| 题名 | 二苯甲酮类紫外防晒剂BP-4氯化消毒研究：机理，动力学及毒性评价 |
| 作者 | 肖铭 |
| 学位类别 | 博士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 杜宇国,魏东斌 |
| 关键词 | BP-4 reaction mechanism reaction kinetics influencing factors toxicity test 反应机理推导 反应动力学 影响因素 毒性测试 BP-4 |
| 其他题名 | Chlorination of UV-filter Benzophenone-4： Mechanisms， Kinetics and Toxicity Evaluation |
| 学位专业 | 环境科学 |
| 中文摘要 | 二苯甲酮作为杀虫剂，农药，医药和个人护理用品中的主要成分，在使用后，可经洗浴，游泳，土地淋洗等过程进入环境，并最终进入污水处理氯消毒环节。BP-4是使用量较大的一种二苯甲酮类紫外防晒剂。其水溶性好，化学性质相对稳定，在多个地区的环境水体中均有检出。本文以BP-4为主要研究对象，综合运用核磁、UPLC-MS及GC-MS等手段，并结合有机化学反应原理，模型计算，毒性测试等方法对BP-4在氯消毒过程中的转化机理，反应动力学，毒性，影响转化各因素等进行了深入细致的研究。并且在BP-4研究的基础上，拓展研究了环境中常见离子溴与碘共存条件下的氯消毒反应。对于揭示BP-4潜在环境风险有很大的意义。论文主要开展了以下几个方面的研究工作： 使用UPLC-MS、GC-MS对不同条件下（pH，NaClO剂量，反应时间）BP-4氯消毒反应的反应产物混合物进行了分离。在良好分离的基础上，对产物的一级质谱，二级质谱进行了分析，初步确定了BP-4氯消毒过程中生成的13种产物结构。对于其中的2个产物，通过控制反应条件分离得到其纯品，并进行了核磁分析。在产物结构鉴定的基础上，使用化学计算并结合有机化学反应原理，我们对各产物生成的路径进行了推导和阐述。总的来说，BP-4氯消毒反应机理包含五种反应类型：第一种是BP-4及其中间产物的氯代反应，反应生成一氯代，二氯代以及三氯代产物；第二种是Baeyer-Villiger氧化，将二苯甲酮结构转化为苯酯结构；第三种是酯水解反应，生成苯酚类或苯甲酸类产物。第四种是脱羧反应，将苯甲酸类型中间产物的羧基替换成氯；第五种是脱磺酸反应，经氯的取代将苯环上磺酸基脱去。 然后，我们对BP-4氯消毒反应各方面的特征进行了进一步的探索。动力学方面，我们发现在NaClO过量的情况下，BP-4氯消毒反应符合准一级动力学方程。不同条件下的反应半衰期在7.48 s 到126.03 s范围内。此外，反应体系的pH值对所发生的反应类型有很大的影响，其中酸性条件pH 4.6条件下的反应类型最为丰富，五种反应皆能发生。而pH 7.5条件和pH 11条件下磺酸基取代，脱羧以及羟基间位氯代反应等会受到一定程度的抑制。NaClO剂量的影响则表现在，NaClO的剂量越大，反应进行得越彻底。毒性方面，我们对BP-4在各条件下氯消毒反应生成的产物混合物的遗传毒性进行了测定，结果表明，在某些反应条件下生成的产物混合物，其遗传毒性有上升的现象。最后，在北京采集了两个室内游泳池水样以及两个室外游泳池水样，对其中的BP-4及其氯消毒产物进行了定性定量检测，水样中检出了BP-4及3-Cl-BP-4。所检出的BP-4的浓度分别为40.22 ng·L-1 and 54.57 ng·L-1。由于3-Cl-BP-4没有标准品，很难对其含量做精确的判断。鉴于其结构与BP-4类似，理论上离子化效率接近，因此用BP-4的标准曲线代替其标准曲线，计算出水样中3-Cl-BP-4的含量分别为121.56 ng·L-1 和49.44 ng·L-1 。 环境中Br-和I-离子是常见的自然存在的离子。为了进一步让研究贴近实际环境中BP-4氯消毒反应的情况，我们对Br-离子和I-离子共存条件下的BP-4氯消毒反应分别进行了研究。结果表明，在Br-离子共存时，除了此前检测到的BP-4氯代产物，还检测出了11种新的含溴产物。在产物结构鉴定的基础上，我们对产物生成的路径进行了研究，在此反应体系中，BP-4首先发生亲电反应生成一卤代或二卤代产物。这些产物可以被进一步氧化生成卤代酯产物。所生成的卤代酯产物又可以发生水解反应，生成呋喃类杂环结构的单环产物。反应的pH对这些产物的生成有比较大的影响，不同pH条件下，产物的种类不同。NaClO的剂量则与BP-4母体的消耗量有很大关系。在环境水样中添加BP-4与Br-，并对其氯消毒过程进行了模拟。主要含溴消毒产物皆有检出，消毒后样品急性毒性有显著升高。 在I-离子共存时，除了此前检测到的BP-4氯代产物，我们还检测到了三个含碘的产物。主要为一碘代BP-4及水解后的单苯环碘代产物。 |
| 英文摘要 | As main ingredients in pesticides, pharmaceuticals and some other personal care products, Benzophenone-type chemicals could be washed off skin and clothing and eventually enter wastewater treatment plants. BP-4(2-hydroxyl-4-methoxybenzophenone-5-sulfonic acid) is one of the most frequently used BP-type chemicals, and has been detected out in ambient waters in many regions around the world. This paper was a comprehensive study about the chlorination process of BP-4 involving transformation products identification, reaction mechanism deduction, toxicity changes measurements, reaction kinetics study and influent facts (pH, doses of NaClO, coexistence of Br- and I-) study. The results would provide valuable basis for the evolution of the potential environmental risks of BP-4. The specific introduction of these contents are as follows. First, we used UPLC-MS and GC-MS to separate transformation products generated in BP-4 chlorination system with different pH, doses of NaClO and reaction times. 13 transformation product’s mass spectra were analyzed and their structures were deduced. Via controlling experiments conditions, two products were separated as pure products adequate for NMR analysis to further verified proposed structures. On the basis of products identification, combined with principles of organic chemistry and model computation, the mechanism were proposed. Generally speaking, five types of reactions were involved. The first is chlorination which forms mono-, di- or tir-chlorinated products. The second is Baeyer-Villiger oxidation resulting the generation of ester products. The third is hydrolysis of the ester products. The fourth is decarboxylation of the benzoic-type hydrolysis products and the fifth is desulfonation which replaces sulfonic group on benzene ring with chlorine atom. Then, we further explored the reaction characteristics of the chlorination of BP-4. In reaction kinetics respect，we discovered that reaction of BP-4 with excessive NaClO followed a pseudo-first-order model. The half-lives (t1/2) for BP-4 chlorination under different reaction conditions ranged from 7.48 s to 126.03 s. In influencing factors respects, pH had a great impact on the reaction. Under pH 4.6, all five types of reaction mention could take place while desulfonation and dichlorination of BP-4 or its intermediates were hindered under pH 7.5 and pH 11. Higher doses of NaClO would promote the elimination of BP-4 and the formation of smaller molecule products. In toxicity test respect, we found that the genotoxic potentials of reaction solutions rose after the chlorination process. What’s more, four swimming pool samples in Beijing were collected and analyzed, BP-4 and 3-chloro-BP-4 were detected, indicating the occurrence of BP-4 chlorination in the environment. Br- and I- are both ions naturally exist in the ambient water. We studied the chlorination process of BP-4 in the presence of bromide and iodide ions respectively. When Br- existed in the reaction system, 11 new brominated products were formed besides chlorinated products mentioned above and their formation pathways were proposed. BP-4 would first undertake electrophilic substitution forming mono- or di-halogenated products, then be oxidized to esters. The ester products could further hydrolyze to phenol derivatives And the catechol intermediate could be transformed into furan-like heterocyclic products. pH had a great impact on the product species while NaClO doses influenced the elimination of BP-4. Ambient water were spiked with bromide ions and BP-4, most of brominated by-products were detected and the acute toxicity significantly rose after the chlorination process. When I- existed in the reaction system, 3 new iodinated products were detected and identified. |
| 公开日期 | 2015-07-08 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/15624]  |
| 专题 | 生态环境研究中心_中国科学院环境生物技术重点实验室 |
| 推荐引用方式 GB/T 7714 | 肖铭. 二苯甲酮类紫外防晒剂BP-4氯化消毒研究：机理，动力学及毒性评价[D]. 北京. 中国科学院研究生院. 2014. |
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