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1.
本文阐述了通过Friedel-Crafts反应合成邻-(4-乙基苯甲酰基)苯甲酸的方法.研究了影响产物质量的因素,提出了适宜的工艺条件. 相似文献
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介绍了使用顶空-气相色谱法检测水中一氯苯的方法。该方法使氯苯分子在气液两相之间、在一定温度下达到了动态平衡。此时,一氯苯在气相中的浓度与它在液相中的浓度成正比。通过测定气相中一氯苯的浓度,即可计算出水样中氯苯的浓度。使用该方法可以直接测定水样,与国标方法相比,它无需琐碎的前处理过程,避免了实验人员与有毒有害溶剂的接触,而且测定结果稳定性较好,能够满足测定需求。 相似文献
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为了得到高纯度的氯苯和二氯苯的同分异构体,本文采用连续侧线出料精馏法从氯苯和二氯苯同分异构体的混合物中分离出氯苯,并为继续分离混合二氯苯提供了基础.本文详细考察了多种因素对连续侧线出料精馏过程的影响,最终确定的最佳操作条件为:进料温度90℃,进料速率2.00ml/min,塔顶采出量0.30ml/min,塔高50 cm(H1=20cm,H2=30 cm).结果表明,在最佳条件下,塔顶氯苯纯度可以达到99.12%,塔顶氯苯得率达到88.12%,塔底二氯苯同分异构体纯度达到97.86%.本文研究结果为进一步提纯二氯苯提供了条件. 相似文献
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介绍了氯化苯生产过程中"三废"的回收利用改造情况,总结了废水、废气、废渣回收改造的过程、特点和效益,经过改造实现了氯苯生产过程的清洁化和废物的资源化。 相似文献
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芳香族化合物的硝化是快速、强放热反应,采用连续硝化工艺可降低间歇操作可能引起的潜在风险。本文采用可视化方法和计算流体力学(CFD)模拟研究微管内流动状况的基础上,在体积为10mL的微管反应器中进行了氯苯连续硝化反应,探究了停留时间、温度、混酸比(硝酸与硫酸的摩尔比)、相比(硝酸与氯苯的摩尔比)对反应转化率、收率、产物邻对比和选择性的影响。结果表明,氯苯和混酸两相在内径为1mm的微通道内呈现出的Taylor流流型可以强化传质传热的效率,提高宏观反应速率。在停留时间为8min、温度80℃、混酸比=1∶1.5、相比=1∶1时,产物中邻对比在0.7~0.8之间,氯苯单程转化率为81.24%,一硝基氯苯的选择性为93.77%。采用连续硝化后,反应停留时间大幅降低,一硝基氯苯的邻对比明显提高。相比于传统釜式工艺,微管反应器内连续硝化更加安全、高效。 相似文献
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Exposure and effects assessment of persistent organohalogen contaminants in arctic wildlife and fish 总被引:1,自引:0,他引:1
Robert J. Letcher Jan Ove Bustnes Christian Sonne Mathilakath M. Vijayan 《The Science of the total environment》2010,408(15):2995-10202
Persistent organic pollutants (POPs) encompass an array of anthropogenic organic and elemental substances and their degradation and metabolic byproducts that have been found in the tissues of exposed animals, especially POPs categorized as organohalogen contaminants (OHCs). OHCs have been of concern in the circumpolar arctic for decades. For example, as a consequence of bioaccumulation and in some cases biomagnification of legacy (e.g., chlorinated PCBs, DDTs and CHLs) and emerging (e.g., brominated flame retardants (BFRs) and in particular polybrominated diphenyl ethers (PBDEs) and perfluorinated compounds (PFCs) including perfluorooctane sulfonate (PFOS) and perfluorooctanic acid (PFOA) found in Arctic biota and humans. Of high concern are the potential biological effects of these contaminants in exposed Arctic wildlife and fish. As concluded in the last review in 2004 for the Arctic Monitoring and Assessment Program (AMAP) on the effects of POPs in Arctic wildlife, prior to 1997, biological effects data were minimal and insufficient at any level of biological organization. The present review summarizes recent studies on biological effects in relation to OHC exposure, and attempts to assess known tissue/body compartment concentration data in the context of possible threshold levels of effects to evaluate the risks. This review concentrates mainly on post-2002, new OHC effects data in Arctic wildlife and fish, and is largely based on recently available effects data for populations of several top trophic level species, including seabirds (e.g., glaucous gull (Larus hyperboreus)), polar bears (Ursus maritimus), polar (Arctic) fox (Vulpes lagopus), and Arctic charr (Salvelinus alpinus), as well as semi-captive studies on sled dogs (Canis familiaris). Regardless, there remains a dearth of data on true contaminant exposure, cause-effect relationships with respect to these contaminant exposures in Arctic wildlife and fish. Indications of exposure effects are largely based on correlations between biomarker endpoints (e.g., biochemical processes related to the immune and endocrine system, pathological changes in tissues and reproduction and development) and tissue residue levels of OHCs (e.g., PCBs, DDTs, CHLs, PBDEs and in a few cases perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonates (PFSAs)). Some exceptions include semi-field studies on comparative contaminant effects of control and exposed cohorts of captive Greenland sled dogs, and performance studies mimicking environmentally relevant PCB concentrations in Arctic charr. Recent tissue concentrations in several arctic marine mammal species and populations exceed a general threshold level of concern of 1 part-per-million (ppm), but a clear evidence of a POP/OHC-related stress in these populations remains to be confirmed. There remains minimal evidence that OHCs are having widespread effects on the health of Arctic organisms, with the possible exception of East Greenland and Svalbard polar bears and Svalbard glaucous gulls. However, the true (if any real) effects of POPs in Arctic wildlife have to be put into the context of other environmental, ecological and physiological stressors (both anthropogenic and natural) that render an overall complex picture. For instance, seasonal changes in food intake and corresponding cycles of fattening and emaciation seen in Arctic animals can modify contaminant tissue distribution and toxicokinetics (contaminant deposition, metabolism and depuration). Also, other factors, including impact of climate change (seasonal ice and temperature changes, and connection to food web changes, nutrition, etc. in exposed biota), disease, species invasion and the connection to disease resistance will impact toxicant exposure. Overall, further research and better understanding of POP/OHC impact on animal performance in Arctic biota are recommended. Regardless, it could be argued that Arctic wildlife and fish at the highest potential risk of POP/OHC exposure and mediated effects are East Greenland, Svalbard and (West and South) Hudson Bay polar bears, Alaskan and Northern Norway killer whales, several species of gulls and other seabirds from the Svalbard area, Northern Norway, East Greenland, the Kara Sea and/or the Canadian central high Arctic, East Greenland ringed seal and a few populations of Arctic charr and Greenland shark. 相似文献