硫代硫酸盐-EDTA-铜离子浸金体系硫代硫酸盐紫外光谱研究

采用紫外光谱对硫代硫酸盐-EDTA-铜离子浸金体系、硫代硫酸盐-氨水-铜离子浸金体系中硫代硫酸盐浓度进行分析和比较。结果表明:在硫代硫酸盐-EDTA-铜离子浸金体系中,无论金是否浸出,硫代硫酸盐浓度呈下降趋势,有金浸出时硫代硫酸盐浓度下降较慢;在硫代硫酸盐-氨水-铜离子浸金体系中,硫代硫酸盐浓度下降较快,其终浓度较硫代硫酸盐-EDTA-铜离子浸金体系中的终浓度要低。     

氘代乙烯制备方法

<正>本发明公开了一种高氘代率氘代乙烯的制备方法,电石与D2O反应生成氘代乙炔,将制备好的氘代乙炔在酸性条件下与D2O反应制得氘代乙醛,氘代乙醛与氘气反应制得氘代乙醇,氘代乙醇经催化脱水制得氘代乙烯。本发明氘代乙烯的制备方法能够用于工业化生产,并在年产300kg工业化实验     

3-和4-氧代-紫罗兰醇糖苷的合成研究进展

3-和4-氧代紫罗兰醇糖苷是一种糖苷类香料前体,用经典的Koenigs-Knorr法,溴代乙酰糖分别与3-氧代-α-紫罗兰醇和4-氧代-β-紫罗兰醇反应可得到3-氧代-α-紫罗兰醇糖苷和4-氧代-β-紫罗兰醇糖苷。详细地说明了3-氧代-α-紫罗兰醇和4-氧代-β-紫罗兰醇的各种合成方法,综述了香料前体3-氧代-α-紫罗兰醇糖苷和4-氧代-β-紫罗兰醇糖苷的合成研究进展。     

3,3,3-三氟-2,2-二甲基丙酸的合成

以自制的2,2-二甲基丙二酸单甲酯为原料,经氟代、水解和酸化反应制备出目标化合物,产率49.6％.分别考察了氟代时间、氟代温度、SF4用量对氟代反应的影响,氟代产物中CH2Cl2含量、水解时间对水解反应进程的影响.适宜的反应条件为:氟代反应时间3h,氟代反应温度80℃,n(2,2-二甲基丙二酸单甲酯)∶n(SF4) =1∶6;氟代产物中CH2Cl2含量≤0.5％;水解反应时间30 min.     

生物柴油的最新研究进展

综述了三代生物柴油的主要特性及发展现状,叙述了第一代生物柴油的生产方法,第二代生物柴油的主要制备工艺及优缺点,介绍了第三代生物柴油的研究现状与发展前景.     

碘代醚类化合物的合成研究

碘代化合物是有机合成化学中的一种重要的中间体.探索了碘代醚类化合物的合成方法.以己二醇为原料,经碘代、成醚,碘化合成了碘代硫醚类化合物,产率达23.5％.以己二醇单碘代中间体为原料,经保护、成醚、脱保护,碘化合成了碘代醚类化合物,产率达30.5％.本合成方法工艺简便、条件温和、原料易得.     

甲烷制卤代甲烷研究进展

甲烷的化学性质很不活泼,需经中间体才能将其转变成高附加值的化工产品。以卤代甲烷为中间体具有能耗低的优势,是一种潜在的甲烷活化方式。综述国内外甲烷制卤代甲烷研究进展,主要介绍不同卤素源条件下的反应机理及催化剂性质、反应条件对单卤代甲烷选择性的影响。甲烷经氯代甲烷活化时,产物中一氯甲烷选择性与催化剂性质密切相关,亲电型催化剂能高选择性生成一氯甲烷;甲烷经溴代甲烷活化时,贵金属和非贵金属均可作为催化剂活性中心,且该反应可以根据后续产物的需要,调节产物组成和比例。甲烷溴代反应单卤代产物选择性高于甲烷氯代反应,但溴代反应需在较高温度进行。     

过渡金属催化氯代物的羰基化反应研究进展

有机氯代物相对于溴代物和碘代物价格低廉且储量丰富，其通过羰基化反应合成的下游产品醛、羧酸、酰胺、酯在大宗化学品、精细化学品以及医药中间体等的生产上有重要应用。本文综合评述了氯代物羰基化反应合成高附加值化学品的重要性,介绍了几种不同类型的氯代物（芳基氯代物、烯丙基氯代物、苄基氯代物、α-氯代酮、1,1-二氯-1-乙烯基化合物、烷基氯代物）羰基化反应（甲酰化反应、酯化反应、酰胺化反应和羧化反应等）在发展新型催化剂体系及高效合成目标产物方面的研究进展,并对该类底物羰基化反应存在的难点以及未来发展方向进行了展望。未来发现更多类型的反应和催化剂体系，实现氯代物的温和羰基化是有机化学研究以及工业化生产的难题及热点。     

氯代苯甲酸的合成研究进展

本文综述了邻氯苯甲酸、间氯苯甲酸、对氯苯甲酸这三种氯代苯甲酸的用途和合成方法。重点阐述了氯代苯甲酸的一系列合成方法,并简要介绍了金属卟啉模拟酶仿生催化氧气氧化氯代甲苯绿色合成氯代苯甲酸的新方法。通过对几种合成方法的比较得知,仿生催化氧化氯代甲苯制备氯代苯甲酸是一种比较有前途的方法。     

壳牌煤气化炉Ⅱ代烧嘴罩的设计特点

简述了壳牌粉煤气化工艺流程,介绍了气化炉烧嘴罩的结构和作用,分析了Ⅰ代烧嘴罩存在的问题及原因;从结构、材质、安装方式等方面阐述了新型Ⅱ代烧嘴罩的设计特点,对比了Ⅱ代烧嘴罩与Ⅰ代烧嘴罩在中石化3套气化装置的应用情况。结果表明,Ⅱ代烧嘴罩的运行较为稳定,较之Ⅰ代烧嘴罩,其泄漏次数之比仅为1∶32。     

Molecular,rheological, and crystalline properties of low‐density polyethylene in blown film extrusion

The molecular weight and its distribution, degree of long chain branching and cooling rate strongly influence crystallinity during processing, which in turn determines the processability and the ultimate properties of the blown film. Generally a decrease in the number of branches and molecular weight of the polymer and the cooling rate results in an increase of the crystallinity. Length of the main chain and extent of branching in low‐density polyethylene (LDPE) are also factors that affect melt rheology and film crystallinity. Long chain branched polyethylene is suitable in the blown film process due to its better melt strength for bubble stability. The objective of this article is to describe the effect of molecular properties (e.g. molecular weight and its distribution, degree of long chain branching etc) of LDPE on film crystallinity at different cooling rates of blown film extrusion. Two different grades of LDPE were selected to investigate molecular characteristics, crystallinity, and rheology. The resins were processed in a blown film extrusion pilot plant using four different cooling rates. Molecular, rheological, and crystalline properties of the resins were key parameters considered in this study. POLYM. ENG. SCI., 47:1983–1991, 2007. © 2007 Society of Plastics Engineers     

三层共挤复合宽幅吹塑棚膜机组的膜泡内冷装置应用效果

简要述及了有吹塑膜泡内冷装置与外冷装置相结合冷却系统的三层共挤复合宽幅吹膜机组的应用。     

LLDPE吹塑地膜力学性能及工艺技术

论述了近年来LLDPE吹塑地膜研究进展情况。重点阐述了选用不同牌号LLDPE混合树脂吹塑地膜能明显提高其力学性能与吹膜工艺性能及生产效率,并介绍了有关工艺技术要点。     

Development of microlayer blown film technology by combining film die and layer multiplication concepts

Many polymers are extruded through blown film dies to produce both monolayer and multilayer films. A common type of die in use today to produce blown films is the spiral mandrel die. This type of die can be used effectively for many polymers in structures containing up to approximately ten layers. This paper will discuss the development of new technology using a feedblock and layer multipliers in combination with encapsulation technology and a unique film die to produce microlayer blown film structures with significantly larger numbers of layers than can be produced using conventional blown film technology. POLYM. ENG. SCI., 56:598–604, 2016. © 2016 Society of Plastics Engineers     

聚乙烯醇改性及吹膜技术研究

研究了聚乙烯醇（PVA）改性及吹膜技术。经改性剂改性前后的IR分析结果表明，改性剂与PVA分子间发生了强烈的相互作用，并形成了较强的分子复合键。改性PVA塑化温度的研究表明，醇解度为88％的PVA，随相对分子质量的增加塑化温度升高。醇解度升高时，PVA塑化性能下降；改性剂用量增加，塑化温度下降。吹膜工艺研究表明，成膜助剂的加入能明显改善改性PVA的加工流动性，PVA膜对冷却效果要求较高，吹膜后的热定型处理能降低其吸湿性，延长水溶时间。     

吹塑薄膜成型工艺建模及仿真研究

在为塑料薄膜吹塑过程建立计算模型的基础上 ,利用有限元软件进行了计算和分析 ,将原用于结构计算的有限元软件引用于吹塑薄膜成型工艺 ,研究并计算了从泡颈到薄膜吹胀成型过程中的膜泡半径和厚度变化 (分布 )。     

FFS袋用吹塑薄膜的生产技术和产品性能

简要介绍了FFS袋用吹塑薄膜产品的用途;重点根据国内外现有装置的生产特点,阐述了生产工艺和产品性能,并对国产吹膜设备和进口设备进行了对比分析,指出了存在的问题和改进方向;简述了投资建设FFS袋用吹塑薄膜装置的经济效益。     

Certain aspects of film blowing of low-density polyethylene

This article considers two topics: (1) Cooling of the film bubble and (2) Production of shrinkable film. Heat is transported by conduction, convection, and radiation, but only convection and radiation are relevant for the cooling results. Heat radiation can be calculated with known surface area, temperatures, and emission coefficient. Here we learn that the emission coefficient depends on the film thickness. Heat transfer by radiation amounts to about 15 percent of the total heat transfer. Heat transfer by convection normally can be calculated by known methods assuming ideal flow conditions. Because the flow conditions of the cooling air differ considerably from ideal conditions, known heat-transfer laws give incorrect results. Therefore, a new formula was set-up by determining the heat transfer conditions in real experiments. Each blown film is shrinkable, but in most cases the influence of the die on the shrinkage is disregarded. The die causes an important anisotropy in the elastic behavior of the film. Further on, shrinkage is influenced by the degree of bubble deformation, the temperature profile, and the deformation velocity between die exit and freeze line. This is discussed qualitatively. A calculations is not yet possible because of the unknown relaxation behavior of the melt. The shrinkage of an LDPE blown film depends on time and temperature. Time and temperature are exchangeable variables.     

Countercurrent cooling of blown film

Presently used methods for the external cooling of blown film involve the use of an air ring located at the base of the bubble that blows air upward along the surface of the bubble. The air is heated as it rises, while the film is cooling and moving in the same direction. This is an example of cocurrent heat exchange, and the result is the accumulation of heated air around the upper portion of the bubble, which interferes with the cooling in this region. While rapid initial cooling is required to maintain bubble stability, we have explored the possibility of using countercurrent cooling for the upper region of the bubble. A standard air ring is mounted at the base of the bubble, and a circular shroud surrounds the bubble above this air ring. All the heated air is collected in an upper chamber surrounding the shroud and is exhausted by means of a secondary blower. The proposed scheme was found to increase heat transfer in the upper regions of the bubble and to permit the ducting of all heated air away from the film line.     

新型软塑材料防静电复合技术研究

通过对导电炭黑填充量对导电性能的探索,优选了集经济性、工艺适性于一体的油炉法炭黑.将油炉法炭黑和聚乙烯树脂混炼造粒,得半导电粒子,经三层(ABC)共挤吹膜工艺和电晕处理技术,制得高表面能防静电聚乙烯薄膜;该薄膜可与其他基材可靠复合成机械物理性能优异的防静电软塑包装复合材料.该产品广泛应用于对静电以及电磁辐射敏感的电子、化工及军工产品的包装,起到良好的静电、电磁和机械物理防护作用.