(Хлорметил) тииран

Description

(Chloromethyl)thiirane, also known as epithiochlorohydrin or thioepichlorohydrin, is a sulfur analogue of epichlorohydrin in which the oxygen atom of the epoxide ring is replaced by a sulfur atom. The three-membered thiyrane (episulfide) ring, combined with a chloromethyl group, makes the compound a bifunctional alkylating reagent: chlorine can be replaced by nucleophiles, and the strained sulfur-containing ring opens under the influence of the same nucleophiles, which opens the way to the production of mercaptoalcohols, thioglycidyl ethers and organosulfur polymers.

Basic Attributes

• CAS No.: 3221-15-6
• Chemical formula: C3H5ClS
• English name: (Chloromethyl)thiirane
• Molecular weight: 108.59
• Exact weight: 108.59
• NSC Number: 36644
• HS code: 2903199000
• PSA specifications: 25.3
• XLogP3: 0.57

Physico-chemical characteristics

Appearance: transparent liquid from colorless to light yellow. The polar surface area of ​​the molecule, 25.3 Ų, is higher than that of most simple organochlorine compounds of comparable mass, which is due to the presence of a sulfur atom in the three-membered ring. The XLogP3 partition coefficient of 0.57 indicates moderate solubility in water and good miscibility with organic solvents.

Scope of application

• comonomer and cross-linking agent in the production of polysulfide rubbers and sealants of organosulfur chemistry
• starting reagent for the synthesis of thioglycidyl ethers and other sulfur-containing epoxy derivatives
• alkylating reagent in fine organic synthesis for the introduction of thiirane and chloromethyl fragments
• intermediate in the preparation of mercaptoalcohols by opening of the thiirane ring with nucleophiles

Reactivity

The chloromethyl group reacts with nucleophiles (amines, thiols, alkoxides) according to the classical mechanism of nucleophilic substitution, and the three-membered thiirane ring, strained and electrophilic like an epoxide, is opened by the same nucleophilic agents to form sulfur-containing addition products. This combination of two reaction centers in one molecule makes the compound a convenient building block for the preparation of bifunctional sulfur monomers.

Storage and transportation

The substance is stored in a sealed container, in a cool, ventilated room, away from heat sources, open flames and strong nucleophilic reagents (amines, thiols), which can cause undesirable ring opening during storage. Work with liquid is carried out in a fume hood using respiratory and skin protection, since organosulfur chlorine derivatives have a pronounced pungent odor and irritating effect.

Practical features of work

When the thiirane ring is opened by nucleophiles, the reaction usually proceeds regioselectively at the less substituted carbon atom of the ring, which makes it possible to predictably construct the target mercaptoalcohol or thioether structure. The chloromethyl group remains intact and can be used in the next synthetic step, or, conversely, is the first to undergo a substitution reaction if the target molecule requires preservation of the thiirane ring. This sequence of transformations—ring opening, then substitution of chlorine, or vice versa—is determined by the choice of conditions and the nature of the nucleophile.

Related compounds

(Chloromethyl)thiirane is compared with epichlorohydrin, its oxygen analogue, widely used in the production of epoxy resins. Replacing oxygen with sulfur changes the electronic properties of the cycle and makes the compound more prone to reactions with soft sulfur- and nitrogen-containing nucleophiles, which determines its niche use in the synthesis of organosulfur polymers and monomers, where the oxygen analogue does not provide the desired properties of the material.