关于乙苯的论文外文文献

【中文名称】1，4-二甲苯，对二甲苯【英文名称】 para-xylene，1，4-dimethylbenzene对二甲苯【结构或分子式】 C8H10；C6H4(CH3)2【分子量】 106.17【蒸汽压】 1.16kPa/25℃【闪点（℃）】25 ℃（封闭式），27.2 ℃（开放式）【熔点（℃）】13.2【沸点（℃）】138.5【溶解情况】不溶于水，可混溶于乙醇、乙醚、氯仿等多数有机溶剂【密 度】 相对密度（20/4℃水）0.8611，（25/4℃水）0.8610；相对密度（空气=1）3.66【稳定性】 不稳定【折射率】（nD25）1.4958，（nD21）1.5004[1]【毒性】低毒化合物，毒性略高于乙醇【可燃性及爆炸性】可燃，其蒸气与空气可形成爆炸性混合物，爆炸极限1.1%～7.0%化学性质折叠编辑本段1、对金属无腐蚀性，用稀硝酸氧化生成对甲基苯甲酸，继续氧化生成对苯二甲酸。与其他氧化剂的作用和邻二甲苯类似。对二甲苯在碳酸钠水溶液和空气存在下，于250℃，6 MPa下生成对甲基苯甲酸、对苯二甲酸、乙醛。用钴盐作催化剂，120℃经空气液相氧化生成对甲基苯甲酸。氯化反应与其他二甲苯类似。对二甲苯热解生成甲烷、氢、甲苯、对联甲苯、2，6-二甲基蒽。2、稳定性：稳定3、禁配物：强氧化剂、酸类、卤素等4、聚合危害：不聚合[2]5、常见化学反应：甲基能被常见氧化剂氧化。如用稀硝酸氧化生成对甲基苯甲酸，继续氧化生成对苯二甲酸；用酸性高锰酸钾也能将甲基氧化成羧基。甲基上的氢原子能被卤素取代。主要用途用于生产对苯二甲酸，进而生产对苯二甲酸乙二醇酯、丁二醇酯等聚酯树脂。聚酯树脂是生产涤纶纤维、聚酯薄片，聚酯中空容器的原料。涤纶纤维是我国当下第一大合成纤维。也用作涂料、染料和农药等的原料。对急救人员之防护：折叠⒈戴防护衣服（包含防溶剂手套）以免接触污染物。⒉戴化学护目镜。对医师之提示：对于食入者考虑洗胃及活性碳浆。相关标准：折叠人体危险上限：900 ppm（3.9 g/m）国外常见标准（推荐）：长期暴露上限（以一天工作八小时）：100 ppm （435 mg/m），短暂暴露上限150 ppm（655 mg/m）二甲苯的代谢物甲基马尿酸被认为是监测二甲苯浓度的指标。美国政府工业卫生学家会议建议将尿液中甲基马尿酸浓度上限设定为2克/升。[6]中国国内标准比国外低。危险标记折叠根据《全球化学品统一分类和标签制度》和《危险化学品名录》，在包括美国澳大利亚在内的很多国家，PX属于危险化学品，PX同时属于有害品，是因为当人体吸入过量PX时，对眼及上呼吸道有刺激作用并会出现急性中毒。无论是危险标记、健康危害性、毒理学资料，还是在职业灾害防护等标准下，PX都不属高危高毒产品。长期反复直接接触PX会使皮肤脱脂，并有可能对中枢神经系统或听力有影响，也可能对人类生殖或发育造成毒性。安全性折叠对二甲苯的液体及蒸汽易燃。进入消化道可导致中枢神经系统抑制，症状包括兴奋，随后头痛、眩晕、困倦和恶心，严重者导致失去知觉、昏迷，并由于呼吸中断而致死。可能造成肝、肾损伤。吸入时可能造成呼吸困难等和吞入类似的后果，及化学性肺炎和肺水肿、黏膜损伤、血液异常。二甲苯蒸汽对眼部及上呼吸道有刺激，高浓度时会麻醉中枢神经。短期吸入高浓度对二甲苯会出现明显的刺激症状、眼结膜及咽充血、头晕、头痛、恶心呕吐、胸闷四肢无力、意识模糊、步态蹒跚。重者甚至会躁动、抽搐或昏迷。 长时间或重复性接触或吸入以及短期吸入高浓度对二甲苯使皮肤脱脂，可造成皮肤干裂或刺激及产生神经衰弱综合征（如呼吸困难、混乱、眩晕、恐惧、失忆、头痛、颤抖、虚弱、厌食、恶心、耳鸣、暴躁、口渴、肝功能减弱、肾损伤、贫血症、骨髓的增生等）损害。此物质曾造成动物的繁殖损害和致命性结果。制备方法折叠编辑本段对二甲苯（PX）是一种重要的有机化工原料，主要用于生产精对苯二甲酸（PTA），进而生产聚酯。由于我国聚酯、PTA产业链的大规模发展，形成了对原料PX的巨大需求。如今，PX的工业生产方法主要有歧化及烷基转移、二甲苯异构化、二甲苯吸附分离和二甲苯分离等方法：歧化及烷基转移工艺技术折叠甲苯与C9芳烃在分子筛催化剂作用下选择性转化成苯和二甲苯。ARCO公司20世纪60年代开发出Xylene-Plus技术，该技术为非临氢转化技术，但其操作费用较高、催化剂性能不好、转化率低、选择性较差。1969年进入工业化的Tatoray技术，采用绝热固定床反应器，丝光沸石催化剂，临氢操作，反应原料为甲苯和C9芳烃。该工艺具有反应器结构及反应流程简单、转化率高、选择性高等特点，而且该工艺不仅可以处理甲苯，还可以充分利用C9芳烃，最大限度地满足生产PX的要求。此外还有于1988年实现工业化的甲苯选择性技术（MSTDP）。[7]二甲苯异构化工业技术折叠二甲苯异构化工艺技术是以基本不含或含少量PX的混合C8芳烃为原料，在催化剂作用下C8芳烃4种异构体（OX、MX、PX和乙苯）之间的转化技术。反应使混合C8芳烃中的PX浓度达到平衡浓度，从而提高PX产量。目前国内已引进几套二甲苯异构化装置，都以生产PX（或同时副产OX）为主要目的。我国已引进的二甲苯异构化技术均为贵金属催化剂的临氢异构化技术，该法采用有限的C8芳烃资源，能够获得比其他类型异构化工艺更多的PX及OX。[7]吸附分离工艺技术折叠吸附分离工艺技术是从混合C8芳烃4种异构体（OX、MX、PX 及乙苯）中分离出PX。由于C8芳烃4种异构体化学结构相似，其物理性质尤其是沸点也接近，这给C8芳烃的分离带来困难，用通常的精密蒸馏法难以实现。专门用于二甲苯分离的工业化方法有传统的深冷结晶和选择性吸附法两种，选择性吸附方法是采用特定分子筛吸附剂和模拟移动床吸附塔对C8芳烃中的PX进行选择性吸附，再用解吸剂将PX从吸附剂上解吸下来，达到从C8芳烃中分离出PX的目的。选择吸附法在建设费用、操作费用、原料和公用工程消耗指标以及产品质量等方面均明显优于深冷结晶法。翻译：Chinese [name] 1, 4- dimethyl benzene, p-xyleneEnglish [name] para-xylene 4-dimethylbenzene, 1, para xyleneThe molecular formula C8H10 [or]; C6H4 (CH3) 2The molecular weight of 106.17 [][C] the vapor pressure of 1.16kPa/25Flash point (c)] [25 C (closed), 27.2 degrees (open)The melting point (13.2 C) [][(c)] 138.5 boiling point[solution] is not soluble in water, but miscible in ethanol, ethyl ether, chloroform and most organic solventsThe density of the relative density ([] 20/4 C 0.8611 (water), the temperature of 25/4 DEG C water)0.8610; relative density (air =1) 3.66The stability of unstable [][index] (nD25) 1.4958, (nD21) 1.5004[1][] low toxicity compounds, the toxicity is slightly higher than that of ethanolFlammable and explosive [] combustible, its vapor and air can form explosive mixtures, explosion limit of 1.1% to 7%The chemical properties of the folding editor this paragraph1, non corrosive to metal, formic acid methyl benzene with dilute nitric acid oxidation to terephthalic acid, oxidation. And other similar to the effect of oxidant and o-xylene. Para xylene in the presence of sodium carbonate solution and air, at the temperature of 250 MPa, 6 generation of methyl benzoic acid, terephthalic acid, acetaldehyde. Cobalt salt as catalyst at a temperature of 120 DEG C, by liquid phase air oxidation of methyl benzoate. Chlorination reaction similar to other xylene. P-xylene methane, hydrogen, toluene, poetic couplet of toluene, 2 6-, two methyl anthracene.2, the stability: stable3, cut material: strong oxidizing agents, acids, halogens etc.4, hazardous polymerization: polymerization of [2]5, common chemical reaction: methyl can be common oxidant. Such as formic acid methyl benzeneformation with dilute nitric acid oxidation to terephthalic acid, oxidation; acid Potassium Permanganate can also be oxidized to carboxyl methyl. Methyl hydrogen atoms can be replaced by halogen. The main purpose ofFor the production of terephthalic acid, then the production of polyethylene glycol terephthalatepolybutylene terephthalate resin, etc.. Polyester resin is the production of polyester fiber, polyester film, polyester hollow container material. Polyester fiber is the first synthetic fiber. Also used as coating materials, dyes and pesticides etc..Edit this paragraph of toxicological data foldingAbsorption of foldingThe experiment showed that the rats and mice, xylene in high lipid content in tissue deposition,such as: fat, vascular, brain and blood vessel dense organs such as kidney and liver. O, p-xylenecan cross the placenta, amniotic fluid and neonatal tissue distribution. Rat oral carbon 14 labeled o-xylene, m-xylene in adipose tissue distribution, accumulation of 0.3% (female), 0.1% (male).Autoradiography shows, in male rats after inhalation of p-xylene in the nasal mucosa and theolfactory bulb appeared metabolites accumulation. The metabolites may be aromatic acids (such as: methyl hippuric acid and benzoic acid). The same experiment was performed in the pregnantmice, found that after exposure to 2000 ppm, xylene in the brain and lung density is higher, while the concentration in kidney and liver is relatively low.The skin and respiratory tract is the way the human body to absorb xylene. Exposure to 46 or 92 ppm (parts per million), xylene or neighbor, xylene and other mixtures of 8 hours, inhaled xylene64% would be absorbed by the body. Because of the respiration rate (breaths per minute), xyleneabsorption differ from man to man. The larger the respiration rate, the fewer xylene holdback. 20 ppm xylene by respiratory absorption rate was 57.7%. The experimental data of m-xylene, in 100ppm exposed to 5-10 minutes, the absorption rate of 60%, and to reach the equilibrium state.For men aged 20-35 experiment (experiment condition: the concentration of 600 ppm, temperature25 degrees, relative humidity 50%, 3.5 hour long show), xylene vapor can be absorbed through the skin. Dermal exposure test (dermal exposure) was 6 nmol / cm2 / h, while the liquid xylene through the skin and the speed is 1.13 mol / cm2 / hour. Percutaneous absorption of xylene with methylhippuric acid excretion time longer than 2-4 hours after inhalation of xylene. [2]To fold the impact of pregnancyIn the eleventh pregnancy, 14, 17 days of exposure, were detected in 2000 ppm pregnant mousexylene were detected in 10 minutes, after the exposure of 0, 0.5, 1 and 4 hours. Results show that the p-xylene can quickly enter into embryo, but relative to the amount of mature tissue matrix issmall. During the period of pregnancy in mice (11, 14, 17 days), p-xylene can be quickly through the placenta, but the concentration in the fetus is low; 2% will be distributed in rats brain of p-xylene. On day 11 of gestation, the average distribution of xylene in embryo; on day 17 of gestation, xylene in embryo mainly stay in the liver.ExcretionMost in vivo xylene quickly by the body metabolism and is excreted in urine. The experiments show that, oral, each 1.8 grams of o xylene, in 24 hours, 50% of xylene in urine was excreted. #Inhaled xylene to form 95% metabolites excreted in the urine, generally metabolites of xylene ismethyl hippuric acid; the remaining 5% will be out. Only less than 0.005% of xylene in the form ofxylene is excreted in the urine, less than 2% to two methyl phenol removal. Methyl hippuric acidexcretion is very quickly, after two hours of exposure to benzene, methyl hippuric acid will discharge a lot, and the upward trend. [4]Distribution in vivo foldingShows that the adult rats, after exposure to 217 mg / m3 (50 ppm) after 8 hours of xylene, mark

苯与乙烯烷基化反应制备乙苯在石油工业上有广泛的应用,乙苯是生产苯乙烯的主要原料,苯乙烯主要用来生产聚苯乙烯及其共聚物,如发泡聚苯乙烯(EPS),聚苯乙烯(PS),工程塑料(ABS),丁苯橡胶(SBR),不饱和树脂(UPR)。 本课题对苯与溴乙烷合成乙苯进行研究,主要探讨了含ZnO催化剂在溴乙烷与苯催化烷基化合成乙苯反应中的催化作用以及反应机理的初步讨论。 本课题研究的重点是含ZnO催化剂在溴乙烷与苯催化烷基化合成乙苯反应中的催化作用以及反应机理的初步讨论。 论文首先考察了载体为SiO2时ZnO负载量、反应温度、苯与溴乙烷的摩尔进料比、溴乙烷的质量空速、催化剂的焙烧温度等反应条件对溴乙烷转化率及产物分布的影响,确定450℃下焙烧的ZnO负载量为12%时制备的催化剂较好。在反应温度为240℃,苯与溴乙烷的摩尔进料配比为4：1,溴乙烷的质量空速为0.48h-1的条件下,得到最高的溴乙烷转化率和乙苯选择性。 论文中研究了SiO2和HZSM-5(Si:Al=140:1)两种载体上负载不同ZnO后的催化剂催化苯烷基化的活性,研究了不同的ZnO负载量对溴乙烷与苯反应合成乙苯的影响。结果表明在两种不同载体的催化剂上,溴乙烷的转化率和乙苯的选择性都随着ZnO负载量的增加而增加,说明ZnO对于溴乙烷与苯的烷基化反应有很强的催化促进作用,我们认为在反应过程中ZnO与生成的溴化氢(溴乙烷与苯反应得到)反应生成ZnBr2。ZnBr2为一种Lewis酸,可能是溴乙烷活化为乙基碳正离子的活性中心。 由于催化剂12%ZnO-SiO2和24%ZnO/HZSM-5表现出较好的催化性能,它们被选为详细研究的对象。在两种催化剂上研究反应温度和催化剂的酸性对溴乙烷转化率及产物分布的影响,结果表明在多乙苯与苯的烷基转移反应中,可能B酸是反应的活性中心。在两种催化剂上,随着反应温度的升高溴乙烷的转化率都升高,但是乙苯的选择性变化趋势不同。在24%ZnO/HZSM-5上,乙苯的选择性随温度的升高而增加;而在催化剂12%ZnO-SiO2上,乙苯的选择性随温度的升高而减小。这可能是由于24%ZnO/HZSM-5的B酸要比12%ZnO-SiO2的强,其对二乙苯与苯的烷基转移反应催化活性高,所以在催化剂24%ZnO/HZSM-5上乙苯的选择性随温度的升高而增加。 最后,结合上面一系列的实验数据对溴乙烷与苯反应的机理进行了