摘要
对中低温煤焦油的综合高效利用有助于提高煤炭作为化工原料的综合利用效能,因而利用联用技术对典型中低温煤焦油重质馏分进行分子表征,可为其后续高效的加工利用提供数据支撑。利用电喷雾电离源(ESI)和大气压光致电离源(APPI)结合傅里叶变换离子回旋共振质谱仪(FT-ICRMS)在分子水平上表征影响典型中低温煤焦油重质馏分加工利用方式的含氮化合物、含氧化合物以及芳烃化合物,探讨含氮和含氧化合物、芳烃类化合物的组成和碳数分布。结果表明,采用正离子电喷雾(+ESI)结合FT-ICRMS共鉴定出N1、N2、N1O1、N1O2、N1O3、N2O1、N2O2、N1O1S1共8种不同分子组成的碱性氮化物;采用负离子(-ESI)模式下FT-ICRMS检测出N1、N2、N1O1、N1O2、N1O3、N2O1、N1O1S1共7类非碱性氮化物,检测出O1、O1S1、O2、O2S1、O3、O4共6类酸性氧化物;采用APPI正离子模式结合FT-ICRMS检测出4167种芳烃化合物,其中碱性氮化物相对丰度较高的为N1、N1O1类化合物,而非碱性氮化物相对丰度较高的为N1O1、N1O2类化合物,O1、O2、O3类酸性氧化物具有较高的相对丰度。依据各化合物的等效双键数和碳数分布可推测其分子组成,N1类碱性氮化物母核结构主要为喹啉、吖啶、菲啶、二苯并喹啉和苯并吖啶等2~4环的多芳环结构;N1O1类碱性氮化物的主要母核结构为苯并喹啉、吖啶、菲啶、二苯并喹啉、苯并吖啶、二苯并吖啶同时并有呋喃、氧芴等结构;N1O1、N1O2类非碱性氮化物与碱性氮化物相比,其侧链相对较短,其母核结构为吡咯、吲哚、咔唑并环氧烷、呋喃以及部分苯环结构,氧以羟基、醚基、羰基或酰基形式存在;O1类酸性氧化物种类较多,母核结构主要为萘酚、蒽酚、菲酚、苯并蒽酚、苯并萘酚,还有少量的芘酚;O2类酸性氧化物的种类较少,母核结构主要为萘二酚、蒽二酚、菲二酚,同时也存在羧基官能团的长链烷烃。O3类酸性氧化物的种类介于O1类和O2类之间,母核结构有可能为萘二酚并呋喃、蒽二酚、菲二酚,烷基侧链中含有羟基、醚键或羧基等结构;芳烃化合物主要为烷基侧链较长的2~3环稠环芳烃。
Abstract
The comprehensive and efficient utilization of medium and low temperature coal tar helped to improve thecomprehensive utilization efficiency of coal as a chemical raw material. The compound composition and molecularcharacterization of the heavy fraction of medium and low temperature coal tar were important data foundations for theefficient processing and utilization of medium and low temperature coal tar. The nitrogen compounds, oxygen com⁃pounds and aromatic compounds that affect the processing and utilization of heavy components of typical medium⁃lowtemperature coal tar were characterized at molecular level by electrospray ionization source ( ESI) and atmosphericpressure photoionization source (APPI) combined with Fourier transform ion cyclotron resonance mass spectrometer(FT⁃ICR MS). On this basis, the composition and distribution of the above types of compounds were analyzed. Theresults showed that eight kinds of basic nitrides with different molecular compositions such as N1、 N2、 N1O1、 N1O2、N1O3、 N2O1、 N2O2、 N1O1S1had been identified by positive ion electrospray (ESI) combined with FT-ICR MS.Seven types of non⁃basic nitrides including N1、 N2、 N1O1、 N1O2、 N1O3、 N2O1、 N1O1S1, were detected by FT-ICR MS with negative ion ESI mode, while six types of acid oxides including O1、 O1S1、 O2、 O2S1、 O3、 O4 weredetected. 4 167 aromatic compounds were detected in the positive ion mode of APPI combined with FT-ICR MS.Among them, the basic nitrides of N1 and N1O1 had higher relative abundance, the higher relative abundance of non⁃basic nitrides were N1O1 and N1O2 compounds, and the higher relative abundance of acid oxides were O1, O2 and O3compounds. According to the equivalent double bond number (DBE) and carbon number distribution of the maincompounds, the molecular composition of N1 basic nitrides could be inferred. The main nuclear structure of N1 basicnitrides were polyaromatic ring with 2-4 rings, including quinoline, acridine, phenanthidine, dibenzoquinoline andbenzobaadine. The main parent nucleus structures of N1O1 alkaline nitrides were benzoquinoline, acridine, phenan⁃thridine, dibenzoquinoline, benzoacridine, and dibenzacridine, which were combined with furan, oxyfluorene,and other structures. Compared with basic nitrides, N1 O1 and N1 O2 non basic nitrides had relatively short sidechains, and their parent nucleus structures were pyrrole, indole, carbazoepoxane, furan, and some benzene ringstructures. Oxygen exists in the form of hydroxyl, ether, carbonyl, or acyl groups. There were many types of O1acidic oxides, and the parent nucleus structure was mainly composed of naphthol, anthracene, phenanthrene,benzo anthracene, benzo naphthol, and a small amount of pyrene phenol. There were fewer types of O2 type acidicoxides, and the parent nucleus structure was mainly composed of naphthalene, anthracene, and phenanthrene, aswell as long⁃chain alkanes with carboxyl functional groups. The number of types of O3 type acidic oxides was betweenO1 and O2 types, and the parent nucleus structure might be naphthalene diphenyl furan, anthracene diphenyl, andphenanthrene diphenyl. The alkyl side chain contained structures such as hydroxyl, ether bonds, or carboxyl groups.Aromatic compounds were mainly 2-3 ring polycyclic aromatic hydrocarbons with longer alkyl side chains.