Chloromethyl Chlorosulfate CAS 49715-04-0

Additive for Lithium / Thionyl Chloride (Li/SOCl₂) Batteries

As a voltage delay inhibitor, chloromethyl chlorosulfate is widely applied in the electrolytes of primary lithium/thionyl chloride (Li/SOCl₂) and lithium/sulfuryl chloride (Li/SO₂Cl₂) batteries, solving the problems of voltage delay and low-voltage discharge of lithium batteries after long-term storage.

Li/SOCl₂ batteries feature high energy density, long shelf life and a wide operating temperature range, and are extensively used in military equipment, aerospace, medical devices and other fields.

However, the lithium anode tends to form a dense passivation film in the electrolyte, causing voltage delay and low discharge voltage during battery activation, which impairs service performance.

After adding 0.1%–1% CMCS to the electrolyte, CMCS preferentially adsorbs on the surface of the lithium anode, inhibits side reactions between the lithium anode and electrolyte, reduces the formation rate and thickness of the passivation film, lowers passivation film impedance, and significantly shortens the voltage delay time from several seconds to the millisecond level, improving discharge voltage stability.

Meanwhile, CMCS suppresses the corrosion of the lithium anode caused by impurities in the electrolyte and extends the battery shelf life from 10 years to more than 15 years. It is especially suitable for high-rate discharge scenarios such as pulse discharge, enhancing battery reliability and service life.

Novel Lithium Battery Electrolyte Solvent and Additive

As a new high-efficiency and safe lithium battery electrolyte solvent, CMCS can be compounded with traditional solvents such as dimethyl carbonate (DMC) and ethylene carbonate (EC) to improve the ionic conductivity, thermal stability and electrochemical stability of electrolytes.

CMCS possesses a high dielectric constant, which can effectively dissolve lithium salts such as LiPF₆ and LiBF₄ and enhance the ion conduction capacity of electrolytes. It exhibits excellent thermal stability and is not prone to decomposition at high temperature of 80 ℃, which can restrain thermal runaway of electrolytes and improve the safety of lithium batteries.

In addition, CMCS acts as an SEI film-forming additive. During the initial charge-discharge cycle of lithium batteries, it decomposes preferentially on the surface of the graphite anode to form a compact and stable SEI film. This inhibits electrolyte decomposition and graphite anode exfoliation, and improves the cycle stability and rate performance of lithium batteries.

Synthesis of Pesticide Intermediates

CMCS is used to synthesize pesticide intermediates including herbicides, insecticides and fungicides. It modifies the molecular structure of pesticides through chloromethylation reactions to enhance their biological activity, selectivity and environmental compatibility.

For instance, CMCS reacts with ethyl cyanoacetate to produce diethyl 2,4-dicyanoglutarate, which is further cyclized into 1,2-dicyanocyclopropane-1,2-dicarboxylate.

Such cyclopropane derivatives are core intermediates for synthesizing high-efficiency and low-toxicity herbicides, which can inhibit photosynthesis of weeds while maintaining high safety to crops.

Synthesis of Surfactants and Water Treatment Agents

CMCS can be used to synthesize chloromethyl-containing surfactants. Hydrophilic groups such as sulfonic acid groups and carboxyl groups are introduced via nucleophilic substitution reactions to prepare anionic surfactants with excellent emulsifying, dispersing and wetting properties, which are applied in detergents, cosmetics, textile printing and dyeing and other industries.

Furthermore, CMCS reacts with polyamines to generate chloromethyl-containing amine derivatives, which can be used as water treatment agents for flocculation, sterilization and corrosion inhibition in industrial wastewater. They effectively remove heavy metal ions, organic matter and microorganisms in water and improve water treatment efficiency.

Bioconjugate Chemistry and Chemical Biology

In bioconjugate chemistry, CMCS is applied to the labeling and modification of biomolecules including proteins, peptides and nucleic acids. Detectable groups such as fluorescent groups and biotin are introduced through chloromethylation reactions, enabling research on the localization, quantification and interaction of biomolecules.

For example, CMCS reacts with the carboxyl group of biotin to form biotin chloromethyl ester, which further reacts with amino groups of proteins to achieve biotin labeling of proteins. This is widely used in experiments such as Western blotting, immunofluorescence and affinity chromatography, providing strong support for research in chemical biology and molecular biology.

Synthesis of Amino Acid and Polypeptide Derivatives

In the synthesis of pharmaceutical intermediates, the core application of CMCS lies in the chloromethylation of Fmoc/Boc-protected amino acids, providing a crucial route for the preparation of polypeptide drugs and amino acid bioactive molecules. Traditional chloromethylation reagents, such as formaldehyde-hydrochloric acid system, tend to produce highly carcinogenic bis(chloromethyl) ether.

Under phase transfer catalysis conditions using a dichloromethane/water two-phase system with tetrabutylammonium bisulfate as the catalyst, CMCS can efficiently react with Fmoc or Boc-protected L-amino acids such as alanine and phenylalanine to form chloromethyl ester derivatives.The reaction yield exceeds 90% without generating carcinogenic by-products, showing remarkably better safety and selectivity than traditional processes.

Prodrug Synthesis

CMCS serves as a core reagent for the preparation of phosphonooxymethyl prodrugs and carboxylate ester prodrugs.

It solves the delivery challenges of clinical drugs by improving physicochemical properties including lipophilicity and water solubility, enhancing bioavailability and prolonging half-life. It reacts with dialkyl phosphates to form chloromethyl phosphates, which are further used to synthesize enzyme-sensitive phosphonooxymethyl prodrugs. Such prodrugs release the parent drug through esterase hydrolysis in vivo, target tumor tissues or inflammatory sites, and reduce systemic toxic and side effects.