A straightforward synthesis in aqueous medium of enantiomerically enriched S(-)2,2′-dihydroxy-1,1′-binaphthyl

Chiral, atropisomeric 2,2'-dihydroxy-1,1'-binaphthyl has been extensively used to direct asymmetric processes. Its key role in asymmetric catalysis has spurred efforts to synthesize it in the optically pure form, but the reported synthetic routes have a significant environmental impact. In an aqueous peroxydase-cyclodextrin system the oxidative coupling of 2-naphthol took place very rapidly in almost quantitative yield and resulted in an enantiomeric excess. This one-pot synthesis do not require any organic solvents and oxidising metal cations.     

酸雨对污染环境中重金属化学行为的影响

综述了酸雨对污染环境中重金属化学行为的影响。在酸雨作用下 ,不同环境介质中重金属活性明显增强 ,化学形态转化明显 ,迁移能力和生态危害能力亦明显加强。探讨了控制酸雨发生、重金属污染环境修复技术以及开展复合污染环境化学风险评价的必要性     

有机物的结构──活性定量关系及其在环境化学和环境毒理学中的应用

有机物的结构──活性定量关系及其在环境化学和环境毒理学中的应用王飞越（北京大学城市与环境学系，北京１００８７１）陈雁飞（武汉大学环境科学系）最近几十年来，有机物结构──活性定量关系研究（ＱＳＡＲ，ＱｕａｎｔｉｔａｔｉｖｅＳｔｒｕｃｔｕｒｅ－Ａｃｔｉｖ...     

Principles and perspectives

BACKGROUND, AIM AND SCOPE: With respect to the enormous increase of chemical production in the last decades and the tens of thousands of individual chemicals on the market, the permanent improvement of chemical management is a permanent target to achieve the goals of sustainable consumption and production set by the WSSD in Johannesburg 2002. MAIN FEATURES: Several approaches exist to describe sustainability of chemistry. However, commonly agreed criteria are still missing. There is no doubt that products of modern chemistry help to achieve important goals of sustainability and that significant improvements have occurred regarding direct releases from production sites, but several facts demonstrate that chemistry is far from being sustainable. Still too many chemicals exhibit hazardous characteristics and pose a risk to health and environment. Too many resources are needed to produce chemicals and finished products. RESULTS AND CONCLUSION: Therefore, a strategy for sustainability of chemistry should be developed which comprises the following main elements: 1. Sustainable chemicals: sustainable chemical management includes a regulatory framework which makes no difference between new and existing chemicals, contains efficient information flow through the supply chain which allows users to handle chemicals safely and offers an authorisation procedure and/or an efficient restriction procedure for substances of high concern. This regulatory scheme should promote the development of inherently safe chemicals. 2. Sustainable chemical production: Sustainable chemical production needs the development and implementation of emerging alternative techniques like selective catalysis, biotechnology in order to release less CO2 and less toxic by-products, to save energy and to achieve higher yields. Information exchange on best available techniques (BAT) and best environmental practices (BEP) may help to promote changes towards more sustainability. 3. Sustainable products: An integrated product policy which provides a framework for sustainable products promotes the development of products with a long-term use phase, low resource demand in production and use, low emission of hazardous substances and properties suitable for reuse and recycling. This may be promoted by eco-labelling, chemical leasing concepts and extended information measures to enhance the demand of consumers and various actors in the supply chain for sustainable products. RECOMMENDATION AND PERSPECTIVE: Important tools for the promotion of sustainable chemistry are the abolition of barriers for innovation in legislation and within the chemical industry, more transparency for all users of chemical products, a new focus on sustainability in education and research, and a new way of thinking in terms of sustainability.     

桐油水解制备咪唑啉缓蚀剂及其量子化学研究

目的 开发原料价廉易得、能实际应用的缓蚀剂。方法 以桐油为原料,水解后得到桐油酸,然后与二乙烯三胺经过酰胺化和环化反应,生成桐油咪唑啉缓蚀剂。在模拟现场环境的条件下对所合成的桐油咪唑啉缓蚀剂进行电化学测试和高温高压性能评价。利用量子化学计算对桐油咪唑啉缓蚀剂的分子动力学进行模拟,探讨其在Fe表面的吸附作用。结果 红外光谱显示,桐油水解后可生成桐油酸,最终合成物为桐油咪唑啉。电化学测试表明,随着桐油咪唑啉缓蚀剂添加量的增大,20#测试钢片的自腐蚀电位逐渐提高,腐蚀电流降低。高温高压模拟实验显示,加入油酸咪唑啉后,腐蚀速率明显降低,由0.3181 mm/a降到了0.0392 mm/a。量子化学计算表明,桐油咪唑啉分子中的咪唑啉环会平行吸附于铁表面,形成一层缓蚀剂膜。结论 价廉易得的桐油经水解后可得桐油酸,再与二乙烯三胺经过酰胺化和环化反应最终合成了桐油咪唑啉缓蚀剂。该缓蚀剂添加量越大,对20#钢片的缓蚀效果越好,呈现出了较好的缓蚀效果,其分子结构中的咪唑环能平行吸附于铁表面,属于抑制阳极型缓蚀剂。     

Observation and analysis of atmospheric volatile organic compounds in a typical petrochemical area in Yangtze River Delta, China

Volatile organic compounds (VOCs) are a kind of important precursors for ozone photochemical formation. In this study, VOCs were measured from November 5th, 2013 to January 6th, 2014 at the Second Jinshan Industrial Area, Shanghai, China. The results showed that the measured VOCs were dominated by alkanes (41.8%), followed by aromatics (20.1%), alkenes (17.9%), and halo-hydrocarbons (12.5%). The daily trend of the VOC concentration showed a bimodal feature due to the rush-hour traffic in the morning and at nightfall. Based on the VOC concentration, a receptor model of Positive Matrix Factorization (PMF) coupled with the information related to VOC sources was applied to identify the major VOC emissions. The result showed five major VOC sources: solvent use and industrial processes were responsible for about 30% of the ambient VOCs, followed by rubber chemical industrial emissions (23%), refinery and petrochemical industrial emissions (21%), fuel evaporations (13%) and vehicular emissions (13%). The contribution of generalized industrial emissions was about 74% and significantly higher than that made by vehicle exhaust. Using a propylene-equivalent method, alkenes displayed the highest concentration, followed by aromatics and alkanes. Based on a maximum incremental reactivity (MIR) method, the average hourly ozone formation potential (OFP) of VOCs is 220.49?ppbv. The most significant source for ozone chemical formation was identified to be rubber chemical industrial emissions, following one by vehicular emission. The data shown herein may provide useful information to develop effective VOC pollution control strategies in industrialized area.     

成都双流夏秋季环境空气中VOCs污染特征

为了解成都市大气污染重点防治区域——双流地区的环境大气中挥发性有机物(VOCs)的污染特征和来源,2016年8月30日~2016年10月7日,VOCs外场观测在成都市双流区展开.结果表明,在线观测期间,采样站点总的大气挥发性有机物(TVOCs)的平均体积分数为(45. 15±43. 74)×10-9,其中烷烃的贡献最大(29%),其次是芳香烃(22%)、卤代烃(17%)、含氧挥发性有机物(OVOCs,15%)、烯烃(9%)、乙炔(7%)、乙腈(1%);优势物种为丙酮、二氯甲烷、乙炔、乙烯、苯、甲苯、间/对-二甲苯、丙烷、1,2-二氯乙烷以及丁酮.通过比较VOCs的化学反应消耗速率发现,反应活性最大的为芳香烃,其次是烯烃;反应活性最强的物种为苯乙烯、间/对-二甲苯、异戊二烯、乙烯等.整个观测期间,有两次明显的生物质燃烧活动.国庆假日期间,TVOCs浓度相比之前明显上升,平均体积分数达57. 65×10-9,其中,短链烯烃、卤代烃以及OVOCs浓度上升最为显著.分析某些关键的非甲烷总烃(NMHCs)和OVOCs的日变化特征发现,其变化规律反映了双流地区不同源排放特点.双流区环境空气中VOCs受本地工业源排放影响较大.     

影响大气汞化学过程的敏感因子分析

为了分析汞在大气中的化学行为,在一个化学模式中加入汞的气相、气液平衡和液相反应,模拟大气汞及其化合物的演变规律,并分析了气象因子(云、光解率、温度)和化学因子(气态O3、H2O2、HO2、OH和气态零价汞Hg0(g))的初始体积分数对各形态汞及其化合物浓度和Hg0(g)转化率的影响.模拟结果表明,在中等大气污染条件下,Hg0(g)的每小时平均转化率为2.91%.敏感性试验结果表明,云量、光解率、温度、O3和Hg0(g)的初始体积分数对不同形态汞的影响较为显著.云量的增加、光解率的增加、臭氧初始体积分数的升高,各形态汞的平衡时间缩短,除气态氧化汞和一价汞离子外,其他形态汞的平衡浓度均会降低,Hg0(g)的转化率增加.温度增加将抑制Hg0(g)的转化.Hg0(g)的初始体积分数增加,各形态汞的浓度升高,但其平均转化率没有显著变化.不同因子对汞化学过程的相对作用对区域或全球大气汞的环境模拟具有指导意义.     

中国中东部地区地表水环境锶元素地球化学特征研究

水环境中锶的含量及其变化、地理分布及其控制因素等特征的研究有助于认识区域水文地球化学特征及流域盆地岩石风化速率等地球化学行为,因此河流环境中锶的地球化学行为是地球化学研究的重要课题之一。对我国中东部地区部分河流水体中溶解态锶含量进行了分析研究发现,与世界上主要河流溶解态锶含量平均值0.078 mg/L相比,中国中东部地区河水中的锶含量(0.139 mg/L)明显偏高。分析研究表明,中国中东部地区河水中的锶主要源于蒸发盐岩和碳酸盐岩的风化作用,流域锶含量从南向北逐渐增加的现象主要受流域岩石或沉积物类型的控制,化学风化作用越强烈,河流锶含量越高。除了受区域岩性的影响外,气候条件对流域河水中的锶含量水平及地理分布起到一定的控制作用。     

湖北丹江口水库主要离子化学季节变化及离子来源分析

2004～2006年对丹江口水库中的5个点位水质的 t 、pH、EC、TDS、ORP、SO^2-₄、Cl^-、NO^-₃、HCO^-₃、Ca²⁺、Mg²⁺、Na⁺、K⁺和Si进行了测定.综合运用方差分析及主成分分析对它们的季节变化及其来源进行了研究.结果表明,丹江口库区水体呈弱碱性,属于弱矿化度水,水质类型为HCO^-₃-Ca型水.主要阴、阳离子浓度范围为：Cl^-,（4.0±0.5～6.9±1.8）mg·L^-1;NO^-₃,（4.6±0.9～6.8±1.7）mg·L^-1;SO^2-₄,（24.3±2.7～35.4±6.9） mg·L^-1;HCO^-₃,（133.0±11.7～153.5±29.6）mg·L^-1;Na⁺,（2.0±0.3～5.3±1.0）mg·L^-1;K⁺,（0.7±0.09～1.6±0.7） mg·L^-1;Ca²⁺,（33.0±2.1～46.6±0.8）mg·L^-1;Mg²⁺,（8.0±2.5～10.5±3.2）mg·L^-1.方差分析显示除HCO^-₃和Si外,t、pH、EC、TDS、ORP、SO^2-₄、Cl^-、NO^-₃、Na⁺、K⁺、Ca²⁺、Mg²⁺都表现出了显著的季节性差异,主要离子化学汛期浓度均小于对应的非汛期浓度.Na⁺和Mg²⁺的浓度只表现出秋汛<秋季,NO^-₃和SO^2-₄浓度却呈现出秋汛>秋季,这主要归因于降雨的大气沉降对水化学的贡献不同.HCO^-₃占主要阴离子的75%～88%,Ca²⁺和碱土金属分别占主要阳离子的60%～80%和87%～96%,表明碳酸盐岩风化是水体质子的主要来源及主要化学风化类型.参照我国及世界卫生组织饮用水标准,主要离子的浓度并未对人体产生危害.