Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland; Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
University of Hohenheim, Institute of Food Chemistry (170b), Garbenstrasse 28, 70599, Stuttgart, Germany.
Chemosphere. 2022 Mar;291(Pt 2):132938. doi: 10.1016/j.chemosphere.2021.132938. Epub 2021 Nov 16.
Technical chlorinated paraffins (CPs) are produced via radical chlorination of n-alkane feedstocks with different carbon chain-lengths (∼C-C). Short-chain CPs (SCCPs, C-C) are classified as persistent organic pollutants (POPs) under the Stockholm Convention. This regulation has induced a shift to use longer-chain CPs as substitutes. Consequently, medium-chain (MCCPs, C-C) and long-chain (LCCPs, C) CPs have become dominant homologues in recent environmental samples. However, no suitable LCCP-standard materials are available. Herein, we report on the chemical synthesis of single-chain C-CP-materials, starting with a pure n-alkane and sulfuryl chloride (SOCl). Fractionation of the crude product by normal-phase liquid-chromatography and pooling of suitable fractions yielded in four C-CP-materials with different chlorination degrees (m = 39-52%). In addition, polar side-products, tentatively identified as sulfite-, sulfate- and bis-sulfate-diesters, were separated from CPs. The new single-chain materials were characterized by LC-MS, H-NMR and EA. LC-MS provided Relative retention times for different C-CP homologues and side-products. Mathematical deconvolution of full-scan mass spectra revealed the presence of chloroparaffins (57-93%) and chloroolefins (COs, 7-26%) in the four single-chain C-CP-materials. Homologue distributions and chlorination degrees were deduced for CPs and COs. H-NMR revealed chemical shift ranges of mono-chlorinated (δ = 3.2-5.3 ppm) and non-chlorinated (δ = 1.0-3.2 ppm) hydrocarbon moieties. The synthesized C-single-chain standard materials and respective spectroscopic data are useful to identify and quantify LCCPs in various materials and environmental samples. CP- and CO-distributions resemble the ones of existing SCCP and MCCP reference materials and technical mixtures. Furthermore, these materials now allow specific studies on the environmental fate and the transformation of long-chain chloroparaffins and chloroolefins.
技术氯化石蜡(CPs)是通过不同碳链长度(∼C-C)的正构烷烃原料的自由基氯化制备的。短链氯化石蜡(SCCPs,C-C)在《斯德哥尔摩公约》下被归类为持久性有机污染物(POPs)。该法规促使人们转而使用长链 CPs 作为替代品。因此,中链(MCCPs,C-C)和长链(LCCPs,C)CPs 已成为最近环境样品中的主要同系物。然而,目前尚无合适的长链 CPs 标准物质。在此,我们报告了一种从纯正构烷烃和氯化亚砜(SOCl)出发合成单链 C-CP 材料的化学合成方法。通过正相液相色谱对粗产物进行分级,并对合适的馏分进行合并,得到了四种不同氯化度(m=39-52%)的 C-CP 材料。此外,还从 CPs 中分离出了极性副产物,暂定鉴定为亚硫酸酯、硫酸盐和双硫酸盐二酯。新的单链材料通过 LC-MS、H-NMR 和 EA 进行了表征。LC-MS 为不同 C-CP 同系物和副产物提供了相对保留时间。全扫描质谱的数学解卷积揭示了四种单链 C-CP 材料中存在氯化石蜡(57-93%)和氯代烯烃(COs,7-26%)。CP 和 CO 的同系物分布和氯化度被推断出来。H-NMR 显示了单氯化(δ=3.2-5.3 ppm)和非氯化(δ=1.0-3.2 ppm)烃部分的化学位移范围。合成的 C-单链标准材料及其相应的光谱数据可用于识别和定量各种材料和环境样品中的 LCCPs。CP 和 CO 的分布与现有的 SCCP 和 MCCP 参考材料和技术混合物相似。此外,这些材料现在允许对长链氯化石蜡和氯代烯烃的环境归宿和转化进行专门研究。