Effect of Solvents for the Production of Cyclopentane by Extractive Distillation

In view of the rapid phasing out of fluorocarbons due to their adverse ozone-depleting potential, alternative environment-friendly chemicals are being explored for blowing polyurethane, the key insulation material in refrigeration industries. Cyclopentane with required physical and thermal conductivity properties has emerged as the most appropriate alternative as it can be acquired from light petroleum hydrocarbons, which are abundant. Light naphtha is a mixture of several closely boiling hydrocarbons and hence even a narrow fractional distillation may not enrich cyclopentane for required purity and instead it results only in an azeotropic mixture. This article describes the work carried out in obtaining commercially pure cyclopentane from light naphtha through an extraction-distillation combined operation which is commonly termed as “extractive distillation.” The solvent type and key operating parameters, namely, feed naphtha cut range (heart cut), solvent/feed ratio were studied and the results obtained were further correlated with simulated model prediction.     

环戊烷-四氢呋喃-环己烷三元体系汽液平衡的测定

在常压（101．3kPa）下,用汽液平衡釜测定了环戊烷．四氢呋喃一环己烷三元体系的汽液平衡,所得的汽液平衡数据符合热力学一致性检验,采用改进的UNIFAC方程和Wilson方程对试验数据进行了关联,试验结果与计算结果吻合较好。     

环戊烷进料线三通裂纹原因分析

通过宏观检验、壁厚及硬度测试、化学成分分析和金相检验等方法,对环戊烷进料线三通产生裂纹及补焊后再次开裂的原因进行了分析。结果表明:三通中的裂纹是制造加工时产生的,在安装应力及管系应力的作用下开裂并造成泄漏;补焊后的焊接应力作用于未消除裂纹部位造成了再次开裂。最后对补焊修复和同类型三通检验提出了建议。     

Shape memory effect of poly(methylene‐1,3‐cyclopentane) and its copolymer with polyethylene

Poly(methylene‐1,3‐cyclopentane) (PMCP) cyclopolymerized from 1,5‐hexadiene by metallocene catalyst, rac‐(ethylenebis(1‐indenyl))Zr(N(CH₃)₂)₂ is partially crystalline and has a value of elongation at break of more than 400% in the temperature range 25–85 °C. The shape memory effect of PMCP with moderate molecular weight is enhanced by sequentially polymerized polyethylene segments, the crystalline phase of which seems to strengthen the fixed structure which memorizes the original shape. The glass transition temperature or melting temperature of PMCP can be selectively used as shape recovery temperature when an appropriate deformation temperature is chosen. © 2002 Society of Chemical Industry     

环戊烷萃取精馏脱硫实验动态研究

提出了氢氧化钠溶液作为萃取剂对环戊烷进行萃取精馏脱硫的方法。考察了碱液浓度、剂油比、回流比及助溶剂对脱硫效果的影响。实验结果表明其最佳脱硫条件为:有提馏段,以4%的氢氧化钠溶液作萃取剂,剂油比为4∶3,回流比为1∶5,环戊烷的硫含量最低为0.13mg/L,脱硫率最高可达到97.8%。     

用于环戊烷发泡的组合聚醚的开发

开发了一种能单独用于环戊烷发泡体系的聚醚多元醇ZS-8118,以ZS-8118、匀泡剂、叔胺催化剂、环戊烷、水等原料配制了硬泡组合聚醚。简单讨论了聚醚多元醇品种、匀泡剂及催化剂对发泡体系的影响。结果表明,该组合聚醚贮存稳定性好,制得的泡沫塑料性能优良,能满足冰箱、冷柜等产品的生产要求。     

Speeds of Sound and Isentropic Compressibilities for Binary Mixtures of a Cyclic Diether with a Cyclic Compound at Three Temperatures

Speeds of sound of the binary mixtures of 1,3-dioxolane (or 1,4-dioxane) + cyclopentane (or cyclohexane, or benzene) have been measured at 283.15, 298.15, and 313.15 K. The excess isentropic compressibilities were calculated from experimental data and fitted with a Redlich-Kister polynomial function. Results were analyzed taking into account molecular interactions and structural effects in the mixtures and were compared with literature data. Isentropic compressibilities have been estimated at 298.15 K using the Prigogine-Flory-Patterson theory     

Research on liquid lubricants for space mechanisms

Four research areas at the NASA Glenn Research Center in the United States, involving the tribology of space mechanisms, are highlighted. These areas include: soluble boundary lubrication additives for perfluoropolyether liquid lubricants, a Pennzane® dewetting phenomenon, the effect of non‐ozone depleting chemical bearing cleaning processes on bearing lifetimes, and the development of a new class of liquid lubricants based on silahydrocarbons.     

环戊烷-氢气水合物形成过程研究

利用定容恒温法研究了两种体系(1)氢气-环戊烷-水混合液体系;(2)氢气-环戊烷水合物颗粒体系(两种体系中环戊烷与水的摩尔比均为1:17)在2.0℃、10～18 MPa下环戊烷-氢气水合物的形成特性,比较了两种体系中水合物的形成过程,并计算了储氢量(氢气在水合物中的质量分数)。实验结果表明,在上述条件下,不同体系中环戊烷-氧气水合物的形成速率不同,在氢气-环戊烷水合物颗粒体系中水合物的形成速率相对较快,且在同等条件下储氢量也大,最大储氢量为0.27%。两种体系中形成的环戊烷-氢气水合物的储氢量均随初始压力的升高而增加。最后分析了两种体系中环戊烷-氢气水合物的形成机理。     

Kinetic investigation of CO2 and N2 clathrate hydrate formation using cyclopentane: Application in desalination

Hydrate-based desalination could be a promising technique for producing fresh water from saline water, as it is an eco-friendly process and suitable for large-scale implementation. To make the hydrate-based desalination technology easily scalable, we looked at using air (or N₂) or CO₂ as a hydrate former, along with cyclopentane (CP). Hydrate former CP helps to reduce the operating conditions, as CP forms hydrate at ambient pressure. However, hydrate formation kinetics due to water-insoluble CP is slow. In this work, the kinetics of hydrate formation in saline water were investigated and compared to identify the utility of CO₂ and N₂ as hydrate formers for desalination work. The addition of CP as a hydrate former should transform the structure of CO₂ hydrate from structure I (sI) to structure II (sII), as CP occupies the large cages (5¹²6⁴) in the gas hydrate. A set of three similar reactors were used for this study to collect data quickly. Furthermore, the triple reactor setup is a unique reactor design mounted on a shaker, and a set of SS-316 balls present inside the horizontal reactor imparts the mixing. Experiments with the CO₂-CP mixture and N₂-CP mixture have been studied in the presence or absence of 3 wt.% NaCl at 274 K and 3 MPa pressure. The gas uptake kinetics, water recovery, and separation efficiency have been investigated.