Performance of zeolites and product selectivity in the gas-phase oxidation of 1,2-dichloroethane

The deep oxidation of 1,2-dichloroethane (DCE) over H-type zeolites (H-Y, H-ZSM-5 and H-MOR) was evaluated. Experiments were performed on conditions of lean chlorocarbon concentration (around 1000 ppmv) under dry and humid conditions, between 200 and 550°C in a conventional fixed-bed reactor. The high density of Brønsted acid sites, proved by temperature-programmed desorption (TPD) of ammonia and diffuse reflectance FT-IR of adsorbed pyridine measurements, make H-ZSM-5 zeolite an effective catalyst for DCE decomposition. Vinyl chloride was identified as an intermediate in 250–400°C range. When vinyl chloride was destroyed at higher temperatures, all the zeolites showed a great selectivity (>90%) to HCl. CO was promoted in quantity reflecting the difficulty of its oxidation over these zeolite catalysts. The activity of the zeolites was reduced in the presence of water vapour (15,000 ppmv). It was noticed that the addition of water to the feed stream did not alter the order of activity observed in the dry experiments. Moreover, the presence of water in the DCE decomposition changed significantly the reaction product distribution. Vinyl chloride formation was found to be significantly lowered over the three zeolites, and selectivity to CO₂ formation was largely enhanced. The X-ray powder diffraction (XRD) analysis of the deactivated samples indicated partial destruction of the zeolite crystal structure during reaction.     

Evaluation of H-type zeolites in the destructive oxidation of chlorinated volatile organic compounds

The deep oxidation of 1,2-dichloroethane (DCE) and trichloroethylene (TCE) over H-type zeolites (H-Y and H-ZSM-5) was evaluated. Experiments were performed at conditions of lean hydrocarbon concentration (around 1000 ppmv) in dry air, between 200 and 550°C in a conventional fixed-bed reactor. H-ZSM-5 zeolite resulted more active than H-Y zeolite in the decomposition of both chlorinated volatile organic compounds. It was established that Brønsted acidity plays an important role in controlling the catalytic behaviour of the H-type zeolites. DCE was completely decomposed at 400°C, whereas TCE required higher temperatures (550°C). Vinyl chloride was identified as an intermediate in the DCE oxidation in the range of 250–400°C. When vinyl chloride is destroyed at higher temperatures, both zeolite catalysts show a high selectivity (>90%) towards HCl formation. Trace amounts of tetrachloroethylene were detected in the TCE oxidation, which peaked at 500°C. CO was promoted in quantity in the destruction of both DCE and TCE reflecting the difficulty of carbon monoxide oxidation over H-type zeolites.     

Comparison of Urinary Scents of Two Related Mouse Species, <Emphasis Type="Italic">Mus spicilegus</Emphasis> and <Emphasis Type="Italic">Mus domesticus</Emphasis>

Whereas the house mouse (Mus domesticus) has been studied extensively in terms of physiology/behavior and pheromonal attributes, the evolutionarily related mound-building mouse (Mus spicilegus) has received attention only recently due to its divergent behavioral traits related to olfaction. To date, no chemical studies on urinary volatile compounds have been performed on M. spicilegus. The rationale for our investigations was to determine if there are differences in urinary volatiles of intact and castrated M. spicilegus males and to explore further whether this species could utilize the same or structurally similar pheromones as the male house mouse, M. domesticus. The use of capillary gas chromatography/mass spectrometry (GC-MS) together with sorptive stir bar extraction sampling enabled quantitative comparisons between the intact and castrated M. spicilegus urinary profiles. Additionally, through GC-MS and atomic emission (sulfur-selective) detection, we identified qualitative molecular differences between intact M. spicilegus and M. domesticus. A series of volatile and odoriferous lactones and the presence of coumarin were the unique features of M. spicilegus, as was the notable absence of 2-sec-butyl-4,5-dihydrothiazole (a prominent M. domesticus male pheromone) and other sulfur-containing compounds. Castration of M. spicilegus males eliminated several substances, including δ-hexalactone and γ-octalactone, and substantially decreased additional compounds, suggesting their possible role in chemical communication. Some other M. domesticus pheromone components were also found in M. spicilegus urine. These comparative chemical analyses support the notion of metabolic similarities as well as the uniqueness of some volatiles for M. spicilegus, which may have a distinct physiological function in reproduction and behavior.     

Study of the mineral and phase composition of aluminosilicate refractory ShPD<Subscript>M</Subscript>-45 after service in an aluminum electrolyzer of OAO Zaporozh’e aluminum combine

Comprehensive studies have established that ShPD_M-45 refractory produced by OAO Zaporozhogneupor exhibits good anticorrosion properties towards the action of electrolysis bath corrosive extraneous components. The degree of degradation of ShPD_M-45 refractory after two years of service is 10%. The average concentration of entry of Na_g and F_tot into ShPD_M-45 refractory through hearth blocks with 50% graphite is correspondingly 4.08 × 10^–4 and 3.32 × 10^–4 g-mole/day. It is established that ShPD_M-45 refractory is a more reliable barrier material than unmolded aluminosilicate mixes. The penetration rate of corrosive components of the electrolysis bath into unmolded aluminosilicate materials is greater by a factor of 10 – 30 than for ShPD_M-45 refractory. It is shown that the protective function of titanium-containing components and glass phase in an electrolyzer lining develops as a result of forming fluoride, subfluoride and oxyfluoride titanium compounds. Industrial approval of ShPD_M-45 refractory under OAO Zaporozhe Aluminum Combine conditions has shown that it exhibits good operating properties in electrolyzers with hearth blocks with 50% graphite The authors thank D. V. Pruttskov and D. Yu. Boguslavskii for help with this work. Translated from Novye Ogneupory, No. 3, pp. 45 – 50, March 2009.     

X射线荧光光谱滤纸片法测定有机成分高的土壤中的总磷

传统的方法用磷钼酸比色法测定磷,存在重现性差、栓出限不达标、引入杂质多的问题。现尝试用X射线荧光光谱（XRF）滤纸片法测定有机成分高的土壤中的总磷,分析线强度与元素含量的线性关系好,成本低,测量数据可靠,是一种行之有效的方法。     

歧北凹陷东营组地震地层学分析

应用高分辨率三维地震资料,对黄骅蚴陷中区岐北凹陷东营组进行地震地层学分析,通过该区地震反射终止类型、地震相等的研究,识别三级层序界面,并将东营组划分为四个（SQEd^s。、SQEd^x、SQEd2、SQEd3）三级层序,并总结出歧北凹陷东营组的缓坡破折型和断裂陡坡型两种层序构成样式。     

陈皮浸膏热裂解产物分析及其在卷烟中的应用

运用快速溶剂萃取提取陈皮,浓缩得陈皮浸膏。采用热裂解-气相色谱/质谱联用技术(Py-GC/MS),在300,450,600,750,900℃下分析其热裂解产物,陈皮浸膏在600℃以下裂解产物主要是醛类、酮类、酯类和呋喃类物质;在600℃以上,检测到对人体有害物质,如对二甲苯。卷烟加香实验表明:陈皮浸膏在烟丝中的添加量适宜控制在0.03%~0.05%,药香与烟香协调性较好,刺激性降低。     

生物法处理挥发性有机废气(VOCs)的研究

生物法处理挥发性有机废气是近年来逐步发展起来的一项废气治理新技术,具有效率高、投资及运行费用低、无二次污染、安全性好等优点。文章主要概述了有机废气生物处理的3种主要形式：生物过滤池、生物滴滤塔和生物洗涤器的原理、流程以及研究进展,比较了以上3种反应器的优缺点,并提出了现存问题和将来的研究方向。     

微波辅助乙醇提取刺槐花浸膏及其在烟草中的作用评价

利用微波辅助乙醇提取刺槐花浸膏,研究了提取时间对刺槐花浸膏产率的影响,利用GC／MS分析刺槐花浸膏化学成分,共鉴定出14种成分,并且进行卷烟加香作用评价。结果表明：微波辅助乙醇提取刺槐花浸膏在香气质、香气量、杂气、透发性、浓度、细腻柔和、干燥程度、回甜方面均有所提升,余味有变差的趋势。     

透明塑料组件的注射模设计

通过对某测试台上“仿飞机”＋“翅膀”透明塑料组件的工艺分析,介绍了带活动镶件的注射模结构和设计要点,分析了活动镶件推出抽芯模具的原理,给出了有侧凹的、不能留推出痕迹的透明塑料组件模具的设计方法,解决了不同形状配套使用的多个零件偏心进料引起的受力不均衡的问题,实现了透明塑料组件的顺利生产。