Halogen-Mediated Conversion of Hydrocarbons to Commodities

Abstract

Halogen chemistry plays a central role in the industrial manufacture of various important chemicals, pharmaceuticals, and polymers. It involves the reaction of halogens or halides with hydrocarbons, leading to intermediate compounds which are readily converted to valuable commodities. These transformations, predominantly mediated by heterogeneous catalysts, have long been successfully applied in the production of polymers. Recent discoveries of abundant conventional and unconventional natural gas reserves have revitalized strong interest in these processes as the most cost-effective gas-to-liquid technologies. This review provides an in-depth analysis of the fundamental understanding and applied relevance of halogen chemistry in polymer industries (polyvinyl chloride, polyurethanes, and polycarbonates) and in the activation of light hydrocarbons. The reactions of particular interest include halogenation and oxyhalogenation of alkanes and alkenes, dehydrogenation of alkanes, conversion of alkyl halides, and oxidation of hydrogen halides, with emphasis on the catalyst, reactor, and process design. Perspectives on the challenges and directions for future development in this exciting field are provided.

Nitrogen‐Doped Carbons with Hierarchical Porosity via Chemical Blowing Towards Long‐Lived Metal‐Free Catalysts for Acetylene Hydrochlorination

“…In particular, nitrogen‐doped carbons (NCs), derived via carbonization of C/N‐precursors ( i. e ., polyaniline, polydopamine, ZIF‐8), stand out as the most promising candidates, rivaling the initial activity of their metal‐based analogues at elevated reaction temperatures . Despite these encouraging results, the applicability of NCs is hindered by their insufficient durability under relevant process conditions ( T =403‐453 K, P =1.5 bar, HCl : C 2 H 2 =1.1 : 1) . In particular, pore blockage through the formation of carbonaceous residues has been identified as the major reason for catalyst deactivation .…”

Polyhalogen and Polyinterhalogen Anions from Fluorine to Iodine

“…Yearly production and use of the halogens fluorine, chlorine, bromine, and iodine. [1] ogens and polyhalogens.N eutral interhalogen species (e.g., BrCl, BrF 3 ,C lF 5 ,I 2 Cl 6 ,I F 7 ), cationic (e.g., [I 3 ] + , [10] [Cl 3 ] + , [11] [Br 5 ] + , [12] [I 15 ] 3+ , [13] [Br 3 F 8 ] + [14] ), and anionic polyhalogen species are known. In contrast to the presently underexplored polyhalogen cations,o fw hich only af ew examples exist, the diversity of polyhalogen anions is significantly greater.…”

Kinetic and Deactivation Differences Among Methanol, Dimethyl Ether and Chloromethane as Stock for Hydrocarbons

“…In fact, this last step can be used to incorporate CO 2 into the cycle . On the other hand, the chloromethane can be obtained in one step from natural gas by oxychlorination . Among the three individual and final routes (on zeolite or zeotype catalyst), that of methanol to hydrocarbons (MTH) has attracted the greater interest and has been scale‐up in China, while the other two routes (DME and chloromethane to hydrocarbons, DTH and CTH respectively) are under study …”

“…[8,9] On the other hand, the chloromethane can be obtained in one step from natural gas by oxychlorination. [10] Among the three individual and final routes (on zeolite or zeotype catalyst), that of methanol to hydrocarbons (MTH) has attracted the greater interest and has been scale-up in China, [11] while the other two routes (DME and chloromethane to hydrocarbons, DTH and CTH respectively) are under study. [12][13][14][15][16] An overview of the extensive literature on MTH, DTH and CTH reactions indicate that (i) the most studied catalysts are H-ZSM-5 zeolite and SAPO-34 zeotype, whereas (ii) the mechanisms of reaction are essentially similar.…”