Recent Progress in Gas Phase Cucurbit[n]uril Chemistry

Cucurbit[n]urils (CB[n]s) are of great significance due to their unique molecular recognition properties and their potential applications in areas such as drug delivery or analytical assays. Gas phase studies, without interference from solvents or counterions, provide fundamental insights into the mechanism of CB[n] complex formation and binding. In this paper, we review the progress in gas phase CB[n] chemistry, mainly based on mass spectrometry, since 2011, including important discoveries in structural studies, mechanistic studies, and gas phase studies related to analytical or clinical applications of CB[n]s. We expect the use of gas phase methods to continue to expand and diversify.     

Pressure Drop and Mass Transfer Study in Static Mixers with Gas Continuous Phase

The aim of this work was to characterize both the influence of the gas and the liquid flow rates on the pressure drop generated by static mixers type Sülzer, and on the mass transfer performances of these gas‐liquid contactors. The originality of this work rests on the use of the static mixers with a gas continuous phase. Several configurations were studied: vertical upward flow, vertical downward flow, and horizontal positions, with one to five mixing elements. It was concluded that the pressure drop is mainly generated by the gas phase, whatever the configuration chosen. Moreover, the volumetric mass transfer coefficients k_La found were lower than those obtained with the same static mixers used in classic conditions (that is with a liquid continuous phase), but greater than values obtained with classic reactors like bubble columns or packed columns. The efficiency of these gas‐liquid reactors was found high, as well as the energy dissipated, unfortunately.     

固相微萃取-气相色谱串联两级质谱法测定水中10种藻类代谢产物

文中建立了固相微萃取-气相色谱串联两级质谱法测定地表水中的10种藻类代谢产物的含量,研究了萃取时间、萃取温度、萃取剂量、萃取纤维等预处理参数对嗅味物质含量的影响,同时对不同规格的色谱柱进行分离效果比较。结果表明,在萃取时间为25 min、萃取温度为65℃、氯化钠含量为1.7 g的测定条件下,采用50/30μm DVB/CAR/PDMS萃取头进行预处理,HP-5MS色谱柱进行分离,质谱检测器进行测定,可以使检测结果达到最优效果。方法的质量浓度均达到5.00～100.00 ng/L,工作曲线回归方程的相关系数R²>0.995;方法检出限(2S/N)为0.14～1.00 ng/L。在纯水加标量为20.00、50.00、80.00 ng/L时,平均回收率为92.0%～109.0%,精密度RSD为0.4%～8.9%,实际水样加标的平均回收率为83.9%～101.8%。该方法检测浓度数量级在纳克级,灵敏度较固相萃取-气相色谱-质谱法提高1 000倍,更适合地表水和饮用水中低浓度藻类代谢产物的检测要求。     

新型旋转填料床的气相传质特性

以CO2-NaOH体系化学吸收测定不同超重力因子、液量和气液比(体积流量比)条件下的有效传质比表面积a,在相同操作条件下,以氨-空气-水体系进行空气吹脱含氨富液测定不同超重力因子、液量和气液比条件下的气相体积传质系数kya,从而得到气相传质系数ky,对其气相传质特性进行了研究. 结果表明,a随超重力因子、液量和气液比增大而增大,kya和ky均随超重力因子和气液比增大而增大,随液量增大而减小. 通过对比可知,在相近操作条件下新型旋转填料床的气相体积传质系数比文献折流旋转填料床的提高36%. 对实验数据进行回归,拟合出a, kya和ky分别与气相雷诺数ReG、液相韦伯数WeL和伽利略数Ga之间的关联式.     

TD-GC/MS法研究气、液相标准物质对环境空气中苯系物含量测定的差异影响

使用热脱附-气相色谱/质谱法(TD-GC/MS),探究了气、液相标准物质对气体样品中苯系物测定的差异影响.分别绘制了7种苯系物气、液相标准物质的校准曲线,发现液相标物中各苯系物的响应明显高于气相标物.通过一系列猜想的提出及穿透实验、二次解析、甲醇试验等的试验验证,认为甲醇大量电离形成的高能量氛围,提高了苯系物的电离能力...     

A Comparative Study of the Thermal Stability and Mechanism of Degradation of Poly(arylene sulphones)

Three poly(arylene sulphones) have been studied by thermogravimetry to ascertain their relative thermal stabilities in both inert and oxidising atmospheres. Experiments have been carried out at a rate of temperature rise of 2°C min^?1 and isothermally at a number of temperatures. The level of stability found compared favourably with that of other heat-resistant materials, for example the addition type polyimides. The polymers have also been examined by pyrolysis gas chromatography mass spectrometry using two different procedures. In the first, fresh samples were pyrolysed at a number of increasing temperatures, whereas in the second, the sample was subjected to successive pyrolyses at the same temperature intervals.     

丁二烯气相聚合过程中聚合物颗粒增长的动态研究

An experimental apparatus composed of microscope, video camera, image-processing, and mini reactor which can be used for real-time measurement of the growth of polymer particle in gas phase polymerization was built up to carry out dynamic study of gas phase polymerization of butadiene by heterogeneous catalyst based on neodymium(Nd). The studies of the shape duplication of polymer particles and catalyst particles and the growth rate of polymer paxticle were made. Results show that the appaxatus and procedure designed can be well utilizedto make dynamic observation and data collection of the growth of polymer particle in gas phase polymerization.A phenomenon of shape duplication of polymer particles and catalyst particles was observed by the real-time measurement. The result also concludes that the activity of individual catalyst particle is different, and the effect of reaction pressure on the growth of polymer particle is significant.     

Influence of phosphine on the diamond growth mechanism: a molecular beam mass spectrometric investigation

We have used a molecular beam mass spectrometer to investigate the effects of addition of phosphine on the growth behaviour of diamond films in a hot filament chemical vapour deposition (CVD) reactor. Films were grown using gas mixtures of 1% CH₄ with increasing amounts of PH₃ (1000–5000 ppm). Gas phase species prevalent during the growth process (e.g. CH₄, CH₃, C₂H₂, PH₃ and HCP) have been monitored quantitatively and compared with the corresponding growth rates, quality and properties of the resulting films. We find that addition of up to 2000 ppm PH₃ increases the film growth rate by a factor of 2–3, and changes the crystal morphology in favour of (100). At higher PH₃ concentrations (3000–5000 ppm) the growth rate decreases again, with predominantly (111) faceted crystals. These observations are discussed in terms of a model of the gas phase chemistry during the growth process.     

2,6-二甲基苯酚气相胺化催化剂的研制

研制了2,6-二甲基苯酚气相胺化合成2,6-二甲基苯胺催化剂Pd/尖晶石，考察了不同γ-Al₂O₃载体和尖晶石的组成对催化剂催化活性的影响，同时研究了反应温度对催化反应的影响。     

A Reaction Flux Model for Extraction of Cu(II) with LIX84I in HFSLM

Hollow fiber supported liquid membrane (HFSLM) is a favorable method to extract both valuable compounds and heavy metal pollutants such as chromium, copper, and nickel at a very low concentration. In this work, the extraction of Cu(II) by LIX84I dissolved in kerosene was theoretically and experimentally investigated. A model to estimate the percentage of extraction of copper ions from synthetic water considering the effect of reaction flux in membrane phase of the HFSLM system was studied. H₂SO₄ solution was used as the stripping solution. The facilitated transport mechanism of the chemical reaction at the feed-membrane interface was taken into account in the model equations. The percentage of copper ion extraction was plotted against its initial concentration in feed and also feed flow rate. Subsequently, the separation time and separation cycle were determined in accordance with the simulated values of copper ion concentration and the feed flow rate from the model. The modeled results were in good agreement with the experimental data at the average percentage of deviation about 2%.     

同位素稀释-气相色谱-三重四级杆串联质谱法测定白酒中的塑化剂含量

以上海化工研究院研制的氘代邻苯二甲酸二甲酯(DMP-D6)和氘代邻苯二甲酸二乙酯(DEP-D10)为内标,利用三重四级杆气相色谱质谱联用仪(GC-MS/MS),建立了白酒中邻苯二甲酸二甲酯(DMP)和邻苯二甲酸二乙酯(DEP)的检测方法。其中,DMP和DEP的检测限分别为0.25和0.1 ng/m L,定量限为0.75和0.375 ng/m L,平均回收率为96.5%和80.0%,精密度均小于5.4%,可满足白酒中DMP、DEP塑化剂的检测需求。     

用多粒模型模拟丁二烯气相聚合的颗粒增长

Gas phase polymerization of butadiene by neodymium catalyst was modeled. The effects of mass and heat transfer resistances in the external boundary layer and within particles, sorption of butadiene in polybutadiene,and deactivation of active sites on polymer particle growth and morphology were studied. Simulation results show that the effects of intraparticle mass and heat transfer resistances on the growth rate of polymer particles are insignificant, and that there is no significant effect of mass transfer resistance on the morphology of polymer particles.The simulation results were compared with the experimental results.     

顶空固相微萃取法用于饮用水源水中环氧氯丙烷的测定

建立了饮用水源水中环氧氯丙烷测定前处理方法—顶空固相微萃取法（HS-SPME）。用75μm Carboxen-PDMS（CAR-PDMS）固相微萃取柱顶空萃取15 mL水样中的环氧氯丙烷,萃取物用GC/MS进行分离和检测,采用MS的选择离子模式和内标法定量。对顶空固相微萃取条件进行了优化,如萃取温度、萃取时间。在优化后的条件下,方法检出限为0.56μg/L,标准曲线的线性相关系数r=0.9994,线性范围为0.25～10.0μg/L;饮用水源水和纯水加标平均回收率介于91.0%～109%（n=6）,对应的RSD为3.67%～11.15%。方法具有简单、环保的特点,适合饮用水源水中环氧氯丙烷的测定。     

与两种气相反应速率系数kc和kp对应的不同活化能

本文讨论了气相反应的kc、kp与其活化能Ea,c和Ea,p之间的关系,及在对行反应中二种活化能与反应热力学能变、焓变之间的关系。通过误差分析论证,我们在教学中提出对Ea,c和Ea,p两种活化能应注意区分。     

丙烯酸固相接枝聚丙烯反应规律性研究

通过正交试验及其单因素实验深入地研究了丙烯酸固相接枝聚丙烯反应的规律,考查了影响固相接枝反应的动力学因素和非动力学因素,并研究了以苯乙烯为共单体的固相接枝反应规律。     

固相萃取-气质联用测定辣椒油中对位红

研究了固相萃取-气质联用测定辣椒油中对位红的分析方法。用Strata-X小柱进行辣椒油样品的前处理,用气质联用法对对位红进行定性和定量分析。对位红方法的检出限为2．0μg／L,平均回收率为93．8％,RSD为1．3～3．5％。