Current status and prospects of research on 1,4-dioxane pollution and treatment technologies in the water environment

1,4-dioxane pollution is characterized by its early identification, widespread sources and extensive distribution. The pollutant is highly mobile and persistent in the water environment and is classified as a B2(probable) human carcinogen. After reviewing recent researches on the pollution status,transport and transformation characteristics of 1,4-dioxane in the water environment, as well as the environmental pollution remediation and treatment technologies, and the status of environmental regulation,this paper addresses that the distribution of 1,4-dioxane in water bodies is significantly correlated with chlorinated hydrocarbon pollutants such as 1,1,1-trichloroethane(1,1,1-TCA) and trichloroethylene(TCE).It is noteworthy that 1,4-dioxane often occurs in symbiosis with 1,1,1-TCA and has a similarity contamination plume distribution to 1,1,1-TCA. The natural attenuation of 1,4-dioxane in groundwater environment is weak, but there is a certain degree of biological oxidation attenuation. Current methods for treating 1,4-dioxane pollution mainly include extraction-treatment technology, advanced oxidation treatment technology, modified biological treatment technology and phytoremediation technology, all of which have their limitations in practical application. Currently, there is no environmental regulation available for the 1,4-dioxane pollution worldwide, and no enforceable standard established for defining the health trigger levels of 1,4-dioxane in drinking water. Research on this contaminant in China is generally limited to the site or laboratory scale, and there are no studies on the environmental risk and quality standards for 1,4-dioxane in the water environment.

RING-OPENING POLYMERIZATION OF l,4-DIOXAN-2-ONE INITIATED BY LANTHANUM TRIS(2,6-DI-TERT-BUTYL-4-METHYLPHENOLATE)

The ring-opening polymerization of 1,4-dioxan-2-one （PDO） was carried out by lanthanum tris（2,6-di-tert-butyl-4- methylphenolate） （La（OAr）3） as novel single component initiaLor. The influences of polymerization reaction temperature and the molar ratio of monomer to initiator on the monomer conversion and molecular weight of poly（1,4-dioxan-2-one） （PPDO） were explored. PPDO with high viscosity average molecular weight of 1.95×10^5 can be prepared at 40℃ when [PDO]/ [La（OAr）3] molar ratio was 800. Mechanism investigation shows that the polymerization proceeds through a ＂coordination- insertion＂ mechanism with selective rupture of acyl-oxygen be,nd of PDO.

SYNTHESIS AND POLYMERIZATION OF 2-OXO-3-METHYLENE-5, 6-DIPHENYL-1,4-DIOXAN

A new cyclic monomer, 2-oxo-3-methylene-5, 6-diphenyl-1, 4-dioxan, was synthesized. Thestructure of the intermediates and the monomer were determined by IR,~1H NMR,^(13)C NMR andelemental analysis. This new monomer is different from other cyclic monomers in this series,it isa solid (mp 108--109℃)and not very reactive, but still can undergo free radical ring-openingpolymerization. The free radical polymerization was carried out at 130℃. The structure of theresulting polymer was discussed and charaterized by IR, ~1H NMR, ^(13)C NMR and elementalanalysis. The molecular weight of the polymer was estimated by viscosity determination.

SINGLE LANTHANUM TRIS(N-PHENYLETHYL-3,5-DI-t-BUTYLSALICYLALDIMINATO)S INITIATOR FOR RING-OPENING POLYMERIZATION OF 1,4-DIOXAN-2-ONE IN BULK

A rare earth Schiff base complex:lanthanum tris(N-phenylethyl-3,5-di-t-butylsalicylaldiminato)s [La(OPEBS)_3] was successfully applied as single component initiator for the ring-opening polymerization of 1,4-dioxan-2-one (PDO) in bulk.The influence of reaction conditions,such as polymerization temperature,the molar ratio of the monomer to initiator (M/I) on the monomer conversion and molecular weight of the polymer has been investigated.Poly(1,4-dioxan-2-one) with a viscosity-average molecular weight (My) o...

膜萃取-气相色谱/微分离子迁移谱检测水中的1,4-二恶烷

利用膜萃取-气相色谱/微分离子迁移谱（ME-GC / DMS）对水中的1，4-二恶烷污染物进行了检测。考察了射频电压、采样流速、膜渗透时间、Trap 预富集时间等参数对检测二恶烷的影响规律。结果显示：在优化条件下，二恶烷的定量线性范围为2.0～20.0μg / L，检出限为0.67μg / L。实验证明，二恶烷与5种氯代烃的混合物在 ME-GC /DMS 的二维分离谱图中得到特异性响应，增加了识别的准确性。该研究为发展现场实时监测地下水中污染物的方法提供了重要参考。

SO_4^(2-)/M_xO_y固体超强酸催化二甘醇合成1,4-二氧六环的研究

以二甘醇为原料,SO42-/MxOy型固体超强酸催化剂催化,在常压、气相条件下,固定床合成了1,4-二氧六环.考察了反应温度、进料速度对产品收率的影响.结果表明:在反应温度260℃,进料流速0.4mL/min时,1,4-二氧六环的产率为76.14%,是工业生产1,4-二氧六环较理想方法,具有良好的工业生产前景.

顶空气相色谱-质谱法测定洗浴用品及原材料中1,4-二氧杂环己烷残留量

提出了顶空气相色谱-质谱联用法测定洗浴用品及原材料中1,4-二氧杂环己烷残留量的方法。采用选择离子监测模式,以质荷比m/z43,58,88的特征离子进行定性分析;以质荷比m/z88的特征离子进行定量检测。1,4-二氧杂环己烷的质量浓度在500 mg.L-1以内与其峰面积呈线性关系,检出限（3S/N）为0.5 mg·kg^-1。加标回收率为92.8%-105.5%,相对标准偏差（n=6）为2.50%-6.35%。

六甲基二硅胺烷催化芳香醛与2,2-二甲基-1,3-二噁烷-4,6-二酮的缩合反应

在六甲基二硅胺烷的催化作用下,以芳香醛与2,2-二甲基-1,3-二噁烷-4,6-二酮为原料,经缩合反应合成了10种芳基亚甲基麦氏酸化合物.考察了反应温度、反应时间、催化剂用量等因素对反应的影响.确定了最佳反应条件为：取0.1 mol 2,2-二甲基-1,3-二噁烷-4,6-二酮,n（2,2-二甲基-1,3-二噁烷-4,6-二酮）∶n（芳香醛）=1.0∶1.1,催化剂用量为0.1 mol,反应温度为室温,反应时间为1.0 h,在上述反应条件下,产品收率可达86.8%~92.1%.

对甲苯磺酸催化乙二醇合成1,4-二氧六环

以对甲苯磺酸作催化剂,对乙二醇脱水制备1,4-二氧六环的反应进行研究。考察了催化剂用量、反应时间和反应温度等因素对收率的影响,得出最佳反应条件:催化剂用量为乙二醇质量的4.3%,反应时间50 min,收率可达84.82%。

La(OTf)_3催化合成2,2-二甲基-1,3-二噁烷-4,6-二酮

研究了在三氟甲基磺酸镧(La(OTf)3)的催化条件下,以丙二酸和丙酮为原料,乙酸酐为缩合剂合成了2,2-二甲基-1,3-二噁烷-4,6-二酮。考察了酸酮摩尔比、反应温度、反应时间及催化剂用量等因素对反应的影响。确定了其最佳反应条件为:取0.1 mol丙二酸,n(丙二酸)∶n(丙酮)=1.0∶1.1(mol/mol),催化剂用量为0.2 g/0.1 mol丙二酸,反应温度30℃,反应时间为3.0 h,在上述反应条件下,产品收率可达77.1%。

水相体系中磷钨酸催化Prins缩合反应合成4-苯基-1,3-二氧六环

比较了浓硫酸、HZSM-5分子筛、磺酸型CT-252树脂、磷钨酸铵和磷钨酸催化剂对甲醛水溶液与苯乙烯的Prins缩合反应的催化效果。实验结果表明,磷钨酸的催化性能最佳。以磷钨酸为催化剂,优化了甲醛水溶液与苯乙烯通过Prins缩合反应合成4-苯基-1,3-二氧六环的实验条件。实验结果表明,适宜的反应条件为:磷钨酸用量(基于反应体系的质量)12.0%,苯乙烯20 mmol,n(甲醛)∶n(苯乙烯)=4.0∶1,90℃下反应3.0 h。在此条件下,苯乙烯转化率达到87.3%,4-苯基-1,3-二氧六环的选择性为98.9%。使用后的磷钨酸催化剂经萃取蒸馏处理后,可循环使用3次,催化活性基本不变。该反应具有效率高且成本低的特点。

4-异丙基-5,5-二甲基-间-二氧杂环己-2-酮的合成

改进了中间产物２，２，４－三甲基－１，３－戊二醇的合成技术，使其收率显著提高，并采用新方法合成了环状碳酸酯４－异丙基－５，５－二甲基－间－二氧杂环己－２－酮。

1,3-2,4-二(3,4-二甲基)亚苄叉山梨醇溶解度的测定

利用基团贡献法计算了聚丙烯成核剂DDMBS的溶解度参数(δ=26.54J1/2.cm-3/2),在此基础上计算了部分溶剂与DDMBS样品的相容性参数,其中P(DDMBS～C6H5CH2OH)=26.94,P(DMDBS～C6H5CH2CH2OH)=35.15,P(DDMBS～1,2-二氧六环)=113.83,即苯甲醇是DDMBS成核剂的最好溶剂,其次是苯乙醇,再次是1,4-二氧六环;利用溶解度参数理论,预测DDMBS的混合溶剂为苯甲醇～甲醇和苯乙醇～甲醇;用浊度滴定法测定了成核剂DDMBS的溶解度参数,测定值为δ实验=25.24(J/ml)1/2,与用基团贡献法计算值基本一致;测定了DDMBS试样在不同溶剂中的溶解度,并建立了该成核剂试样在不同溶剂中的溶解度与温度的关系方程;在相同温度下,DDMBS在苯甲醇中溶解度稍大于在苯乙醇中的溶解度,DDMBS在1,4-二氧六环中的溶解度小于在苯甲醇、苯乙醇中的溶解度。

无溶剂下磷钨酸镧催化合成5-亚烃基-2,2-亚丁基-1,3-二噁烷-4,6-二酮

在LaPW12O40催化下,芳香醛和2,2-亚丁基-1,3-二噁烷-4,6-二酮在无溶剂条件下合成了8种新型5-亚烃基-2,2-亚丁基-1,3-二噁烷-4,6-二酮.当催化剂的用量为5%（摩尔分数）时,室温反应20~40 min,收率为87.6%~94.3%.此外,还探讨了LaPW12O40的催化机理.该方法具有条件温和,反应时间短且收率高的优点.催化剂LaPW12O40对环境友好且可循环利用.

木素及β-O-4型邻醌木素模型物与过氧化氢反应的初步研究

对二氧六环木素及β-O-4型邻醌木素模型物与过氧化氢的反应进行了初步研究。结果表明,二氧六环木素与过氧化氢反应后的降解产物中羰基明显增多,而且生成了醌型物质。二聚体β-O-4型邻醌木素模型物与过氧化氢反应的降解产物要比二氧六环木素与过氧化氢反应的降解产物简单得多,是较为理想的研究高得率浆木素邻醌发色基团与过氧化氢反应机理的简单模型化合物。

Synthesis of Crystallized BaWO₄Nanorods in a Microemulsion System

BaWO4 nanorods have been successfully synthesized in w/o microemulsion system containing barium ions via a simple reaction between Ba2+ and . The BaWO4 Nanorods were characterized by XRD, TEM, and SEM, respectively. Results showed that the solvents composition—volume ratio of 4-dioxane and distilled water—played the key role in the formation of BaWO4 Nanorods. Furthermore, the strong vibration at 925 cm﹣1 on its Raman spectrum indicated that the BaWO4 nanorods is good at stimulating Raman scattering in transient and steady-state, making it as a promising candidate material for laser with self-raman conversion of radiation inside the active medium.

1,4-二氧六环―盐酸预处理对麦秆化学成分的影响

用1,4-二氧六环―盐酸溶液对麦秆原料进行预处理,考察了预处理时间和盐酸浓度对原料化学成分含量的影响。研究结果表明,1,4-二氧六环―盐酸预处理可有效脱除麦秆中的木质素而保留绝大部分葡聚糖。预处理后浆料中木质素的脱除率随着预处理时间的延长和盐酸用量的增加而提高,高聚糖的降解率也有所增加,其中半纤维素的降解较为严重,而纤维素的降解率小于2%。

2，2－亚戊基－1，3－二氧六环－4，6－二酮与原甲酸三乙酯和脲素衍生物的反应

２，２－亚基－１，３－二氧六环－４，６－二酮与原甲酸三乙酯和脲素衍生物反应，合成了六个新化合物（４ａ－ｆ）．在它们的ＩＲ谱图中，没有羟基的特征吸收峰，表明４ａ－ｆ以分子内氢键形式存在．该类反应具有试剂安全、得率好、条件温和、操作简便等特点．

5-乙基-2-(4-氰基苯基)-1,3-二噁烷的合成

以溴乙烷和丙二酸二乙酯为原料合成2-乙基丙二酸二乙酯,收率为90.4%.2-乙基丙二酸二乙酯经还原和环合两步反应合成了目标产品5-乙基-2-(4-氰基苯基)-1,3-二噁烷,两步反应总收率为71.9%.产品经DSC确证了相变温度,并用IR和1H-NMR对其结构进行了表征.

用国产GDX-103色谱柱测定脂肪醇聚氧乙烯醚类产品中的1,4-二噁烷

用顶空气相色谱法,选择了色谱固定相和实验条件,用国产高分子多孔小球GDX-103色谱柱测定脂肪醇聚氧乙烯醚(AEO)及其硫酸盐(AES)和含有AES的餐具洗涤剂中的1,4-二噁烷。结果表明:所测7个AEO样品中1,4-二噁烷的质量浓度小于2μg.mL-1;所测9个AES样品中1,4-二噁烷质量浓度为6.0μg.mL-1-928.3μg.mL-1;所测8个餐具洗涤剂样品中1,4-二噁烷质量浓度为2.9μg.mL-1-59.7μg.mL-1。该方法测定1,4-二噁烷的标准曲线的相关系数为0.999 9,检出限为0.3μg.mL-1。