氟氯烃-22——丙酮、四氯化碳体系高压汽液平衡的研究

用静态法高压汽液平衡装置测定了氟氯烃-22—丙酮体系在363、15,381,65,399.95K和氟氯烃-22—氯化碳体系在382.98,364.33K下的高压汽液平衡数据,并用SRK,PR,PT和MSRK状态方程对实验数据进行了关联。     

氟氯烃-22—正已烷、环已烷二元系高压汽液平衡数据的测定与关联

<正> 本文采用静态法高压相平衡测定装置测定了氟氯烃-22—正己烷体系在362.95,381.75,400.35K,氟氯烃-22—环己烷体系在363.25,381.95和400.55K的汽液平衡数据,实验装置的详细介绍及操作方法见文献[1～3]。     

氟里昂134a的技术开发

一、背景自从美国卫星探明南极上空出现臭氧层空洞以来,越来越多的证据表明,氯氟烷化食物(CFC),尤其是使用最为广泛的高卤代链烷类化合物如氟里昂11、氟里昂12、氟里昂113等是造成大气臭氧层日益耗竭的重要原因。据资料报道,1985年全世界CFC—11、CFC—12等     

氟里昂在PU泡沫的替代进程

在即将举办的“2004年中国PU泡沫市场与技术交流会”中，有一初定议题是有关氟里昂在PU泡沫行业的替代问题。相关人士对氟里昂的替代问题也有了一个大概的了解。     

氟里昂的替代,回收及转换技术

介绍了国外主要大公司氟里昂替代品的建设与开发情况，同时简要地介绍了氟里昂的回收及以其氟里昂为原料转化为其它无害于环境物质的情况。     

橡胶的耐氟里昂和耐氨性能

引言有些橡胶制品,主要是密封件,在使用中要与氟里昂类物质接触。氟里昂最主要的用途,是作为致冷剂用于制冷设备中。此外,氟里昂还用作气溶胶推进剂、发泡剂、溶剂以及用于化学工业灭火等。     

聚氨酯泡沫塑料用氟里昂的控制（简介）

1987年9月,联合国环境计划署(UNEP)根据“关于破坏臭氧层物质的蒙特利尔议定书”,制定了“控制氟里昂使用法”,并于1989年1月起生效,在日本也正式开始对氟里昂加以限制。本文概述了日本限制氟里昂的动态,并着重介绍削减氟里昂在聚氨酯泡沫塑料中的     

氟里昂的一种新型代用品──二甲醚

氟里昂的一种新型代用品──二甲醚高彦华（武汉硫酸厂研究所，武汉４３００８Ｏ）１前言为了保护人类赖以生存的大气环境，避免大气平流层中的臭氧继续损耗，１９９０年６月伦敦会议修订的蒙特利尔议定书规定，到２０００年要完全停止生产和使用现在广泛使用的氟里昂。世...     

介绍两种生产氟里昂的新工艺

近一二年来我国电冰箱己逐渐进入城市家庭生活中,其发展之迅速实令人惊奇,这种发展趋势方兴未艾。但做为电冰箱的主要冷冻剂氟里昂(其中产量最大、用途最广的品种是甲烷的氟氯化物,其中又以F-12CCl2F2,和F-22 CHC1F2为主)的生产和供应与这种发展形势却很不适应,生产厂家少、规模小、工艺落后、成本高。氟里昂生产工艺落后,成本高,原因是多方面的。主要表现在两个问题上:一是目     

天然沸石应用于氟里昂—12深度干燥通过技术鉴定

天然沸石应用于氟里昂深度干燥是浙江省科委下达的研究课题,浙江省化工研究所在小试的基础上,与临海建新化工厂共同努力,在年产300吨的装置上,通过一年来的运转,完成了研究和工业性生产任务,使氟里昂—12的含水量达到10PPM,超过了省科委下达≤20PPM的质量要求,于85年12月     

Improving the efficiency of gas hydrate crystallization due to the application of gas separation membranes

To improve the efficiency in of the separation and purification of gases by the method of gashydrate crystallization, the possibility of combining it with the membrane method has been studied. A mathematical model has been proposed for the hybrid-membrane gas-hydrate method. The application of membrane methods in gas-hydrate crystallization has been shown to prevent admixtures from concentration in a crystallizer and, thus, to considerably improve the efficiency of the gas separation and purification process. The proposed model of gas separation and purification was used to calculate the ratio of freon-12 purification from nitrogen and oxygen. The application of membrane gas separation with the purpose to prevent an admixture from concentration in a crystallizer was shown to increase the efficiency of freon-12 purification from nitrogen and oxygen via gas-hydrate crystallization by more than an order of magnitude at a high product takeoff (no less than 0.6).     

The volume adsorption capacity of activated carbon for selected trace contaminants

By measuring the time-dependent transmission of a trace contaminant gas through an adsorber bed, we obtained the volume adsorption capacity of (Columbia type 4 LXC 12/28) activated carbon at 25.0°C for four trace contaminants (acetaldehyde, ethanol, acetone and freon-113) each selected to represent an important class of organic compounds (i.e. aldehydes, primary alcohols, ketones and halocarbons). The transmission is the ratio of the concentration at the outlet of the adsorber bed to that at the inlet. Each measurement was carried out at a steady inlet concentration of about 100 ppm in helium at a total pressure of one atmosphere. Adsorption capacities at this low concentration can be determined more readily by this dynamic transmission method than by the conventional static method.     

Synergistic Extraction of Trivalent Actinides and Lanthanides Using Htta and an Aza-Crown Ether

Abstract

An aza-crown ether, 4,13-didecyl-1,7,10,16-tetraoxa-4,13-diazacyclooctadecane (K22DD) has been shown to have a synergistic effect on the extraction of trivalent lanthanides and actinides by thenoyltrifluoroacetone (HTTA). The extraction of Am(III), Cm(III), Am(III), Eu(III), Ce(III), and Pm(III) from an aqueous acetate buffer system (pH=4.8) into HTTA/K22DD/chloroform phase was studied at 25[ddot]C. Distribution coefficients were measured as a function of HTTA concentration, K22DD concentration, and pH user radiotracer techniques. The synergistic species was determined from these studies to be M(TTA)3.K22DD. The results show that the presence of K22DD synergizes the extraction of each of the metals studied by factors of approximately lO⁴-1O⁵. Slightly larger organic phase stability constants were measured for the trivalent actinides relative to the trivalent lanthanides.     

H8Nb22O59·8H2O离子筛制备及其对 钾离子高效分离特性研究*

使用硝酸溶液对高温固相合成的Rb8Nb22O59进行酸洗脱铷离子,制备了离子筛吸附剂H8Nb22O59·8H2O。借助X射线衍射（XRD）、热重分析（TG-DSC）、扫描电镜（SEM）,分别对Rb8Nb22O59和H8Nb22O59·8H2O进行表征。详细考察了吸附剂对钠离子、钾离子的交换性能,筛选出制备吸附剂前驱体Rb8Nb22O59的最优条件,即将五氧化二铌和碳酸铷混合后在1 200 ℃焙烧12 h。研究结果表明：在1 200 ℃焙烧12 h制备的前驱体Rb8Nb22O59与其酸洗后的离子筛H8Nb22O59·8H2O具有相似的结构,前驱体铷离子的酸洗洗脱率可达97%左右,而铌的溶损率极低,小于0.04%,具有很好的再生利用特性;在高浓度氯化钠溶液中（钠与钾物质的量比为500∶1）考察了H8Nb22O59·8H2O对钠离子和钾离子的吸附特性,在pH为2~8内,相对于钠离子,吸附剂H8Nb22O59·8H2O对钾离子具有较高的分配系数,分离因数高达43。焙烧时间6 h以上制备的前驱体Rb8Nb22O59,其酸洗后的离子筛H8Nb22O59·8H2O对钠离子和钾离子的分离因数基本不变。     

CFC混合替代物的汽液平衡研究

自行安装并调试了一套用汽液双循环法测定加压下的汽液平衡数据的实验装置。通过对设备的测温、测压及相平衡测定系统进行调试、校核,表明该装置测定的汽液平衡数据是可靠的。用本实验装置分别测定了HCFC22+HCFC142b二元体系在313.15K、322.80K和328.15K三个温度下的汽液平衡实验数据;HCFC22+HFC152a二元体系在313.15K和328.15K两个温度下的汽液平衡实验数据;HCFC22+HFC152a+HCFC142b三元体系在313.15K、323.15K、328.15K和338.15K四个温度下的汽液平衡实验数据。最后,用Peng-Robinson状态方程对实验数据进行了成功的关联。     

汽油在钾修饰MCM-22分子筛上的烷基化脱硫

在固定床上考察了钾修饰的MCM-22分子筛上模拟催化裂化汽油中的噻吩烷基化脱硫。结果表明,催化剂的强酸有利于噻吩烷基化脱硫反应活性。钾处理显著降低了MCM-22分子筛的强酸数量,对弱酸的影响则相对较小。随着负载钾质量分数的增加,催化剂反应活性显著降低,而噻吩烷基化反应选择性却存在一最佳值,另外,催化剂的稳定性可以得到一定程度改善。     

Identification of Physiological and Toxic Conformations in Aβ42 Aggregates

Aggregation of the 42‐residue amyloid β‐protein (Aβ42) plays a crucial role in the pathogenesis of Alzheimer's disease (AD). Despite numerous structural studies on Aβ aggregates, the relationship between tertiary structure and toxicity remains unclear. Our proline scanning and solid‐state NMR studies suggested that aggregates both of wild‐type Aβ42 and of E22K‐Aβ42 (one of the mutants related to cerebral amyloid angiopathy) contain two conformers: a major one with a turn at positions 25 and 26, and a minor one with a turn at positions 22 and 23. To identify the toxic conformer, the derivative Aβ42‐lactam(22K–23E), in which the side chains at positions 22 and 23 were covalently linked, was synthesized as a minor conformer surrogate, along with Aβ42‐lactam(25K–26E) as a major conformer surrogate. The Aβ42‐lactam(22K–23E) showed stronger aggregation, neurotoxicity, radical generation, and oligomerization than wild‐type Aβ42, whereas in Aβ42‐lactam(25K–26E) were weak. The transition from the physiological conformation with a turn at positions 25 and 26 to the toxic conformation with a turn at positions 22 and 23 might be a key event in the pathogenesis of AD.     

低氰电镀光亮22K金工艺研究

研究了一种低氰电镀光亮22K金工艺。探讨了工艺流程、工艺配方、操作条件、镀液中各组分的影响及镀液的维护。该工艺镀液稳定、分散能力及深镀能力好,镀层光亮,颜色鲜艳,金含量符合22K标准,适合做装饰品镀层。