2, 4-己二炔-1, 6-二乙基脲的显色动力学

目的对2,4-己二炔-1,6-二乙基脲(KE)发生固相聚合反应时的显色动力学规律进行研究,为其作为商业化时间温度指示剂的应用提供指导。方法通过单因素法,分别从浓度、时间、温度3个方面对2,4-己二炔-1,6-二乙基脲在聚合反应过程中的显色动力学规律进行研究,利用分光密度仪对光密度值进行测定,并通过计算求得聚合反应的反应级数及反应活化能。结果随着浓度增大或温度升高,KE聚合反应速率逐渐增大,随加热时间的增长,反应速率先增加后减小,在上述条件下,时间温度指示剂的颜色均不断变深;通过计算得到该聚合反应的反应级数为0.31,活化能为37.09 k J/mol。结论 KE作为一种新型的时间温度指示剂,其视觉响应信号易于识别;通过改变指示剂的浓度,可实现对不同产品剩余货架信息的监测;根据其活化能值,可判断出该时间温度指示剂可指示的产品活化能范围为12~61 k J/mol。     

2,4-己二炔-1,6-二乙基脲的合成及聚合反应

研究了一种时间-温度指示剂2,4-己二炔-1,6-二乙基脲的合成方法,用元素分析、飞行时间质谱、傅立叶变换红外光谱、激光拉曼光谱和核磁共振对其结构进行了表征,并采用光密度计、红外光谱和紫外光谱对其聚合过程进行了初步研究。结果表明,该化合物在紫外灯照射和加热两种条件下,均可以发生固相聚合反应,但在紫外灯照射下的聚合速率要比加热条件下快得多。随着聚合程度的增加,化合物的颜色逐渐由白色变为蓝色甚至黑色,并具有时间累积效应,可以作为时间-温度指示剂使用。     

用于疫苗温度标签的共轭二乙炔类单体

目的 疫苗在生产运输过程中受到温度、辐射等因素会影响其效价，共轭二乙炔类疫苗温度标签能够将这些影响因素与疫苗稳定性紧密联系起来，进一步促进其在疫苗温度标签中的应用提供参考和理论借鉴。方法 首先对共轭二乙炔类单体的固相聚合机理和可发生固相聚合的单体结构进行简单分类和归纳，其次对可引起共轭二乙炔类单体聚合速率改变的因素进行总结，然后将共轭二乙炔类单体作为疫苗温度标签的研究现状和应用情况进行概述，最后对我国应用共轭二乙炔类疫苗温度标签存在的问题和未来发展方向进行分析和展望。结果 挑选聚合中能有明显变色的共轭二乙炔类单体，以及添加不同种类的自由基引发剂，以调节共轭二乙炔单体的聚合速率，来匹配不同产品的保质期以及运输需求。结论 共轭二乙炔类疫苗温度标签能够更好地指示疫苗的有效性，也可大大减少我国疫苗出口成本。     

非过渡金属催化芳香二炔和二硅烷基苯制备聚(硅苯-芳炔)树脂

以芳香基双炔和1,4-二(二甲基硅烷基)苯为原料,乙二醇二甲醚(DME)为溶剂,NaO H为催化剂,空气氛围下,一步反应制备得到含硅芳炔树脂(SPAR).并进一步探讨了催化剂、反应溶剂、温度、时间对聚合反应的影响.通过凝胶渗透色谱(GPC)、红外光谱、核磁分析确定产物的分子量和化学结构.实验结果表明:使用20 mol％...     

脲二酮的开环及氨酯化反应

用在线红外光谱跟踪1,3-双(3-氨基甲酸甲酯基-4-甲基苯基)脲二酮的开环反应,研究了温度、催化剂等对脲二酮开环反应的影响;同时,进行了脲二酮开环-氨酯化反应,用核磁共振(NMR)表征了产物甲苯-二(2-甲基-4-乙基)氨基甲酸酯的结构。结果表明,温度为80℃、催化剂三正丁基膦用量为m(cat)/m(uretedione)=4/100时,脲二酮开环反应比较完全;在三正丁基膦的催化下,可能会发生异氰酸酯三聚反应,导致异氰酸酯基浓度呈现先增大后减小的变化规律。此外,与乙醇反应时,脲二酮的开环、氨酯化同时进行,氨酯化速率大于开环速率,使产物具有规整的结构。     

5,7-二氨基-4,6-二硝基苯并氧化呋咱的制备

研究了5,7-二氨基-4,6-二硝基苯并氧化呋咱(DADNBF)的合成与精制。以邻硝基苯胺为起始原料,经氧化、硝化、VNS胺化3步反应得到5,7-二氨基-4,6-二硝基苯并氧化呋咱,3步总收率46%,讨论了硝化反应和VNS胺化反应的影响因素,确定了合成DADNBF的最佳反应条件:适宜硝化温度为30℃,VNS胺化反应时间为3h,酸化使用盐酸的浓度为1 mol/L。设计了由DADNBF钾盐重结晶,再酸化制备DADNBF的精制工艺,研究了重结晶溶剂对DADNBF钾盐收率和纯度的影响,确定水为最佳溶剂,重结晶产率为92%,酸化后DADNBF的纯度≥98.8%。采用核磁共振、红外光谱、质谱对目标化合物的结构进行了表征。     

碳酸乙二酯与二醇反应制备聚碳酸酯二元醇

以碳酸乙二酯、1,4-丁二醇和1,6-己二醇为原料,醋酸锌、硝酸锌为催化剂,考察了反应温度、反应时间等条件对碳酸乙二酯与二元醇反应的影响,制备出结构规整的以β-羟乙基、ω-羟烷氧基为端基的聚碳酸酯二元醇。产物经核磁共振波谱表征,1,4-丁二醇反应的聚碳酸酯二元醇的数均分子量为300-560,产物中由脱羰基反应形成的醚键链段含量可小于3%,1,6-己二醇反应的聚碳酸酯二元醇的数均分子量为700-980,产物中醚键链段含量可降低至0.24%。最后探讨了碳酸乙二酯与二元醇的反应机理。     

3,4-二硝基吡唑合成放大工艺研究

以吡唑为原料,经N-硝化、热重排、C-硝化等反应合成了3,4-二硝基吡唑(DNP)。进行了DNP的放大工艺研究,优化了硝化工艺条件,考察了C-硝化的工艺稳定性及重结晶溶剂苯甲腈的循环利用。研究发现:DNP较佳反应温度为55~57℃,反应时间45 min,收率86. 8%; DNP的放大硝化工艺具有较好的稳定性,重结晶溶剂可以循环利用5次以上,重结晶纯度99%以上。该放大合成工艺得到的DNP具有良好的物理化学性能,有望应用于混合炸药的研制。     

非过渡金属催化芳香二炔和二硅烷基苯制备聚(硅苯-芳炔)树脂（英文）

以芳香基双炔和1,4-二(二甲基硅烷基)苯为原料,乙二醇二甲醚(DME)为溶剂,NaOH为催化剂,空气氛围下,一步反应制备得到含硅芳炔树脂(SPAR)。并进一步探讨了催化剂、反应溶剂、温度、时间对聚合反应的影响。通过凝胶渗透色谱(GPC)、红外光谱、核磁分析确定产物的分子量和化学结构。实验结果表明:使用20mol%的NaOH为催化剂,单体比例为1∶1,在1mol/L的DME溶剂中,80℃反应12h得到最好的聚合效果。该聚合方法简单、价廉,无需复杂的后处理,且得到的产物具有较好的热稳定性。     

基于RAFT过程的N-(4-羧基苯基)马来酰亚胺和苯乙烯可控自由基共聚合

采用N-(4-羧基苯基)马来酰亚胺为单体,四氢呋喃做溶剂,偶氮二异丁腈为引发剂,以RAFT试剂二硫代苯甲酸苄酯为链转移剂,成功地进行了N-(4-羧基苯基)马来酰亚胺和苯乙烯的共聚合反应。结果表明,得到的聚合物数均分子量随单体转化率增加而呈线性增加,且聚合物的分子量分布小于1.5,二硫代苯甲酸苄酯显示出对聚合反应的良好控制作用。通过不同反应温度的聚合反应动力学得到共聚合反应的表观活化能为1.39 kJ/mol。     

果蔬泡沫网套中荧光增白剂及有机偶氮颜料筛查及迁移特征

目的 研究果蔬泡沫网套中风险因子的迁移情况,以期为果蔬泡沫网套的安全监管提出建议.方法 选用市售的果蔬泡沫网套进行荧光增白剂及有机偶氮颜料筛查,筛查出的风险因子在体积分数为4％的乙酸、体积分数为95％的乙醇及异丙醇模拟物中进行模拟迁移实验.结果 果蔬泡沫网套中含有荧光增白剂4,4-双(2-苯并恶唑基)二苯乙烯(OB-1),未检出有机偶氮;模拟迁移实验表明荧光增白剂OB-1能迁移至体积分数为95％的乙醇和异丙醇模拟物中.结论 果蔬泡沫网套中荧光增白剂OB-1易迁移至非酸性物质或者油性物质中,对人体健康可能存在潜在威胁.     

双酚S迁移量的快速检测及迁移规律研究

目的研究聚醚砜中双酚S迁移量的快速检测方法,以及双酚S的迁移规律。方法以液相色谱-质谱法(LC-MS)快速测定模拟液乙醇(体积分数为50%)、乙酸(质量浓度为30 g/L)及水中双酚S的迁移量,并以此为基础,研究不同的介质、温度、时间、厚度等因素对双酚S迁移规律的影响。结果该法对双酚S的检出限为2.0μg/L,定量限为6.0μg/L,在模拟液水、乙醇(体积分数为50%)、乙酸(质量浓度为30 g/L)中的加标回收率分别为95.2%~102%,97.3%~102%,96.3%~102%,相对标准偏差分别为2.6%~4.2%,2.6%~4.0%,3.3%~4.7%;在相同条件下,双酚S在乙醇(体积分数为50%)中的迁移量最大,其迁移量顺序为乙醇(50%)乙酸(30 g/L)水,同时符合温度越高则迁移量越大、厚度越大迁移量越高的规律。结论采用液相色谱-质谱法检测双酚S,具有操作简便、灵敏度高、重复性好、结果准确等特点;食品模拟物的属性是影响双酚S迁移行为的重要因素,同时,温度和厚度也影响着双酚S在PES中的迁移。     

Simultaneous flame ionization and absorbance detection of volatile and nonvolatile compounds by reversed-phase liquid chromatography with a water mobile phase

A flame ionization detector (FID) is used to detect volatile organic compounds that have been separated by water-only reversed-phase liquid chromatography (WRP-LC). The mobile phase is 100% water at room temperature, without use of organic solvent modifiers. An interface between the LC and detector is presented, whereby a helium stream samples the vapor of volatile components from individual drops of the LC eluent, and the vapor-enriched gas stream is sent to the FID. The design of the drop headspace cell is simple because the water-only nature of the LC separation obviates the need to do any organic solvent removal prior to gas phase detection. Despite the absence of organic modifier, hydrophobic compounds can be separated in a reasonable time due to the low phase volume ratio of the WRP-LC columns. The drop headspace interface easily handles LC flows of 1 mL/min, and, in fact, compound detection limits are improved at faster liquid flow rates. The transfer efficiency of the headspace interface was estimated at 10% for toluene in water at 1 mL/min but varies depending on the volatility of each analyte. The detection system is linear over more than 5 orders of 1-butanol concentration in water and is able to detect sub-ppb amounts of o-xylene and other aromatic compounds in water. In order to analyze volatile and nonvolatile analytes simultaneously, the FID is coupled in series to a WRP-LC system with UV absorbance detection. WRP-LC improves UV absorbance detection limits because the absence of organic modifier allows the detector to be operated in the short-wavelength UV region, where analytes generally have significantly larger molar absorptivities. The selectivity the headspace interface provides for flame ionization detection of volatiles is demonstrated with a separation of 1-butanol, 1,1,2-trichloroethane (TCE), and chlorobenzene in a mixture of benzoic acid in water. Despite coelution of butanol and TCE with the benzoate anion, the nonvolatile benzoate anion does not appear in the FID signal, allowing the analytes of interest to be readily detected. The complementary selectivity of UV-visible absorbance detection and this implementation of flame ionization detection allows for the analysis of volatile and nonvolatile components of complex samples using WRP-LC without the requirement that all the components of interest be fully resolved, thus simplifying the sample preparation and chromatographic requirements. This instrument should be applicable to routine automated water monitoring, in which repetitive injection of water samples onto a gas chromatograph is not recommended.     

含苯乙烯VOCs废气排放控制治理案例分析

介绍了高分子材料生产工厂含苯乙烯的挥发性有机化合物(VOCs)废气治理工程实例。生产废气通过集中收集,根据实际情况设计排风量,经过炭床分子过滤器处理后高空排放。废气处理系统的VOCs治理效率高达98.8%;气相色谱质谱联用仪检测发现废气中含量最高的物种为苯乙烯,达67.5%-77.2%,苯乙烯排放量远低于国家排放标准,VOCs减排效果好,环境效益明显。采用炭床分子过滤器对VOCs排放控制具有推广价值。     

金属罐外涂膜中苯和甲苯向内涂膜迁移的影响因素研究

目的 采用高效液相色谱法分析金属罐外壁涂膜中苯和甲苯向内涂膜的迁移规律与影响因素。方法 将食品罐印铁在不同堆码温度、 湿度和压强条件下堆码储放2个月后, 采用体积分数为10%的乙醇模拟液萃取试样内壁涂膜中的苯和甲苯, 并利用正交试验优化得到迁移率最小的贮藏条件。结果未经堆码的金属印铁内涂中未检测到苯和甲苯, 而堆码后的试样内涂中均检出了一定量的苯和甲苯。结论 堆码温度对迁移实验结果的影响比较显著。     

腰果壳油基超交联聚合物的制备及吸附VOCs性能EI北大核心

以农业副产物腰果壳油为原料,通过外交联法和溶剂交联法分别制备超交联聚合物(HCPs)吸附剂F-HCP和C-HCP,并对其吸附挥发性有机化合物(VOCs)性能进行研究。采用红外光谱(FTIR)、热重分析(TGA)、N2吸-脱附法和扫描电子显微镜(SEM)等方法对制备的吸附剂进行表征,以静态吸附法考察两种超交联聚合物对六种VOCs的吸附性能,以邻二甲苯为典型VOC进行动态吸附,探讨进气浓度对吸附能力的影响。结果表明:相较于C-HCP,F-HCP显示出较高的静态吸附性能,其对邻二甲苯、甲苯、环己烷、正己烷、丁酮、丙酮的静态吸附量分别为930,801,300,214,203,164 mg·g^(-1);在进气浓度为2171 mg·m^(-3)时,F-HCP和C-HCP对邻二甲苯的动态吸附量分别为149 mg·g^(-1)和146 mg·g^(-1),平衡吸附量随进气浓度的增加而增大。循环再生吸附实验表明,C-HCP 5次循环吸附后的吸附量为首次吸附量的93.9%。     

食品接触材料PVC中32种增塑剂在4种食品模拟物中的迁移规律研究

在不同的条件下,将含有已知量增塑剂的PVC薄膜,在水、乙酸(体积分数为3%)、乙醇(体积分数10%)和橄榄油等4种食品模拟物中浸泡,在规定的时间点抽取一定量的浸泡液,采用气相色谱-质谱法测定增塑剂含量,研究迁移量及迁移率与时间、温度、模拟食品属性、增塑剂初始浓度及包装材料厚度等参数的关系。结果表明:食品模拟物的食品属性对增塑剂的迁移行为有显著影响;增塑剂溶出种类数、迁移量和迁移率随温度升高显著增加;薄膜厚度增加,则增塑剂迁移量大,迁移率降低;薄膜中增塑剂初始浓度高,则迁移量大,迁移率低。     

Performance of a reactor containing denitrifying immobilized biomass in removing ethanol and aromatic hydrocarbons (BTEX) in a short operating period

A horizontal-flow anaerobic immobilized biomass reactor (HAIB) containing denitrifying biomass was evaluated with respect to its ability to remove, separately and in a short operating period (30 days), organic matter, nitrate, and the hydrocarbons benzene (41.4 mg L-1), toluene (27.8 mg L-1), ethylbenzene (31.1 mg L-1), o-xylene (28.5 mg L-1), m-xylene (28.4 mg L-1) and p-xylene (32.1 mg L-1). The purified culture, which was grown in the presence of the specific hydrocarbon, was used as the source of cells to be immobilized in the polyurethane foam. After 30 days of operation, the foam was removed and a new immobilized biomass was grown in the presence of another hydrocarbon. The average hydrocarbon removal efficiency attained was 97%. The organic matter, especially ethanol, was removed with an average efficiency of 83% at a mean influent concentration of 1185.0 mg L-1. A concomitant removal of 97% of nitrate was observed for a mean influent concentration of 423.4 mg L-1. The independent removal of each hydrocarbon demonstrated that these contaminants can be biodegraded separately, without the need for a compound to be the primary substrate for the degradation of another. This study proposes the application of the system for treatment of areas contaminated with these compounds, with substitution and formation of a biofilm in a 30-day period.     

Remote detection of volatile organic compounds by passive multispectral infrared imaging measurements

Automated pattern recognition methodology is described for the detection of signatures of volatile organic compounds from passive multispectral infrared imaging data collected from an aircraft platform. Data are acquired in an across-track scanning mode with a downward-looking line scanner based on 8 to 16 spectral channels in the 8-14 and 3-5 microm spectral ranges. Two controlled release experiments are performed in which plumes of ethanol are generated and detected from aircraft overflights at altitudes of 2200 to 2800 ft (671 to 853 m). In addition, a methanol release from a chemical manufacturing facility is monitored. Automated classifiers are developed by application of piecewise linear discriminant analysis to the calibrated, registered, and preprocessed radiance data acquired by the line scanner. Preprocessing steps evaluated include contrast enhancement, temperature-emissivity separation, feature selection, and feature extraction/noise reduction by the minimum noise fraction (MNF) transform. Successful classifiers are developed for both compounds and are tested with data not used in the classifier development. Separation of temperature and emissivity by use of the alpha residual calculation is found to reduce false positive detections to a negligible level, and the MNF transform is shown to enhance detection sensitivity.     

Analysis of a GC/MS thermal desorption system with simultaneous sniffing for determination of off-odor compounds and VOCs in fumes formed during extrusion coating of low-density polyethylene

A thermal desorption equipment introducing volatile organic compounds (VOCs) into the gas chromatographic/ mass spectrometric system (GC/MS) with simultaneous sniffing (SNIFF) is a suitable method for identifying the volatile organic off-odor compounds formed during the extrusion coating process of low-density polyethylene. Fumes emitted during the extrusion coating process of three different plastic materials were collected at two different temperatures (285 and 315 degrees C) from an outgoing pipe and near an extruder. The VOCs of fumes were analyzed by drawing a known volume of air through the adsorbent tube filled with a solid adsorbent (Tenax GR). The air samples were analyzed by using a special thermal desorption device and GC/MS determination. The simultaneous sniffing was carried out to detect off-odors and to assist in the identification of those compounds that contribute to tainting and smelling. The amounts of off-odor carbonyl compounds and the total content of the volatile organic compounds were determined. The most odorous compounds were identified as carboxylic acids while the majority of the volatile compounds were hydrocarbons. The detection and quantification of carboxylic acids were based on the characteristic ions of their mass spectra. The higher the extrusion temperature the more odors were detected. An important observation was that the total concentration of volatiles was dependent not only on the extrusion temperature but also on the plastic material.