毛细管柱气相色谱法测定作业场所空气中1-丁烯和1,3-丁二烯

建立作业场所空气中1-丁烯和1,3-丁二烯的直接进样气相色谱测定方法。利用TEDLAR气袋采集空气样品,以VARIAN–PLOT大口径毛细管柱分离,六通阀进样,FID检测器检测。1-丁烯,1,3-丁二烯的线性范围分别为23.3~466 mg/m3,11.3~225 mg/m3,检出限(3S/N)分别为0.08,0.03 mg/m3,相关系数均大于0.999。测定结果的相对标准偏差为0.8%~3.1%(n=6),回收率在92.0%~104.3%之间。该方法简便、快速、准确,灵敏度高,适用于作业场所空气中1-丁烯和1,3-丁二烯的检测。     

挂式-四氢双环戊二烯热裂解产物分布研究

研究了常压下, 温度为450～650 ℃, 停留时间为15.44～4.03 s条件下的JP-10 (挂式-四氢双环戊二烯)热裂解产物分布. 在相对较长的停留时间下, JP-10热裂解转化率对温度很敏感. 热裂解主要产物为甲烷、乙烯、丙烯、丁烯、丁二烯、环戊二烯、苯、甲苯、苯乙烯、环戊烯的乙烯基取代物及C5, C6异构体(戊二烯、环戊烯的甲基取代物、环己烯、己二烯和环戊二烯甲基取代物), 其中, C1～C4、环戊二烯、苯、甲苯、乙烯基取代环戊烯为初始产物.     

乙烯在ZSM-5催化剂上低聚反应规律的研究

在固定床微反装置上,采用ZSM-5分子筛催化剂,考察了不同条件下乙烯的低聚反应。结果表明,适宜的条件可以抑制副反应,提高产物中丙烯与丁烯的选择性。随反应时间的延长,催化剂因积炭而失活,乙烯转化率由初始的96.2%降至6h后的41.1%,丙烯和丁烯选择性增加。提高乙烯空速可有效抑制氢转移反应从而提高烯烃选择性,根据不同转化率对应的产物分布,得到了ZSM 5催化剂上乙烯低聚的反应路径。乙烯转化率随反应温度的升高先增加后降低,500℃时达到最大值为88.0%,主要产物LPG组分中烷烃居多。提高反应压力有利于低聚反应进行,可以显著提高乙烯转化率,但不利于生成丙烯和丁烯。     

烯烃高效催化剂及聚合与共聚合的研究

为中山大学高分子研究所烯烃配位聚合研究室在高效Ziegler-Natta催化剂、茂金属催化剂烯烃聚合与共聚合方面部分研究工作的概述。重点叙述了催化剂的设计、过渡金属配合物配体结构及聚合条件对乙烯、丙烯、1-丁烯、丁二烯、苯乙烯等烯烃单体聚合及共聚合活性以及聚合产物结构和分子量的影响。     

顶空气相色谱法测定工作场所空气中的乙酸乙酯

采用顶空气相色谱法测定工作场所空气中的乙酸乙酯。气态乙酸乙酯用活性炭管吸附,二氯甲烷解吸,顶空进样,HP–FFAP毛细管柱分离,FID检测器测定,峰面积定量。乙酸乙酯的质量浓度在1.76~880.0μg/m L范围内与色谱峰面积呈良好的线性,相关系数r=0.999 4。不同浓度样品批内测定结果的相对标准偏差为1.34%~3.61%(n=7),批间测定结果的相对标准偏差为1.04%~4.78%(n=7),加标回收率为91.02%~100.29%,方法检出限为0.32μg/m L,解吸效率为91.28%~95.19%。对于100 mg活性炭,乙酸乙酯的穿透容大于2.2 mg,当其浓度在17.6~17 600 mg/m3时,采样效率为91.23%~97.40%,常温下可以保存10 d。该方法各项指标均达到《工作场所空气中有毒物质检测方法研制规范》的要求,适用于工作场所空气中乙酸乙酯的现场监测。     

ZSM-5沸石分子筛增产丙烯表面改性的研究进展

丙烯是极其重要的有机化工原料,其中用于聚丙烯占58%,用于丙烯腈、羰基合成醇、环氧丙烷和异丙苯分别占10%、8%、7%和6%左右.全球丙烯需求年均增长率为5.6%,而2007年之前乙烯需求年均增长率仅为4.6%[1～2].     

SAPO-34晶粒形貌对甲醇转化制低碳烯烃反应的影响

分别采用微波和水热法合成了具有片状及立方结构的SAPO-34分子筛.结果发现,片状SAPO-34分子筛晶粒厚度为130nm,比表面积为593m²/g;立方结构SAPO-34分子筛粒径为1.5-2.5μm,比表面积为708m²/g.二者具有数量相近的强酸中心,后者的弱酸位数量略少.甲醇制烯烃反应结果表明,在450℃和1.0h^-1的反应条件下,片状SAPO-34分子筛的催化寿命可达380min,乙烯选择性最高为51.77%,乙烯、丙烯及丁烯的总选择性最高为90.20%;而立方结构SAPO-34的催化寿命仅为212min,乙烯选择性最高为49.84%,乙烯、丙烯及丁烯的总选择性最高只有86.81%.这可能源于片状晶粒的扩散路径较短,抑制了低碳烯烃的进一步转化及积碳的生成,因此具有较高的低碳烯烃选择性及较长的寿命.     

高效液相色谱法同时测定植物油中4种甾醇烯

建立了高效液相色谱法同时测定植物油中4种甾醇烯的方法。样品用石油醚提取,硅胶柱净化,反相C30柱(250 mm×4.6 mm i.d,5μm)分离,乙腈-叔丁基甲醚(75∶25,V/V)作流动相,等度洗脱,紫外检测(235 nm)。结果表明:4种甾醇烯的质量浓度在0.025～1.0 mg/L范围内;峰面积与质量浓度呈良好的线性关系,线性相关系数r2>0.999。在加标水平为0.050,0.10和0.50 mg/kg时,4种甾醇烯的加标平均回收率为89.2%～109.8%;相对标准偏差RSD<8%;方法检出限(LOD)为0.010 mg/kg。本方法已应用于实际样品分析。     

丁烯催化裂解制丙烯/乙烯反应的热力学研究

 通过对丁烯催化裂解反应网络中各反应步骤进行热力学分析计算,结合实际反应的产物分布,探讨了各产物的形成机理及影响因素. 热力学计算结果表明,升高温度有利于丁烯裂解为丙烯和乙烯,选择合适的反应温度和压力可有效提高产物中的丙烯/乙烯比. 低碳烯烃在热力学上有很强的芳构化倾向,升高温度可抑制氢转移反应,可以通过优化反应条件和开发高选择性催化剂的方法来提高丙烯和乙烯的选择性,抑制芳烃和烷烃的生成. 在催化裂解反应条件下,C5+烃的生成量较少. 热力学计算结果在进行催化剂筛选和反应条件优化过程中得到了验证和补充.     

傅立叶红外光谱法测定丙烯-乙烯共聚物中丙烯单元含量

应用傅立叶红外光谱法,根据丙烯-乙烯共聚物的红外特征性,寻找较好的峰位,使用通用型制膜机制得厚度均匀一致的膜片,制作标准曲线,建立了快速检测丙烯-乙烯共聚物中丙烯单元含量的方法。将红外光谱法分析结果与核磁共振法分析结果进行比较,相对误差在2%以内,测得不同丙烯单元含量的样品的相对标准偏差(n=6)为0.47%~1.1%。     

GC-MS/FID测定环境空气中57种臭氧前体物

建立了GC-MS/FID测定环境空气中57种臭氧前体物的分析方法.优化三级冷阱捕集温度、三级冷阱解析温度、初始柱温、毛细管色谱柱等实验条件.优化条件为:采用硅烷化的苏玛罐采集环境空气,目标组分经三级冷阱在-180℃低温浓缩富集,80℃解析,初始柱温为15℃,结合中心切割技术,将乙烷、乙烯、乙炔、丙烷、丙烯切割至TG-B...     

载体型钛系催化剂的丙烯与乙烯共聚合研究

以载体型钛系齐格勒-纳塔催化剂进行了丙烯和乙烯无规共聚合的研究。对聚合温度、铝钛摩尔比、给电子体浓度和加氢等行为作了考察。共聚合速度和共聚物的比浓粘度呈规律性变化。用~(13)C-NMR和DSC测定了共聚物的组成、序列分布、熔点和结晶度.结果表明,在共聚合反应速度曲线上,在丙烯和乙烯分别为10mol％组成处,出现两个最大值。随共聚物中乙烯含量增加(2—10mol％),其熔点和结晶度降低,DSC峰变低、变宽,在乙烯含量达10mol％处出现双峰(128/116℃)反映出无规共聚链出现不同的序列分布。     

SIMULATION OF EFFECTS OF REACTIVE IMPURITIES ON PROPYLENE POLYMERIZATION IN LOOP REACTORS THROUGH GENERATION FUNCTION TECHNIQUE

The estimation of the amount of reactive impurities in a loop reactor is of strategic importance to the propylene polymerization industry. It is essential to investigate the level of impurities in order to develop reliable monitoring and control strategies. This paper described one approach based on generation function technique with the following two steps. First, a new mechanism for propylene polymerization was proposed by considering the effects of the reactive impurities in the material on the propylene polymerization. Second, a series of equations of population balance for the propylene polymerization in loop reactors were established based on the proposed mechanism. Accordingly, the equations were transformed into the mathematic matrix through the generation function technique to investigate the effects of the reactive impurities on the propylene polymerization. Significant effects of the reactive impurities were analyzed through computational simulation. The results show that the concentration of active centre on catalysts and the polymerization conversion both decrease with the increase of the initial concentration of any reactive impurity; hydrogen concentration decreases with the increase of the initial concentration of ethylene or butylenes, whereas, it increases with the increase of the initial concentration of propadiene; the simulated weight average molecular weight and the molecular weight distribution index of polymer resins both increase with the increase of the initial concentration of ethylene or butylenes. They decrease with the increase of the initial concentration of propadiene.     

SAPO-34分子筛催化丁烯转化制丙烯的研究

通过水热法合成SAPO-34分子筛,将其制成催化剂用于催化丁烯转化制取丙烯,考察了反应温度、空速和铝磷比等对催化性能的影响;还比较了SAPO-34分子筛与ZSM-5分子筛催化该反应的差异.结果表明,在实验范围内,反应温度升高会使得丁烯的转化率明显增高,且丙烯选择性提高;而空速增加,则丁烯的转化率和丙烯选择性降低;铝磷比越大,对丙烯的选择性越差.在有效的反应时间内,SAPO-34分子筛催化效果好于ZSM-5分子筛,但单程寿命较ZSM-5分子筛短.     

Copolymerization of propylene with 1,3‐butadiene using isospecific zirconocene catalysts

Poly(propylene‐ran‐1,3‐butadiene) was synthesized using isospecific zirconocene catalysts and converted to telechelic isotactic polypropylene by metathesis degradation with ethylene. The copolymers obtained with isospecific C₂‐symmetric zirconocene catalysts activated with modified methylaluminoxane (MMAO) had 1,4‐inserted butadiene units ( 1,4‐BD ) and 1,2‐inserted units ( 1,2‐BD ) in the isotactic polypropylene chain. The selectivity of butadiene towards 1,4‐BD incorporation was high up to 95% using rac‐dimethylsilylbis(1‐indenyl)zirconium dichloride (Cat‐A)/MMAO. The molar ratio of propylene to butadiene in the feed regulated the number‐average molecular weight (M_n) and the butadiene contents of the polymer produced. Metathesis degradations of the copolymer with ethylene were conducted with a WCI₆/SnMe₄/propyl acetate catalyst system. The ¹H NMR spectra before and after the degradation indicated that the polymers degraded by ethylene had vinyl groups at both chain ends in high selectivity. The analysis of the chain scission products clarified the chain end structures of the poly(propylene‐ran‐1,3‐butadiene). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5731–5740, 2007     

Using Design of Experiments to Optimize a Screening Analytical Methodology Based on Solid-Phase Microextraction/Gas Chromatography for the Determination of Volatile Methylsiloxanes in Water

Volatile methylsiloxanes (VMSs) constitute a group of compounds used in a great variety of products, particularly personal care products. Due to their massive use, they are continually discharged into wastewater treatment plants and are increasingly being detected in wastewater and in the environment at low concentrations. The aim of this work was to develop and validate a fast and reliable methodology to screen seven VMSs in water samples, by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography with flame ionization detection (GC-FID). The influence of several factors affecting the extraction efficiency was investigated using a design of experiments approach. The main factors were selected (fiber type, sample volume, ionic strength, extraction and desorption time, extraction and desorption temperature) and optimized, employing a central composite design. The optimal conditions were: 65 µm PDMS/Divinylbenzene fiber, 10 mL sample, 19.5% NaCl, 39 min extraction time, 10 min desorption time, and 33 °C and 240 °C as extraction and desorption temperature, respectively. The methodology was successfully validated, showing low detection limits (up to 24 ng/L), good precision (relative standard deviations below 15%), and accuracy ranging from 62% to 104% in wastewater, tap, and river water samples.     

Determination of Teucrium chamaedrys volatiles by using direct thermal desorption-comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry

The direct qualification and quantification of the volatile components of Teucrium chamaedrys was studied using a direct thermal desorption (DTD) technique with comprehensive two-dimensional (2D) gas chromatography-time-of-flight mass spectrometry (GC x GC-TOF/MS). The GC x GC separation chromatographically resolved hundreds of components within this sample, and with the separation coupled with TOF/MS for detection, high probability identifications were made for 68 compounds. The quantitative results were determined through the use of internal standards and the desorption of differing amounts of raw material in the injector. The highest yield of volatile compounds (0.39%, w/w) was obtained at 150 degrees C thermal desorption temperature using 1.0mg of dried sample placed in a glass injector liner when studied over the range 1.0-7.0mg. Lowest yield of 0.33% (w/w) was found for the largest sample size of 7.0mg. Relative standard deviation (RSD) for 10 replicates at each size sample were in the range 3.9-21.6%. The major compounds identified were beta-pinene, germacrene D, alpha-pinene, alpha-farnesene, alpha-gurjunene, gamma-elemene and gamma-cadinene. All identified compounds were quantified using total ion chromatogram (TIC) peak areas. DTD is a promising method for quantitative analysis of complex mixtures, and in particular for quantitative analysis of plant samples, which can yield data without the traditional obligation for costly and time-consuming extraction techniques.     

以氯代钒酸酯-三异丁基铝催化体系合成丁二烯-丙烯交替共聚物的研究

本文比较了各种氯代钒酸酯-三异丁基铝体系催化丁二烯、丙烯交替共聚的活性,得出氯代钒酸二新戊酯-三异丁基铝体系催化活性最高。能制得高分子量的交替共聚物。研究了该催化体系的特点和聚合规律及提高共聚物[η]的途径。在-76--45℃温度范围内可以制得正[η]为1.7-2.6dl/g的丁丙交替共聚物,单体转化率在80％以上。通过分析鉴定,证明产物交替度在95％左右,反式1,4丁二烯组分含量在95％以上。     

Significant Breakthrough in Industrial Test of the "Methanol to Olefins" Process Developed by Dalian Institute of Chemical Physics, Chinese Academy of Sciences

A process of "Methanol or Dimethylether to Olefins" developed by Dalian Institute of Chemical Physics (DICP), designated as the DMTO process, has attained great success in industrial scaling up testing. DICP, by collaborating with the Xinxing Coal Chemical Co., Ltd. of Shaanxi Province and the Luoyang Petrochemical Engineering Co. of the SINOPEC Group, operated successfully a 50t(methanol)/d unit for the conversion of methanol to lower olefins, with a methanol conversion of close to 100%, and a selectivity to lower olefins(ethylene, propylene and butylenes) of higher than 90%. On 23rd August, the industrial test project has passed a state appraisal. The experts of the Appraisal Group, headed by Prof.     

二阶梯度升温热解吸法测定空气中的微量丙烯腈和乙腈

采用气体采样泵将空气样品的丙烯腈和乙腈吸附到吸附管中,用二阶梯度升温将吸附管中的被测物质解吸到冷阱中,再快速对冷阱升温,将冷阱中的被测物质解吸进入色谱柱进行分离,用气相色谱氢火焰检测器检测空气中的微量丙烯腈和乙腈。丙烯腈、乙腈的色谱峰面积与吸附质量的线性相关系数均大于0.995。该法对实际空气样品中丙烯腈的检出限为5μg/m3,乙腈的检出限为10μg/m3,加标回收率均大于90%。