 2-ethyl-1-hexanol (2EH) for various concentrations at T = 298.2 K. The Kirkwood correlation factor, the Bruggeman factor, and the excess permittivity were determined.     

Synthesis and properties of a monolithic gradient polymer material based on polyurethane structures and 1,4-butanediol as a chain extender

Conditions of preparing monolithic gradient polymeric materials based on aliphatic polyether Laprol 5003 (Voranol 4711), 2,4-tolylene diisocyanate, and 1,4-butanediol as a chain extender have been studied. The materials have been synthesized on a semiautomatic lab molding machine that makes it possible to control the feed rate of precursors; therefore, the chemical structure of the material may be changed in the desired direction. As a consequence, the elastic modulus of the material changes along the sample length from 19 to 410 MPa; that is, the gradual transition from a low-modulus plastic to a rigid rubber occurs. The introduction of 1,4-butanediol improves the viability of precursors and thus hampers the occurrence of premature gelation and creates wide possibilities for obtaining both monolithic and composite reinforced gradient polymeric materials.     

Synthesis and Crystal Structure of 2,3-Bis(dinitrofluoromethyl)-1,4-dioxane

For the first time the dinitromethyl group was modified to dinitrofluoromethyl group in the series of aliphatic polynitro compounds in the case of the reaction of 1,1,4,4-tetranitro-2,3-butanediol diacetate with ammonium fluoroxysulfate in the presence of sodium bicarbonate and ethylene glycol. Previously unknown 2,3-bis(dinitrofluoromethyl)-1,4-dioxane was synthesized. Its structure was determined by X-ray diffraction analysis.     

Cyclodehydration of 1,4-butanediol to tetrahydro- furan catalyzed by supported silicotungstic acid

Summary Acid strength, acid density and the combination ability between silicotungstic acid and support were investigated when supported silicotungstic acid was used as a catalyst for cyclodehydration of 1,4-butanediol to tetrahydrofuran. The interaction between heteropoly acid and support influenced the catalytic activity. TiO2-supported silicotungstic acid catalyst exhibited higher activity than the other catalysts supported on kaolin, kieselguhr, and activated charcoal.     

Cyclodehydration of 1,4-butanediol catalyzed by metal(IV) phosphates

Metal(IV) phosphates of tin, zirconium and titanium in different morphological forms, viz. amorphous, calcined and crystalline, have been used as catalysts for selective cyclodehydration of 1,4-butanediol to tetrahydrofuran. A comparative study of the three catalysts for the above reaction has been carried out to understand the effect of their composition and morphology on the catalytic activity.