Method for Photochemical Chlorination of Alkanes

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This patent describes a new method for the chlorination of alkanes (such as methane, ethane, propane, etc.) using photochemical or radical initiation. Instead of handling dangerous chlorine gas, the process uses stable polychloride ionic compounds that can release chlorine radicals when exposed to visible light (e.g., blue LED) or a radical starter. This enables controlled and efficient alkane chlorination under mild conditions without high temperatures or hazardous chlorine gas handling.

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• Manufacture of industrially important chlorinated alkanes (e.g., chloroform, carbon tetrachloride, chloromethane)
• Production of chemical intermediates for pharmaceuticals, agrochemicals, and polymers
• Replacement of traditional thermal or gas-based commercial chlorination plants with safer alternatives
• Laboratory-scale synthesis of chlorinated organic compounds
• Customized synthesis with selectivity control for R&D and specialty chemicals

BenefitsContent extracted from patent full text and abstract with AI.

• Significant safety improvements by avoiding direct use of toxic and corrosive chlorine gas
• Lower reaction temperatures compared to conventional thermal chlorination, reducing energy consumption
• Scalable process suitable for both laboratory and industrial applications
• Ability to control the extent of chlorination (mono-, di-, tri-, or tetra-chlorination) by adjusting reactant ratios
• Simpler and safer storage and transportation of the chlorine source as ionic liquids
• Potential use of visible light (including LEDs) means energy-efficient, accessible, and precise activation
• Versatile with a broad substrate scope, including various linear, branched, cyclic, and aromatic systems

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Inventors & Applicants

Patent Abstract

The present invention relates to a method for photochemical chlorination of alkanes comprising the steps of providing a mixture of at least one polychloride according to general formulae (I)        [N-R1aR2bR3cR4d][Cl-(Cl2)n]wherein the moities R1, R2, R3 and R4 are alkyl, preferably C1-C6 alkyl, or aryl, preferably C6-C10 aryl, wherein R1, R2, R3 and R4 can be the same or different from each other, wherein a, b, c, d are independently from each other 0, 1, 2 or 3, wherein the sum of a+b+c+d always has to be 4; wherein n> 0, preferably n >= 1, more preferably n = 1-6, even more preferably n = 1, 2, 3, 4, and at least one alkane according to general formulae (II)        CR5eR6fR7gR8hwherein the moities R5, R6, R7 and R8 are H, alkyl, aryl, halogen or two of R5, R6, R7 and R8 being part of a non-aromatic cyclic ring system, wherein R5, R6, R7 and R8 can be the same or different from each other, wherein at least one of the moities R5, R6, R7 and R8 is H, wherein e, f, g, h are independently from each other 0, 1, 2 or 3, wherein the sum of e+f+g+h always has to be 4; and irridiating the mixture at a wavelength in in the range between 350 nm and 1000 nm, preferably in the visable range between 400 nm and 800 nm, preferably between 420 nm and 780 nm, more preferably between 420 nm and 600 nm.