阻燃高抗冲聚苯乙烯热降解研究

利用热失重-红外联用仪(TGA-IR)分析了高抗冲聚苯乙烯(HIPS)的热降解过程,结合热裂解气相色谱-质谱联用仪(Py-GC/MS)分析了HIPS的热裂解产物,利用化学方程式阐述了HIPS自由基降解反应.对十溴二苯乙烷、三氧化二锑复配阻燃体系的热降解过程进行了研究,讨论了阻燃HIPS的凝聚相阻燃、气相阻燃机理.实验表明,HIPS燃烧时主要发生β-断裂,大量烟雾主要由苯乙烯、甲苯、α-甲基苯乙烯、苯乙烷、丁二烯等组成,其中凝聚相主要是1,3,5-三苯基苯乙烯及其他部分低聚物.在不同的温度下,阻燃HIPS的热裂解产物不同,在较高的温度下,小分子化合物明显增多.     

在线热裂解/气相色谱-质谱分析3-吡啶甲酸茴香酯的热裂解产物

采用在线热裂解/气相色谱-质谱(Py/GC-MS)联用技术对3-吡啶甲酸茴香酯进行热裂解分析。通过酰氯化和酯化反应合成了新型目标化合物3-吡啶甲酸茴香酯,其分子式为C14H14NO3。目标化合物的结构经核磁氢谱(1H NMR)、核磁碳谱(13C NMR)、红外光谱(IR)和高分辨质谱(HRMS)进行确证,并通过热重-微热重-差示扫描量热(TG-DTG-DSC)分析方法对目标化合物的热稳定性进行分析。在空气氛围中,将目标化合物分别于300,600,900℃下进行热裂解,并通过气相色谱-质谱法对其挥发性热裂解产物进行定性和半定量分析。研究显示:目标化合物共经历了两次失重过程。第一次失重在129.9~158.9℃之间,失重2.3%;第二次失重在158.9~274.9℃之间,失重达90.1%,230.1℃时失重率最大。热裂解共产生44种产物,包括具有香味特征的大茴香醛、对甲基苯酚、松油醇、D-香茅醇、大茴香醚和茴香醚等化合物。其中裂解温度对裂解产物的种类和相对含量具有明显影响。300℃时α-二去氢菖蒲烯的相对含量最高,600,900℃时,相对含量最高的分别是大茴香醛和对甲基苯酚。苯甲醛、茴香醚和大茴香醚的相对含量随着温度的升高呈先增加后降低趋势;而对甲基苯酚含量则随着温度的升高而增加。根据主要裂解产物及其相对含量的变化,对目标化合物的裂解机理进行了初步探讨。     

废弃印刷电路板材料裂解产物的高分辨裂解气相色谱-质谱分析

采用高分辨裂解气相色谱-质谱法(PyGC-MS)分析了FR-4型印刷电路板粉末样品的裂解产物。在氦气氛围中,分别在350,450,550,650和750 ℃下对印刷电路板粉末样品进行热裂解,并通过毛细管气相色谱-质谱对裂解产物进行分析,研究了不同裂解温度下裂解产物分布以及主要裂解产物的产率与裂解温度的关系,根据热分解产物的组成,探讨了热分解反应机理。     

β-甲基萘长链烷基化产物的气相色谱-质谱分析

采用气相色谱—质谱联用(GC—MS)技术，基于优化的色谱分析条件对β-甲基萘长链烷基化产物的组成及其含量进行分析；产物得到了很好的分离，共分离出48个峰，用面积归一化法测定其相对含量，采用气相色谱—质谱法对组分进行了表征；结果表明，甲基萘烷基化反应产物非常复杂，除目标产物己基甲基萘、二己基甲基萘外，还存在己基甲基四氢萘、己基萘、己基多甲基萘等副产物；本文建立一种便捷、可靠的甲基萘长链烷基化工艺评价手段，为反应条件的优化、反应机理的探讨及新型催化体系的研究和开发创造了条件。     

不同氛围下绿原酸的热解行为及其裂解产物中苯酚含量分布规律研究

采用热重分析法(TGA)及在线裂解气相色谱-质谱联用仪(Py/GC - MS)研究了烟草中绿原酸在不同氛围下的热解行为及其含量分布规律.先用TGA确定了绿原酸在氮气氛围中的主要热失重区间,选取4个典型的温度点,再结合卷烟在高温燃烧区的3个温度点,分别在惰性(氦气)和有氧(含9％氧气的氮氧混合气)氛围中进行热裂解实验,对...     

麻浆卷烟纸热裂解产物的气相色谱/质谱分析

采用热失重(TG)和裂解气相色谱/质谱法(PyGC/MS)研究了麻浆卷烟纸的热裂解行为.在He气气氛围中,将麻浆卷烟纸分别在400、500、600、700、800和900℃下进行热裂解,并以GC/MS对其裂解产物进行定性和半定量分析.结果表明,不同的裂解温度直接影响生成产物的类型和相对含量.麻浆卷烟纸可裂解出1-甲基-1,3-环戊二烯、2-甲基呋喃、2,3-二氢香豆酮、苯和甲苯等156种产物.低温下,裂解产物主要为烯类、呋喃类和酮类化合物;随着裂解温度的增加,烯、酮类的含量下降,苯及其衍生物和稠环芳烃的含量逐渐增加.可通过降低卷烟燃烧温度来降低卷烟纸裂解产生的有害成分含量.如果单纯考虑麻浆卷烟纸的影响,卷烟的最佳燃烧温度应控制在500℃左右.     

Py/GC-MS对烯烃装置堵塔物组成的分析

燕山石油化工股份有限公司合成橡胶事业部,北京 102500)气相色谱一质谱联用技术在有机物的分析中发挥着非常重要的作用,但其局限在于只能测定可以汽化的且相对分子质量较小的化合物,对相对分子质量大的化合物则无能为力.裂解/色谱一质谱(Py/GC-MS)联用则解决了这个问题,使微量的相对分子质量大的样品在选择好的易控制的条件下被快速加热,迅速生成许多可挥发的裂解产物即裂解碎片,将裂解碎片导入色谱-质谱联用仪分离鉴定,最后根据裂解碎片的特征来判断样品的组成和性质.     

裂解气相色谱-质谱法研究壬酸香草酰胺的热裂解

采用在线热裂解/气相色谱-质谱联用技术(Py/GC-MS)对壬酸香草酰胺(PAVA)的热裂解行为进行了研究,在氦气氛围中考察了不同裂解温度和裂解时间对PAVA裂解的影响,通过GC-MS对裂解产物进行定性和半定量分析。结果表明,随着裂解温度的升高,PAVA裂解率快速提高,裂解产物也进一步增多,当裂解温度达到700℃以上时,可裂解出壬酰胺、2-甲氧基-4-甲基苯酚、1-己烯、壬基腈、壬醛等14种产物。同一温度下随着裂解时间的延长,PAVA的裂解率逐步升高,裂解产物发生了进一步的裂解。根据热裂解产物及主要裂解产物的含量变化,初步推断了PAVA的裂解规律。     

热分析-傅里叶变换红外光谱-气相色谱-质谱联用测定葡萄糖的热分解产物

应用热分析-傅里叶变换红外光谱-气相色谱-质谱联用测定葡萄糖的热分解产物。葡萄糖样品在同步热分析条件下,分别在氮气和氮氧混合气氛围中进行热解,同时进行红外扫描,根据样品的热重曲线和红外谱图进行判定和选择GC-MS温度点,裂解产物进入GC-MS进行分离和鉴定。结果表明:葡萄糖在220℃,300℃,350℃和470℃下的热分解产物中共检出44种化合物;葡萄糖在高温下的热裂解产物中共检出76种化合物。分析结果对葡萄糖在不同温度下的应用有较好的理论指导。     

新型潜香类化合物N-(2,3-吡嗪二甲酰基)-丙氨酸甲酯热裂解气相色谱-质谱分析

采用在线热裂解-气相色谱-质谱联用技术(Py-GC-MS)分析了潜香吡嗪类化合物N-(2,3-吡嗪二甲酰基)-丙氨酸甲酯的热裂解行为。首先通过对2,3-吡嗪二羧酸酰胺化反应合成了新型目标化合物N-(2,3-吡嗪二甲酰基)-丙氨酸甲酯,其结构经X射线单晶衍射(XRD),1H NMR,13C NMR,IR和HR-MS证实,然后在空气氛围中,对目标化合物分别在300,600,900℃下进行热裂解,并通过GC-MS对其挥发性热裂解产物进行定性和半定量分析。结果表明:1裂解形成了包括具有香味特征的吡嗪类、大茴香醇和大茴香醛在内的裂解产物共48种。不同温度下挥发性热裂解产物的类型和相对含量不同,300℃和600℃时相对含量最高的均为乙酸,而900℃时相对含量最高的为吡嗪,且与300℃和600℃裂解条件相比所形成的吡嗪类衍生物种类较多,相对含量较高。2在具有香味特征的裂解产物中,大茴香醇的相对含量随温度升高而升高,而大茴香醛和苯甲醛的相对含量则呈现随着温度升高而降低的趋势。基于目标化合物的热裂解产物的定性及定量变化情况,初步探讨了该物质可能的裂解机理。     

烤烟烟叶和烟梗的热裂解产物的研究

为了加深理解梗丝在卷烟叶组配方中的作用,对比研究了烤烟叶片和烟梗的化学组成以及它们在不同温度下的热裂解产物。一个改进后的热裂解装置被用来模拟卷烟的燃烧行为。采用热裂解仪研究了烤烟叶片和烟梗在大气环境中于300 ℃、600 ℃和900 ℃下的热裂解行为,并采用气相色谱-质谱联用仪对它们的热裂解产物进行分析。结果表明,烤烟烟叶和烟梗的热裂解产物种类随着热裂解温度的增加而增多;在相同热裂解温度条件下,烟叶的热裂解产物种类明显多于烟梗的热裂解产物。     

Py-GC/MS分析烟用添加剂黄芩浸膏的热裂解产物

采用在线热裂解气相色谱-质谱法(Py-GC/MS)法研究了黄芩浸膏热裂解行为。在氦气氛围中,将黄芩浸膏分别在300、450、600、750和900℃下进行热裂解,并以GC/MS对其裂解产物进行定性和半定量分析,并用黄芩浸膏进行了卷烟加香试验。结果表明:①黄芩浸膏在这一系列裂解温度下检测到的挥发性热裂解产物分别为12种、19种、40种、55种和46种;②黄芩浸膏低温区(300℃～450℃)裂解后产生大量醛类、酮类、酯类和呋喃类物质,这些物质是构成卷烟香味的重要物质,能改善卷烟吸味、减轻刺激性;③在高温区(750℃～900℃)产生大量的芳香族化合物,如苯、甲苯、乙苯、萘等。该研究为香味物质在卷烟燃烧过程中的挥发性物质提供了例证。     

在线裂解气相色谱/质谱联用法研究4-氧代-β-大马酮的热裂解行为

用在线裂解气相色谱/质谱法(PyGC/MS)研究了4-氧代-β-大马酮的热裂解行为。在氦气氛围中,将4-氧代-β-大马酮分别在350，450，550，650，700和750 ℃下进行热裂解,并以GC/MS对其裂解产物进行定性和半定量分析。结果表明,不同的裂解温度直接影响生成产物的类型和相对含量。4-氧代-β-大马酮可裂解出β-大马酮、4-氧代-β-紫罗兰酮、3,4,4-三甲基-环己-2-烯-1-酮和2,5,5-三甲基-环己-3-烯-1-酮等54种裂解产物。在550 ℃以下时,只有少量4-氧代-β-大马酮发生裂解; 在750 ℃时,几乎完全裂解,转移率达99.74%, 裂解产物达45种之多。随着裂解温度的升高,裂解产物越来越复杂,并出现有害物质如苯、甲苯、蒽和菲等。根据4-氧代-β-大马酮裂解产物相对含量的变化规律,对其裂解产物的形成机理进行了探讨,认为4-氧代-β-大马酮可能按照4种途径发生裂解。     

Pyrolysis and combustion of tobacco in a cigarette smoking simulator under air and nitrogen atmosphere

A coupling between a cigarette smoking simulator and a time-of-flight mass spectrometer was constructed to allow investigation of tobacco smoke formation under simulated burning conditions. The cigarette smoking simulator is designed to burn a sample in close approximation to the conditions experienced by a lit cigarette. The apparatus also permits conditions outside those of normal cigarette burning to be investigated for mechanistic understanding purposes. It allows control of parameters such as smouldering and puff temperatures, as well as combustion rate and puffing volume. In this study, the system enabled examination of the effects of “smoking” a cigarette under a nitrogen atmosphere. Time-of-flight mass spectrometry combined with a soft ionisation technique is expedient to analyse complex mixtures such as tobacco smoke with a high time resolution. The objective of the study was to separate pyrolysis from combustion processes to reveal the formation mechanism of several selected toxicants. A purposely designed adapter, with no measurable dead volume or memory effects, enables the analysis of pyrolysis and combustion gases from tobacco and tobacco products (e.g. 3R4F reference cigarette) with minimum aging. The combined system demonstrates clear distinctions between smoke composition found under air and nitrogen smoking atmospheres based on the corresponding mass spectra and visualisations using principal component analysis.     

Microprobe sampling—Photo ionization-time-of-flight mass spectrometry for in situ chemical analysis of pyrolysis and combustion gases: Examination of the thermo-chemical processes within a burning cigarette

A microprobe sampling device (μ-probe) has been developed for in situ on-line photo ionization mass spectrometric analysis of volatile chemical species formed within objects consisting of organic matter during thermal processing. With this approach the chemical signature occurring during heating, pyrolysis, combustion, roasting and charring of organic material within burning objects such as burning fuel particles (e.g., biomass or coal pieces), lit cigarettes or thermally processed food products (e.g., roasting of coffee beans) can be investigated. Due to its dynamic changes between combustion and pyrolysis phases the cigarette smoking process is particularly interesting and has been chosen as first application. For this investigation the tip of the μ-probe is inserted directly into the tobacco rod and volatile organic compounds from inside the burning cigarette are extracted and real-time analyzed as the glowing front (or coal) approaches and passes the μ-probe sampling position. The combination of micro-sampling with photo ionization time-of-flight mass spectrometry (PI-TOFMS) allows on-line intrapuff-resolved analysis of species formation inside a burning cigarette. Monitoring volatile smoke compounds during cigarette puffing and smoldering cycles in this way provides unparalleled insights into formation mechanisms and their time-dependent change. Using this technique the changes from pyrolysis conditions to combustion conditions inside the coal of a cigarette could be observed directly. A comparative analysis of species formation within a burning Kentucky 2R4F reference cigarette with μ-probe analysis reveals different patterns and behaviors for nicotine, and a range of semi-volatile aromatic and aliphatic species.     

沸石在去除卷烟烟气中亚硝胺的应用

吸烟污染;沸石;添加剂;沸石在去除卷烟烟气中亚硝胺的应用     

The pyrolysis of non-volatile tobacco ingredients using a system that simulates cigarette combustion conditions

This is the second part of a systematic study in which tobacco ingredients are pyrolysed using experimental conditions designed to simulate the average combustion conditions inside a burning cigarette. In the first part, the pyrolysis system was developed and single-substance, mostly semi-volatile tobacco ingredients were pyrolysed. It was predicted that on a cigarette, the majority of these semi-volatile ingredients would transfer to smoke with little pyrolysis.In this part of the study, a further 159 non-volatile and complex ingredients, as well as ingredient mixtures, have been pyrolysed and the pyrolysis products determined using a gas chromatography–mass spectrometric system coupled to the pyrolyser. These non-volatile tobacco ingredients generally decomposed completely in the pyrolysis system, often yielding many products in relatively small amounts. The study has concentrated on the biologically active substances produced by pyrolysis, in particular the “Hoffmann analytes”. These analytes are believed by regulatory authorities in Canada and U.S.A. to be relevant to smoking-related diseases. They are based on lists published by Hoffmann and co-workers of the American Health Foundation in New York. For the pyrolysis of many of the non-volatile ingredients, no “Hoffmann analytes” were detected amongst the products. When they were occasionally formed, they included phenols, benzene, toluene, styrene and furfural (furfural is biologically active but it does not appear on any of the Hoffmann or regulatory authority lists). Those ingredients that did yield such products generally produced them in relatively small quantities although furfural was produced in relatively large quantities by pyrolysis of some ingredients, especially sugars. Those ingredients that produced biologically active constituents during their pyrolysis have been further assessed. This was done by adding them to cigarettes, machine-smoking the cigarette and comparing their smoke yields to those from a control (no ingredient) cigarette. From this comparison, it was found that in general the ingredients added to cigarettes do not increase the smoke components relative to the control cigarette. The pyrolysis technique of the present study tends to over-predict the amount of decomposition that the non-volatile ingredients undergo relative to their behaviour in a burning cigarette. Several examples are discussed, in particular ingredients that produce furfural during pyrolysis.This general pyrolysis technique is thus a first step in the total toxicological assessment of tobacco ingredients and is a useful screening tool for indicating which ingredients may yield biologically active products during decomposition of the ingredients. There are, however, some products such as formaldehyde and the carbon oxides that are not detected by the pyrolyser-gas chromatography–mass spectrometric technique employed here. The generation and detection of these products during the pyrolysis of selected tobacco ingredients is the subject of a parallel paper.     

新型潜香化合物3,6-二甲基-2,5-吡嗪二甲酸二薄荷醇酯的热裂解产物

为开发新型高温释放型烟用香料,以2,3,5,6-四甲基吡嗪和薄荷醇为原料,经过酯化反应制备了3,6-二甲基-2,5-吡嗪二甲酸二薄荷醇酯(DPAME)。采用在线热裂解-气相色谱-质谱联用技术(Py-GC-MS)在空气氛围和不同的温度(300、600和900℃)下,对DPAME进行热裂解研究,裂解产物经GC-MS进行了定性和半定量分析。结果表明,DPAME在300℃下裂解产生了多种有致香效果的醛类、薄荷烯和薄荷醇等;在600℃和900℃下裂解产生了烯烃类、烷基吡嗪、薄荷醇和薄荷烯等香味物质,并且吡嗪类的种类和相对含量在这两个温度下明显增加。结合DPAME的热裂解产物分析和卷烟感官评吸结果,初步推测了其可能的裂解机理。采用该方法可以方便、快速地分离鉴定物质的热裂解产物,为该物质在烟草中的加香应用提供理论依据。     

The important role of quinic acid in the formation of phenolic compounds from pyrolysis of chlorogenic acid

Chlorogenic acid and its two structural components, quinic acid and caffeic acid, were pyrolyzed under reaction conditions simulating the typical pyrolysis conditions inside a burning cigarette. Major phenolic products from pyrolysis of the three acids were quantified and compared to evaluate the respective contribution of the quinic and caffeic acid moieties to the overall phenolic yield in chlorogenic acid pyrolysis. The results show that the most prominent phenolic product of chlorogenic acid is catechol, followed in order by phenol, hydroquinone, and alkylcatechols. Among these phenolics, catechol and alkylcatechols are formed mainly from the caffeic acid moiety of chlorogenic acid, while phenol and hydroquinone are produced predominantly from the quinic acid moiety. The quinic acid moiety can thus contribute more than 40 % of the overall phenolic yields in chlorogenic acid pyrolysis (0.54 mol mol^?1 chlorogenic acid pyrolyzed at 600 °C). Because considerable amounts of free quinic acid and its derivatives exist in tobacco, the results of this study indicate that quinic acid can be an important source of phenolic compounds, especially hydroquinone and phenol, in tobacco smoke.     

Puff-by-puff resolved characterisation of cigarette mainstream smoke by single photon ionisation (SPI)-time-of-flight mass spectrometry (TOFMS): comparison of the 2R4F research cigarette and pure Burley, Virginia, Oriental and Maryland tobacco cigarettes

Soft single photon ionisation (SPI)-time-of-flight mass spectrometry (TOFMS) is applied for the characterisation and comparison of puff-by-puff resolved and total yields of cigarette mainstream smoke from single tobacco type cigarettes (Virginia, Oriental, Burley, and Maryland) and the 2R4F University of Kentucky research cigarette. Puff-by-puff characteristics of various smoke components within one cigarette type as well as between different cigarette types can differ tremendously. This is demonstrated by means of a few selected compounds. Puff yields vary between 15 and 106 μm for acetaldehyde, 6 and 57 μm for NO, and between 1 and 8 μm for butadiene. Thereby, cigarettes containing 100% Oriental and Burley tobacco exhibit a very unique behaviour for the first and last puff. Different cultivation and processing methods as well as burning characteristics are most likely responsible for this. Since the 2R4F cigarette contains all four tobacco types it combines features of all of them. However, for some smoke constituents, smoking of the 2R4F reference cigarette results in exceptionally high yields which might not be attributable to the four pure tobacco types, but to other factors. In addition, comparison of the different cigarettes was also carried out by normalising the yields to puff resolved particulate matter. This procedure minimises effects caused by unequal smoke formation and represents another approach in evaluating the data.