2，4-二硝基甲苯羰基化反应溶液的高效液相色谱测定

2,4-甲苯二氨基甲酸二乙酯(TDC)是一种重要的化工原料,也是合成2,4-甲苯二异氰酸酯(TDI)的中间体。TDC和TDI在世界各国都采用光气法生产,此法有严重的缺点即毒性太大;近年出现了羰基化法代替光气法的研究。我们也进行了这方     

气相色谱-质谱法测定复合食品包装材料中的2,4-二氨基甲苯

正在食品包装领域中,复合食品包装材料是应用最广的包装材料[1]。但在加工合成时,常常会使用含甲苯二异氰酸酯(TDI)的黏合剂,TDI极易水解产生致癌性的芳香胺,其主要成分为2,4-二氨基甲苯。2,4-二氨基甲苯又称甲苯二胺或间甲苯二胺,是一种常用的有机合成原料,呈无色针状或菱形结晶,其工业品多为褐色或灰绿色结晶。复合食品包装材料在使用过程中,TDI常常会水解,致使产生的2,4-二氨基甲苯迁移到食品中。2,4-二氨基甲苯     

甲苯二氨基甲酸甲酯分解合成甲苯二异氰酸酯反应系统的高效液相色谱分析

选用乙醇作为衍生剂,将甲苯二氨基甲酸甲酯分解制备甲苯二异氰酸酯(TDI)过程的中间产物甲苯单异氰酸酯(TMI)及最终产物TDI中的活泼基团-NCO进行封端保护,生成乙醇的衍生物,通过高效液相色谱对乙醇衍生物进行分析,实现了对TMI及TDI的定性及定量分析。高效液相色谱分析条件为:流动相甲醇-水(体积比6∶4),流速0.5mL/min,紫外光检测波长254nm。在一定的质量浓度范围内,TDI及TMI乙醇衍生物的线性相关系数均大于0.999,相对标准偏差均小于1.0%。本方法准确、简便、快速,能很好地满足甲苯二氨基甲酸甲酯分解合成甲苯二异氰酸酯反应系统中的反应物、中间产物以及目的产物的定量分析,也可用于工业TDI生产过程中甲苯单异氰酸酯及甲苯二异氰酸酯的定量分析。     

大分子量二苯甲酮光引发剂的合成及动力学研究

以4-羟基二苯甲酮(HBP)、甲苯-2,4-二异氰酸酯(TDI)、4,4′-二羟基二苯甲酮(DHBP)为原料,通过两步反应,合成了一种大分子量二苯甲酮光引发剂:HBP-TDI-DHBP-TDI-HBP(HTDTH).通过实时红外研究了HTDTH的光聚合动力学.结果表明,HTDTH是一种有效的光引发剂.采用HTDTH/胺光引发体系引发二缩三丙二醇二丙烯酸酯(TPGDA)聚合时,随着胺和引发剂浓度的增大,反应速率(R_p)和单体最终转化率(P)同时增大.     

新型二胺扩链剂对合成聚脲机械性能的影响

以咔唑为原料合成了新型扩链剂N-乙基-3,6-二氨基咔唑;将其与端氨基聚醚和甲苯-2,4-二异氰酸酯(TDI)经溶液聚合合成了新型聚脲;采用红外光谱表征了新型扩链剂和聚脲的结构.结果表明,以N-乙基-3,6-二氨基咔唑作为扩链剂合成聚脲时,随异氰酸酯质量分数的增加,凝胶时间逐渐变短;所制备的聚脲的拉伸强度达25MPa,断裂伸长率降低为105%.     

纳米氧化鏑/壳聚糖杂化材料的制备和抑菌性研究

用甲苯-2,4-二异氰酸酯(TDI)为功能化试剂,经过一定的物理﹑化学方法处理,使纳米氧化鏑和壳聚糖(CS)以TDI作为桥梁合成新材料DTC(Dy2O3-TDI-CS).重点研究了该材料对金黄色葡萄球菌和大肠杆菌的抑菌性能以及最低抑菌浓度(MIC),并且与壳聚糖的抑菌性进行了对比.实验表明该材料比壳聚糖有更好的抑菌性,...     

光(热)致变色剂:单和双吲哚啉螺苯并吡喃

用乙醇作溶剂,在哌啶存在下,通过2,3,3-三甲基-N-(β-羟乙基)吲哚啉碘化物(1)与3-或5-硝基水杨醛反应,分别制得螺环异构体(2a)与(2b)。它们再进一步与异氰酸苯酯进行加成反应,合成一对单螺环异构体(3a)与(3b),将2a 与2b 分别和2,4-二异氰酸甲苯酯(TDI)反应,合成一对双螺环异构体(4a)与(4b)。2a,3a,4a,4b 是光致变色化合物;2b 与3b 是热致变色化合物。     

基于α-羟烷基苯酮(HAPK)可聚合大分子光引发剂的合成及其引发三丙二醇双丙烯酸酯(TPGDA)光聚合动力学的研究

以α-羟烷基苯酮(HAPK)、甲苯-2,4-二异氰酸酯(TDI)、聚乙二醇600(PEG600)和丙烯酸-β-羟乙酯(HEA)为原料,通过3步反应,合成了一种可聚合大分子光引发剂:HAPK-TDI-PEG600-TDI-HEA(HTPTH).用IR对反应过程进行了监测.通过Photo-DSC研究了HTPTH引发三丙二醇双丙烯酸酯(TPG-DA)光聚合动力学,考察了光强、引发剂浓度对TPGDA光聚合动力学的影响.结果表明,随着引发剂浓度和光强的增大,最大反应速率对应的转化率、单体最终转化率、最大反应速率都增大,达到最大反应速率所需的时间减小.     

SiO2交联剂交联MMA聚合制备PMMA/SiO2纳米复合材料

用SiO2交联剂(SiO2HPA)交联甲基丙烯酸甲酯(MMA)自由基聚合制备PMMA SiO2纳米复合材料。采用两步法将可聚合乙烯基单体以化学键的形式键接到SiO2表面合成SiO2交联剂,首先利用过量的甲苯2,4二异氰酸酯(TDI)对SiO2纳米粒子表面进行化学修饰合成出表面带有高反应活性NCO基团的功能化SiO2粒子(SiO2TDI),SiO2TDI与丙烯酸羟丙酯(HPA)反应合成SiO2交联剂。系统研究了MMA单体与SiO2交联剂投料比及聚合时间对聚合反应的影响。此外,利用红外光谱(FT IR)、DSC、TGA、可见光光谱仪等实验手段对纳米复合材料进行了表征分析。结果表明,纳米SiO2粒子在复合材料中起着物理交联点和化学交联点作用,复合材料玻璃化转变温度(Tg)明显地高于其纯PMMA的玻璃化转变温度,随着纳米SiO2粒子含量的增加,复合材料玻璃化温度升高,而透明度明显降低。     

基于香豆素的比率型荧光探针对溶液及气相中三氟化硼的检测

合成了一种以香豆素为主体的具有高选择性及灵敏性的比率型荧光探针3-对甲基苯基-7-二乙氨基香豆素(TDC), 并将其用于溶液及气相中三氟化硼(BF₃)的即时可视化检测, 检出限为5.5×10^-7 mol/L. 通过荧光光谱、 紫外-可见吸收光谱和核磁共振波谱(¹⁹F NMR)等方法证实, 该探针与BF₃之间发生的路易斯酸碱反应会对TDC分子内电荷转移(ICT)过程产生影响, 从而引起光谱和溶液颜色的明显变化. 基于TDC分子制成的试纸能够实现裸眼检测溶液和气相中的BF₃.     

Toluene abatement on Ag-CeO2/SBA-15 catalysts: synergistic effect of silver and ceria

As a typical volatile organic compound, toluene is a hazardous material for human health and the environment, and currently, the development of catalysts for its oxidation into CO₂ and water is crucial. The series of Ag-CeO₂/SBA-15 catalysts is synthesized by wetness impregnation techniques and characterized by a number of physical-chemical methods (nitrogen [N₂] physisorption, small angle X-ray scattering [SAXS], transmission electron microscopy [TEM], and temperature-programmed reduction [TPR]). The toluene sorption and catalytic properties in toluene oxidation are studied. Small silver [Ag] and cerium oxide [ceria, CeO_2] particles with sizes below 3 nm are predominantly formed in the ordered structure of Santa Barbara Amorphous-15 [SBA-15]. The interactions between the Ag and CeO₂ nanoparticles are established. Temperature-programmed desorption of toluene [TPD-C₇H₈] analysis shows that physical adsorption of toluene occurs on pristine SBA-15 material, while the introduction of either silver or ceria to SBA-15 leads to the appearance of additional strongly bound chemisorbed toluene on such sites. When both Ag and CeO₂ are introduced, only chemisorbed toluene is formed over the Ag-CeO₂/SBA-15 catalyst, and the highest catalytic activity in toluene oxidation is observed over this catalyst (T_98% = 233 °C, 0.2% C₆H₅CH₃) that is attributed to the synergistic effect of ceria [CeO_2] and silver [Ag].     

Microwave-assisted acid hydrolysis of toluene diamine conjugates in urine samples for biomarkers in toluene diisocyanate analysis

Toluene diamines (TDAs) in urine have been used widely to determine the amount of toluene diisocyanate (TDI) absorbed by humans. Conventional hydrolysis to prepare a sample of urine takes approximately 16 h. An attempt is made to apply microwave-assisted heating (MAH) to reduce the duration of analysis. Urine collected from rats exposed to a mixture of 2,4- and 2,6-TDI was diluted with non-exposed human urine 1/1250-, 1/500- and 1/250-fold. The urine samples were hydrolyzed by both conventional heating and MAH. The hydrolysis efficiency obtained using MAH significantly exceeded that obtained using conventional heating. Hydrolysis by MAH required only 20 min, 48 times faster than with conventional heating. The use of the MAH method in hydrolysis was demonstrated to be reproducible, timesaving and efficient technique in measuring the concentration of urinary TDAs.     

Toluene methylation on AlPO4-Al2O3 catalysts (5–15 wt.% Al2O3)

The alkylation of toluene with methanol over AlPO₄-Al₂O₃ (5–15 wt.% Al₂O₃) catalysts produces a mixture of xylenes (XYL) although trimethylbenzenes (TMB) were also found. The TMB selectivity increased with temperature at the expense of XYL selectivity. Isomer distribution was approximately 48, 24 and 27 mol% foro-, m- andp-XYL, and 74, 26 and 0 mol% for 1,2,3-, 1,2,4- and 1,3,5-TMB, both quite different from the equilibrium isomer composition. The catalytic activity increased with alumina content, however, it decreased on increasing the calcination temperature in the 923–1273 K range. Good correlations between catalytic activity and the increase in acidic properties with Al₂O₃ loading (as determined by base chemisorption, in the gas phase,versus pyridine and 2,6-dimethylpyridine) have been obtained.     

A LC Separation and Quantification of o‐Toluene Sulphonamide and its Related Positional Isomers Using a Cellulose tris(3,5‐dimethyl phenylcarbamate)

A simple, rapid, selective and sensitive high performance liquid chromatographic method was developed for the separation and quantification of o‐Toluene Sulphonamide and its positional isomers which is an intermediate of Zafirlukast drug substance using a chiral column. Elution time was below 10 min in normal phase mode and ultra violet detection was carried out at 220 nm. Efficient separation was achieved on a Chiralcel OD‐H column using of n‐Hexane and 2‐Propanol mixture (50:50 v/v) as isocratic at 1.0 mL min⁻¹ flow rate. Resolutions between m‐Toluene Sulphonamide and p‐Toluene Sulphonamide isomers of o‐Toluene Sulphonamide were found to be >; 2.5. The calibration graphs for m‐Toluene Sulphonamide and p‐Toluene Sulphonamide isomers of o‐Toluene Sulphonamide were linear (R² > 0.999) when ranging from the limit of quantitation to 0.5%. The method is found to be selective, precise, linear, accurate and also robust. It was used for not only Quality assurance but also monitoring the synthetic reactions involved in the process development of Zafirlukast. The liquid chromatographic method is found to be specific and reliable for the determination of unreacted levels of positional isomers in reaction mass. This method was successfully validated according to the International Conference Harmonization (ICH) guidelines (Validation of Analytical Procedures: Test and Methodology Q2).     

顶空单液滴微萃取-气相色谱法测定水中苯系物

采用顶空单液滴微萃取样品处理方法分离富集水中苯系物,用气相色谱法进行测定.考察了不同萃取剂、萃取条件对检测结果的影响.苯、甲苯、对二甲苯的检出限分别为0.05,0.05,0.03 μg·L-1,三种苯同系物的相关系数分别为0.999 2,0.998 5和0.997 2,回收率分别为98.3%,101.9%和97.3%.     

Pt/TiO_2光催化降解甲苯

选择甲苯作为研究对象 ,探讨了在不同光源照射、不同光催化剂的作用下 ,气相甲苯的降解情况 .结果表明甲苯在紫外杀菌灯照射下有明显的光化学反应发生 .在光催化剂作用、黑光灯照射时 ,甲苯发生光催化氧化反应 ;并对催化剂在降解甲苯反应中的失活原因做了初步探讨     

甲苯二异氰酸酯的气相色谱-质谱分析

采用气相色谱－质谱分析甲苯二异氰酸酯（TDI）,以TDI80为例,对测试过程中样品的存放、溶剂及色谱条件的选择、组分定量作了探讨,获得满意的结果。该法无需标样,具有定性定量准确、简便的特点。     

Phase equilibrium measurements of (methane + benzene) and (methane + methylbenzene) at temperatures from (188 to 348) K and pressures to 13 MPa

New isothermal pTxy data are reported for (methane + benzene) and (methane + methylbenzene (toluene)) at pressures up to 13 MPa over the temperature range (188 to 313) K using a custom-built (vapor + liquid) equilibrium (VLE) apparatus. The aim of this work was to investigate literature data inconsistencies and to extend the measurements to lower temperatures. For (methane (1) + benzene (2)), measurements were made along six isotherms from (233 to 348) K at pressures to 9.6 MPa. At temperatures below 279 K there was evidence of a solid phase, and thus only vapor phase samples were analyzed at these temperatures. For the (methane (1) + methylbenzene (3)) system, measurements were made along seven isotherms from T = (188 to 313) K at pressures up to 13 MPa. Along the 198 K isotherm, a significant change in the data’s p,x slope was observed indicating (liquid + liquid) equilibria at higher pressures. The data were compared with literature data and with calculations made using the Peng–Robinson (PR) equation of state (EOS). For both binary systems our data agree with much of the literature data that also deviate from the EOS in a similar manner. However, the data of Elbishlawi and Spencer (1951) for both binary systems, which appear to have received an equal weighting to other data in the EOS development, are inconsistent with the results of our measurements and data from other literature sources.     

PERVAPORATION SEPARATION FOR TOLUENE/n-HEPTANE MIXTURE BY POLYIMIDE MEMBRANES CONTAINING FLUORINE

Five kinds of polyimides were synthesized using five dianhydrides (including 2,2-bis[4-(3,4-dicarboxyphenoxy)- phenyl] propane dianhydride (BPADA),3,3',4,4'-diphenylsulfone-tetracarboxylic dianhydride (DSDA),4,4'- (hexafluoroisopropylidene)-diphthalic anhydride (6FDA),1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA), and 4,4'-oxydiphthlic dianhydride (ODPA)) and 2,2-bis[4-(4-aminophenoxy)phenyl] hexafluoropropane (BDAF) via the two- step method that included polyaddition to form the polyamic aci...     

Oxidative synthesis of benzamides from toluenes and DMF

An interesting oxidative procedure for the synthesis of benzamides has been developed through the cleavage of sp³ CH bond of methyl arenes with N-substituted formamides. Various benzamides were prepared in low to moderate yields. Even though the yields are moderate in general, this new synthetic procedure provides another option for benzamide synthesis.