Gas permeation properties of copolyimides from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride and 2,2-bis(3,4-dicarboxyphenyl)hexafluoroisopropane dianhydride

A series of aromatic copolyimides was prepared from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoroisopropane dianhydride (6FDA) with 3,3'-dimethyl-4,4'-methylene dianiline (DMMDA) by a chemical imidization. The gas permeability coefficients of the copolyimides to H-2, CO2, O-2, N-2 and CH4 were measured under 7 atm. pressure. The fractional free volume of 6FDA-DMMDA is larger than that of HQDPA-DMMDA, while the chain segmental mobility of 6FDA-DMMDA is lower than that of HQDPA-DMMDA. The gas permeability of 6FDA-DMMDA is much higher than that of HQDPA-DMMDA but the permselectivity of 6FDA-DMMDA for H-2, CO2, O-2, N-2 over CH4 is lower than that of HQDPA-DMMDA. The experimental values of the gas permeability coefficients of the copolyimides are in satisfactory agreement with the values estimated from the gas permeability coefficients of the constituent homopolyimides and their weight fractions.

Gas separation properties of aromatic polyetherimides from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride and 3,5-diaminobenzic acid or its esters

The gas transport properties of a series polyetherimides, which were prepared from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) with 1,3-phenylenediamine or 3,5-diaminobenzic acid (DBA) or its esters are reported. The effects of carboxylic group (-COOH) and carboxylic ether groups (-COOR), at five positions of 1,3-phenylenediamine moiety, on H-2, CO2, O-2, and N-2 permeability, diffusivity, and solubility of the polyetherimides were investigated. The gas permeability, diffusion, and solubility coefficients of the polyetherimides containing COOR are bigger than those of HQDPA-PDA, but the ideal separation factors and ideal diffusivity selectivity factors are much smaller than that of HQDPA-PDA because COOR decreases chain segmental packing efficiency and increases chain segmental mobility. The permeability coefficients of HQDPA-DBA to H-2, CO2, and O-2 are bigger than those of HQDPA-PDA; the ideal separation factors for gas pairs H-2/N-2, CO2/N-2, and O-2/N-2 are also much bigger than those of HQDPA-PDA. Both the diffusion coefficients of CO2 and O-2 and the ideal diffusivity selectivity factors for CO2/N-2 and O-2/N-2 are bigger than those of HQDPA-PDA because COOH decreases both chain segmental packing efficiency and chain segmental mobility. The copolyimides, which were prepared from 3,5-diaminobenzic acid and 3,5-diaminobenzic esters, have both high permeability and high permselectivity. (C) 1997 John Wiley & Sons, Inc.

1,4-二羟蒽醌红外光谱的振动分析

测量了１，４－二羟基蒽醌及其氘代物的红外光谱，用ＮＲＣＣ程序进行了振动分析。由于同时考虑了分子内与分子间的氢键，统一处理面内与面外振动，计算结果优于文献报道，并纠正了一些错误归属。

高效离心分配色谱仪对异丙基膦酸单(1-己基-4-乙基)-辛酯-稀土萃取体系的研究

首次用高效离心分配色谱仪（ＨＰＣＰＣ）研究用异丙基膦酸单（１－己基－４－已基）辛酯（ＰＴ－２）分离三价重稀土元素，以分离 Ｙｂ（Ⅲ）， Ｅｒ（Ⅲ）及 Ｌｕ（Ⅲ）为例，考察了流动相酸度、流速、固定相浓度、ＨＰＣＰＣ的转速等因素对ＨＰＣＰＣ分离稀土效果的影响，并用ＨＰＣＰＣ法和液－液萃取法研究了ＰＴ－２萃取重稀土的机理。

异丙基膦酸单(1-己基-4-乙基)辛酯萃淋树脂吸萃重稀土元素(Ⅲ)

本文研究了异丙基膦酸单（１－己基－４－乙基）辛酯萃淋树脂在盐酸介质中对重稀土元素（Ⅲ）的吸萃平衡，考察了平衡水相酸度对吸附反应的影响，计算了重稀土（Ⅲ）间的平均分离系数，确定了吸附反应的Ｆｒｅｕｄｌｉｃｈ等温吸附方程。该树脂吸附Ｙｂ（Ⅲ）的静态饱和容量为６６．５ｍｇＹｂ／（ｇ．Ｒ），饱和萃合物的ＩＲ谱表明ＰＴ－２萃淋树脂吸附Ｙｂ（Ⅲ）的反应为阳离子交换反应。

异丙基膦酸单(1-己基-4-乙基)辛酯上胺205-正庚烷乳状液膜分离钪(Ⅲ)、铁(Ⅲ)、镥(Ⅲ)

本文研究了异丙基膦酸单（１－己基－４－乙基）辛酯（简称ＰＴ－２）上胺２０５－正庚烷乳状液膜分离钪（Ⅲ），铁（Ⅲ），镥（Ⅲ）及外相酸度、表面活性剂浓度、流动载体浓度和内相酸度对Ｓｃ（Ⅲ）、Ｆｅ（Ⅲ）、Ｌｕ（Ⅲ）迁移影响。实验结果表明，在一定的条件下Ｓｃ（Ⅲ）有可能实现与Ｆｅ（Ⅲ）、Ｌｕ（Ⅲ）的分离。

1,4-二丙氧基-2,3-二氰基萘的合成

以1，4－萘醌为原料，经溴化、氰化、烷基化合成了1，4－二丙氧基－2，3－二氰基萘，用SiemensP4四圆衍射仪测得了晶体结构。合成方法简便，反应时间短，产率高。

1,4-二丙氧基-2,3二氰基萘的晶体结构

用 Siemens P4四圆衍射仪,测得了1,4-二丙氧基-2,3-二氰基萘的晶体结构。晶体属单斜晶系,空间群为 C2/C。晶格参数 a=14.987(3)A,b=10.527(2),c=11.755(2),β=118.98°(3),晶胞体积 V=1622.4(6)3,Z=4,Dc=1.205Kg/m~3,μ(MoK_α)=0.079mm~(-1),F(000)=624,T=293(2)K_o晶体结构应用直接法,解出最后的偏离因子 R=0.0554[1425个Ⅰ≥2σ(Ⅰ)衍射点]。结构分析表明,萘环的1,4和2,3位碳原子上的氢原子分别被丙氧基和氰基所取代,由于取代基的引入使萘环的结构有所改变。

The crystal structure and drawing-induced polymorphism in poly(aryl ether ketone)s .1. Poly(oxybiphenyl-4-4'-diyloxy-1,4-phenylenecarbonyl-1,3-phenylenecarbonyl-1,4-phenylene)

Crystal structure and polymorphism induced by uniaxial drawing of a poly(aryl ether ketone) [PEDEKmK] prepared from 1,3-bis(4-fluorobenzoyl)benzene and biphenyl-4,4'-diol have been investigated by means of transmission electron microscopy (TEM), electron diffraction (ED), wide-angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC) techniques. The melting and recrystallization process in the temperature range of 250-260 degrees C, far below the next melting temperature (306 degrees C), was identified and found to be responsible for the remarkable changes in lamellar morphology. Based on WAXD and ED patterns, it was found that crystal structure of isotropic-crystalline PEDEKmK obtained under different crystallization conditions (melt-crystallization, cold-crystallization, solvent-induced crystallization, melting-recrystallization, and crystallization from solution) keeps the same mode of packing, i.e., a two-chain orthorhombic unit cell with the dimensions a = 0.784 nm, b = 0.600 nm, and c = 4.745 nm (form I). A second crystal modification (form II) can be induced by uniaxial drawing above the glass transition temperature, and always coexists with form I. This form also possesses an orthorhombic unit cell but with different dimensions, i.e., a = 0.470 nm, b = 1.054 nm, c = 5.064 nm. The 0.32 nm longer c-axis of form II as compared with form I is attributed to an overextended chain conformation due to the expansion of ether and ketone bridge bond angles during uniaxial drawing. The temperature dependence of WAXD patterns for the drawn PEDEKmK suggests that form II can be transformed into the more stable form I by relaxation of overextended chains and relief of internal stress at elevated temperature in absence of external tension.

Structure/permeability and permselectivity relationship of polyetherimides from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride .2.

Gas permeability coefficients of a series of aromatic polyetherimides, which were prepared from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) with various aromatic diamines, to H-2, O-2 and N-2 have been measured under 7 atm and at the temperature range 30-100 degrees C. A significant change in the permeability and permselectivity resulting from the systematic variation in chemical structure of the polyetherimides was found. Among the polyetherimides, that were prepared from phenylenediamine and methyl substituted phenylenediamines, the increase of permeability is accompanied by a decrease of permselectivity. The polyetherimides that were prepared from 3,5-diaminobenzoic esters have lower permselectivity than the others. However, the polyetherimide from 3,5-diaminobenzoic acid possesses much higher permselectivity than the others due to cross-linking. Copyright (C) 1996 Elsevier Science Ltd

Gas permeability in polyimides from oxydianiline and isomeric thiaphthalic dianhydride or 1,4-bis(dicarboxyphenoxy) benzene dianhydride

The gas permeability and permselectivity properties were investigated of polyimides, prepared from 3,3',4,4'- and 2,2',3,3'-thiaphthalic dianhydride (p-TDPA and m-TDPA, respectively), or 1,4-bis(3,4-dicarboxyphenoxy)- and 1,4-bis(2,3-dicarboxyphenoxy) benzene dianhydride (p-HQDPA and m-HQDPA, respectively), and 4,4-oxydianiline. The polyimides prepared from meta-dianhydrides, which have lower chain-segment packing density, possess higher permeability and lower permselectivity than those prepared from para-dianhydrides. Copyright (C) 1996 Elsevier Science Ltd.

Structure/permeability and permselectivity relationship of polyetherimides from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride .1.

Gas permeability coefficients of a series of aromatic polyetherimides, which were prepared from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) and various aromatic diamines, to H-2, CO2, O-2, N-2 and CH4 have been measured under 7 atm pressure and over the temperature range 30-150 degrees C. A significant change in permeability and permselectivity, which resulted from a systematic variation in chemical structure of the polyetherimides, was found. Generally, increases in permeability of the polyetherimides are accompanied by decreases in permselectivity. The order of decrease of the permeability coefficients is as follows: HQDPA-IPDA > HQDPA-DDS > HQDPA-MDA > HQDPA-ODA > HQDPA-DABP > HQDPA-BZD. However, HQDPA-DMoBZD and HQDPA-DMoMDA, with bulky methoxy side-groups on the aromatic rings of the diamine residue, display both high permeability coefficients and high permselectivity. The favourable gas separation property, excellent thermal and chemical stability, and high mechanical strength make HQDPA-DMoBZD and HQDPA-DMoMDA promising candidates for membrane-based gas separation applications.

A new thermoplastic polyimide composite based on 1,4-(3,4-dicarboxyphenoxyl)benzene/4,4'-methylene dianiline

New thermoplastic polyimide (PEI) composites based on 1,4-(3,4-discarboxyphenoxyl)benzene/4,4'- methylene dianiline have been fabricated by the approach of polymerization by the approach of polymerization of monomer reactants (PMR). The chemical and physical behavior of the resin during processing are determined by infrared spectroscopy and rheology. The influence of processing conditions on the composite properties is investigated. The processing, physical and mechanical properties of the composites reinforced with different fibers are presented.

Structure/permeability and permselectivity relationship of polyetherimides from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride .3.

Gas permeability coefficients of a series of aromatic polyetherimides prepared from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) and four (methylene dianiline)s with a methyl side group to H-2, CO2, O-2, N-2, and CH4 were measured under 7 atm and within a temperature range from 30 to 150 degrees C. The gas permeabilities and permselectivities of these polymers were compared with those of the HQDPA-based polyetherimides from methylene dianiline (MDA) and isopropylidene dianiline (IPDA). The number and position of the methyl side groups on the benzene rings of the diamine residues strongly affect the gas permeabilities and permselectivities of the HQDPA-based polyetherimides. The gas permeability of the polyetherimide progressively increases with an increase in the number of the methyl side groups. Both the gas permeability and permselectivity of the polyetherimides with methyl side groups are higher than those of HQDPA-MDA. The polyetherimide prepared from 3,3'-dimethyl 4,4'-methylene dianiline (DMMDA1) possesses both higher permeability and permselectivity than the polyetherimides prepared from 2,2'-dimethyl 4,4'-methylene dianiline (DMMDA2). However, two of the polyetherimides prepared 2,2',3,3'-tetramethyl 4,4'-methylene dianiline (TMMDA1) or 2,2', 5,5'-tetramethyl 4,4'-methylene dianiline (TMMDA2) possess almost the same gas permeability and permselectivity.

DICHLORO(ETA(5)-CYCLOPENTADIENYL)([1-(4-METHOXYPHENYL)CYCLOHEXYL]-ETA(5)-CYCLOPENTADIENYL)TITANIUM(IV)

The title molecule, [TiCl2(C5H5)(C18H21O)], has a pseudotetrahedral bent metallocene structure in which the cyclopentadienyl ring is symmetrically bonded to Ti [range of Ti-C distances 2.36(1)-2.41(1)Angstrom], but the substituted cyclopentadienyl ring adopts asymmetrical bonding [Ti-C 2.33(1)-2.48(1)Angstrom] due to the interaction of the large substituent with the Cl(2) atom. The angle C(11)-C(1)-C(21) is 111.1(8)degrees with the large substituent occupying a cis position with respect to the substituted ring.