Technical chlorinated paraffins (CPs) are produced via radical chlorination of n -alkane feedstocks with different carbon chain-lengths (∼C 10 –C 30). Short-chain CPs (SCCPs, C 10 –C 13) 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 14 –C 17) and long-chain (LCCPs, C > 17) 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 18 -CP-materials, starting with a pure n -alkane and sulfuryl chloride (SO 2 Cl 2). Fractionation of the crude product by normal-phase liquid-chromatography and pooling of suitable fractions yielded in four C 18 -CP-materials with different chlorination degrees (m Cl,EA = 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, 1H-NMR and EA. LC-MS provided Relative retention times for different C 18 -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 18 -CP-materials. Homologue distributions and chlorination degrees were deduced for CPs and COs. 1H-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 18 -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. [Display omitted] • Chlorination of n -alkanes with SO 2 Cl 2 is a versatile route to single-chain LCCPs. • Fractionation by LC resulted in CP materials with different chlorination degrees. • MS, NMR and elemental analysis were used to characterize synthetic C 18 -CP mixtures. • Proportions of olefinic and paraffinic material resemble those of SCCPs and MCCPs. • Sulfur- and oxygen-containing side-products were identified by LC-MS. [ABSTRACT FROM AUTHOR]