紫外可见光谱归一校正法检测2,4-二硝基苯酚

采用紫外可见光谱作为检测2,4-二硝基苯酚的方法,pH6或pH3时,2,4-二硝基苯酚的特征吸收峰分别为370 nm及260 nm处;在pH 3~6之间,两特征峰共存。文章提出一种简单的归一拟合方法,首先推导出260 nm处的吸收值与浓度的线性关系,再将pH不同的2,4-二硝基苯酚在370 nm处的吸收值校正到260 nm处。开发了一种简单快捷无需调节pH测定2,4-二硝基苯酚浓度的方法。     

高效液相色谱法测定工业废水中的硝基苯酚

利用高效液相色谱法建立了对于工业废水中的2,6-二硝基苯酚、2,4-二硝基苯酚以及苦味酸同时测定的分析方法,实验证明该方法简单快速、准确实用.     

用二六油制取2,4-及2,6-硝基苯酚

(I) 引言α-二硝基苯酚学名2, 4-二硝基苯酚〔2,4-C_6H_3OH(NO_2)_2〕,是一种淡黄到黄色的粉状結晶,熔点112.9℃,通常用2,4-二硝基氯化苯經碱性水解而成,工业品主要用于制造硫化染料,4-硝基,2-氨基苯酚和盐酸2,4-二氨基苯酚等。β-二硝基苯酚学名2,6-二硝基苯酚〔2,6-C_6H_3OH(NO_2)_2〕,系黄色至亮黄色結晶,熔点63～64℃,在比色法测定中用为单色pH指示剂,其顔色变化由无色至黄色,     

羧化改性壳聚糖微球的制备及吸附硝基酚的性能

采用反相悬浮环氧氯丙烷交联、氯乙酸羧甲基化制备交联羧化壳聚糖微球,用红外光谱和扫描电镜对微球进行表征,并用于2,4-二硝基苯酚的吸附研究。考察了吸附时间、溶液pH值、酚的浓度和NaCl等因素对2,4-二硝基苯酚吸附的影响。结果表明,羧化改性交联壳聚糖微球具有较好的耐酸碱性能,对2,4-二硝基苯酚有良好的吸附性能,在pH值为3.6条件下,吸附在瞬间就能达到平衡,吸附量达230 mg.g-1,吸附符合Freundlich等温方程。     

环境中痕量2，4-二硝基苯酚的检测方法的评价

近年来针对痕量2,4-二硝基苯酚的检测,出现了很多新的方法,本文筛选其中比较实用并有独创性的方法.进行对比总结.     

PBIO关键中间体5-氨基-2,4-二硝基苯酚的合成

系统地研究了以4,6-二硝基间二氯苯(DCDNB)为原料经单水解后氨解两步反应制备聚对亚苯基苯并咪口恶二唑(PBIO)的关键中间体5-氨基-2,4-二硝基苯酚(ADNP)的合成新路线及其优化条件。结果表明:采用NaOH在水溶剂中100℃回流下进行两个氯基的选择单水解反应,制得纯度98%以上的高收率5-氯-2,4-二硝基苯酚(CDNP);以1,4-二氧六环为溶剂,在150℃下使用氨水压力氨解另一个氯基合成ADNP,经精制后获得纯度98.5%以上、总收率达73.6%(以DCDNB计)的产品。产品经IR、1HNMR、13CNMR及MS等定性确认,合成过程已呈现有机污染少、操作方便、产品质量优异、经济性良好及易于产业化等特色,为进一步研发合成新型高性能材料PBIO及其新单体提供技术基础及中间体来源。     

1,5-二氟-2,4-二硝基苯的合成研究

采用1,5 二氯 2,4 二硝基苯与无水氟化钾反应合成1,5 二氟 2,4 二硝基苯的方法,对其氟化条件进行了研究,其最佳工艺条件为:在DMF溶剂中,1,5 二氯 2,4 二硝基苯与无水氟化钾摩尔比为1∶3,于110～115℃搅拌反应4h,产品收率为85%(以1,5 二氯 2,4 二硝基苯计),纯度为90%。     

新生态MnO2的制备及其对2,4-二硝基苯酚吸附性能的影响

以KMnO₄和MnSO₄·H₂O为原料,在常温常压和水热条件下制备新生态MnO₂,借助XRD、TEM、低温N₂吸附-脱附等手段对材料进行表征,比较不同制备方法对产物结构和吸附性能的影响。结果表明,反应温度和压力对新生态MnO₂的形貌和吸附性能有较大影响,常温常压下合成产物均为短棒状,水热合成产物为介孔纤维,对2,4-二硝基苯酚的吸附效果优于常温常压合成产物。新生态MnO₂对2,4-二硝基苯酚的等温吸附和吸附动力学分别符合Langmuir等温式(R²>0.99)和准二级吸附动力学方程(R²>0.99),说明2,4-二硝基苯酚在新生态MnO₂上为单分子层吸附和化学吸附。溶液pH值能显著影响2,4-二硝基苯酚在新生态MnO₂上的吸附,在pH=7时最大吸附量为2.539 mg/g。     

减肥产品中非法添加2,4-二硝基苯酚的检测研究进展

2,4-二硝基苯酚(DNP)在工业上常作为生产农药和染料的化工材料。20世纪初有欧美国家的研究者发现DNP具有减肥功效，被用作减肥产品进行销售，但后期研究发现DNP具有严重的副作用而被禁用。由于DNP获得途径广泛，价格便宜，近年来有非法商贩将其非法添加进减肥产品中以获得暴利。本文综述了2,4-二硝基苯酚对人体的危害及其减肥机理，并对DNP检测的前处理和分析方法进行了归纳，旨在为DNP检测方法的研究提供参考。     

2,4-二硝基苯苄醚合成改进及表征

以2,4-二硝基酚、苄基氯等为原料,合成了2,4-二硝基苯苄醚。从反应机理角度并用正交实验研究了Williamson醚合成中反应溶剂、反应温度、反应时间等因素对产品收率的影响,最终优化了反应条件,反应收率由75％提高到91．2％。     

2,4-二氯苯甲酸的合成研究

提出了经氨氧化法制得 2 ,4 二氯苯腈 ,然后水解得到 2 ,4 二氯苯甲酸的合成路线。 2 ,4 二氯甲苯在合适的催化剂和反应条件下 ,2 ,4 二氯苯腈的产率为 89 5 % ,经简单水洗后 ,产品纯度为 98 9%。 2 ,4 二氯苯腈在硫酸中较温和条件水解得到 2 ,4 二氯苯甲酸 ,产率为 95 5 %。     

3-氨基-4-甲氧基乙酰苯胺合成新工艺

以 2 ,4-二硝基氯苯为原料 ,经甲醇醚化先制得 2 ,4-二硝基苯甲醚 ,再经 Raney镍催化氢化得 2 ,4-二氨基苯甲醚 ,不分离直接进行选择性酰化 ,合成出重要分散染料中间体 3-氨基 - 4-甲氧基乙酰苯胺 ,品质稳定 ,全程收率大于 80 %。     

反,反—2,4—二甲基—5—芳基—戊—2,4—二烯酸的合成

以取代苯甲醛为原料,采用醇醛缩合反应和珀金反应完成了反,反－２,４－二甲基－５（对硝基苯基）戊－２,４－二烯酸和反,反－２,４－二甲基－５－（间硝基苯基）戊－２,４－二烯酸的有效全合成,并确定了最佳反应条件,化合物３ｂ为尚未见文献报道的新化合物,其结构经红外光谱,核磁共振证实。     

Adsorption equilibrium characteristics of 2,4-Dichlorophenoxyacetic acid and 2,4-Dinitrophenol on granular activated carbons

Adsorption characteristics of 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2,4-Dinitrophenol (2,4-DNP) onto granular activated carbon (GAC) were studied to obtain basic information on their removal from aqueous solution. Single component adsorption equilibria of 2,4-D and 2,4-DNP dissolved in water have been measured for three kinds of GACs (F400, SLS103, and WWL). In case of 2,4-D, the magnitude of adsorption capacity was in the order of F400> SLS103>WWL, and that for 2,4-DNP was SLS103> F400> WWL. The influence of temperature and initial pH of aqueous solution on adsorption has been discussed in detail by using the Sips equation.     

3-氨基-4-甲氧基乙酰苯胺合成新工艺

以2,4-二硝基氯苯为原料,经甲醇醚化先制得2,4-二硝基苯甲醚,再经Raney镍催化氢化得2,4-二氨基苯甲醚,不分离直接进行选择性酰化,合成出重要分散染料中间体3-氨基-4-甲氧基乙酰苯胺,品质稳定,全程收率大于80％。     

膜生物反应器对水源水中微量二氯酚的去除

通过实验室小试，研究了一体式膜生物反应器（MBR）对微污染湖水中的微量2,4-二氯酚（2,4-DCP）的去除效果。64 d的连续试验证实，当进水2,4-DCP浓度在2～200 μg·L-1时，MBR对2,4-DCP的平均去除率达936%。出水2,4-DCP浓度平均为428 μg·L-1，满足《城市供水水质标准》的要求。同时采用间歇试验对MBR去除2,4-DCP的机理进行了研究，证实生物作用在2,4-DCP的去除中起主要作用，MBR对2,4-DCP的去除符合零级动力学过程，降解速率常数为106 μg·L-1·min-1。此外，试验证实MBR对DCP的去除是基于二级基质原理，而向反应器内投加葡萄糖并不能促进MBR对2,4-DCP的去除。     

Adsorption of 2,4-dichlorophenol from Aqueous Solution by a New Low-Cost Adsorbent – Activated Bamboo Charcoal

Adsorption experiments were conducted to study the removal of 2,4-dichlorophenol (2,4-DCP) from aqueous solution by a new low-cost adsorbent-activated bamboo charcoal. The results showed that acidic pH was favorable for the adsorption and removal of 2,4-DCP. Higher initial 2,4-DCP concentrations led to higher adsorption capacity. Most of the adsorption of 2,4-DCP occurred within the first 5 min, and about 90% of 2,4-DCP were removed from solution. After 5 min, the adsorption capacity increased slowly with contact time and the adsorption reached equilibrium in less than 100 min. As the adsorbent dose was increased, the removal of 2,4-DCP was increased, while the equilibrium time was slightly affected. Adsorption kinetics could be best described by the pseudo-second-order model, independent of adsorbent dosages. The adsorption behavior of 2,4-DCP onto bamboo charcoal fitted both Langmuir and Freundlich isotherms well, but followed Freundlich isotherm more precisely. This study demonstrated for the first time that activated bamboo charcoal could be used for the removal of 2,4-DCP in water treatment.     

电-生物体系的运行方式对二氯酚还原降解的影响

废水中较高浓度的2,4-二氯酚(2,4-DCP)以溶解态和胶体2种形态存在。研究了间歇式电辅助微生物体系(IEMS)和连续式电辅助微生物体系(CEMS)对较高浓度2,4-DCP的还原降解效果。结果表明CEMS对溶解性2,4-DCP的降解符合零级反应动力学特征,动力学常数为0.245 h-1,对2,4-DCP降解中间产物邻氯酚(2-CP)和对氯酚(4-CP)的降解也为零级反应,动力学常数分别为0.048、0.081 5 h-1。IEMS在停止电辅助期间对胶体态2,4-DCP的水解效率远高于CEMS,2个体系均为零级反应,动力学常数分别为0.083 4、0.027 1 h-1。较高浓度的2,4-DCP宜采用IEMS处理。     

Synthesis of bis(2,4-diphenylbutyl) phthalate and its application as a plasticizer for poly(vinyl chloride) from waste polystyrene

Bis(2,4-diphenylbutyl) phathalate, a plasticizer for poly(vinyl chloride) (PVC), was synthesized from 2,4-diphenyl-1-butene obtained by a thermal decomposition under reduced pressure of waster polystyrene. The heat stability of bis(2,4-diphenylbutyl) phthalate was determined by thermogravimetric analysis and compared with typical plasticizers. It was recognized that bis(2,4-diphenylbutyl) phthalate showed high heat resistant. A test sheet of plasticized PVC with bis(2,4-diphenylbutyl) phthalate and bis(2-ethylhexyl) phthalate was prepared. The test sheet was used for determination of the plasticizing performance of bis(2,4-diphenylbutyl) phthalate. Although the effect of bis(2,4-diphenylbutyl) phthalate imparting flexibility to PVC is poorer than that of bis(2-ethylehexyl) phthalate, the former phthalate is well compatible with PVC and exceedingly heat-resistant.     

Synthesis and Characterization of Molecularly Imprinted Polymer Membrane for the Removal of 2,4-Dinitrophenol

Molecularly imprinted polymers (MIPs) were prepared by bulk polymerization in acetonitrile using 2,4-dinitrophenol, acrylamide, ethylene glycol dimethacrylate, and benzoyl peroxide, as the template, functional monomer, cross-linker, and initiator, respectively. The MIP membrane was prepared by hybridization of MIP particles with cellulose acetate (CA) and polystyrene (PS) after being ground and sieved. The prepared MIP membrane was characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. The parameters studied for the removal of 2,4-dinitrophenol included the effect of pH, sorption kinetics, and the selectivity of the MIP membrane. Maximum sorption of 2,4-nitrophenol by the fabricated CA membrane with MIP (CA-MIP) and the PS membrane with MIP (PS-MIP) was observed at pH 7.0 and pH 5.0, respectively. The sorption of 2,4-dinitrophenol by CA-MIP and PS-MIP followed a pseudo–second-order kinetic model. For a selectivity study, 2,4-dichlorophenol, 3-chlorophenol, and phenol were selected as potential interferences. The sorption capability of CA-MIP and PS-MIP towards 2,4-dinitrophenol was observed to be higher than that of 2,4-dichlorophenol, 3-chlorophenol, or phenol.