Diethyl Sulfate CAS 64-67-5

Introduction to Diethyl Sulfate

Diethyl Sulfate is an organosulfur compound consisting of two ethyl groups attached to a central sulfate moiety. Its molecular architecture features highly polarized sulfur-oxygen bonds, rendering the ethyl groups extremely susceptible to nucleophilic attack. At room temperature, the material appears as a colorless, transparent liquid with a faint characteristic peppermint-like odor. It remains practically insoluble in water but mixes completely with ethanol, diethyl ether and most polar organic solvents.

As a strong alkylating reagent, it readily transfers ethyl groups to a wide range of nucleophiles under mild reaction conditions. The ethyl sulfate anion serves as an excellent leaving group, driving alkylation reactions forward with minimal reversible side reactions. Its liquid state at ambient temperatures allows for precise metering and continuous dosing in automated chemical reactor systems.

Diethyl Sulfate Chemical & Physical Properties

Applications of Diethyl Sulfate

Pharmaceutical intermediate synthesis: Utilized extensively to ethylate active pharmaceutical ingredients and their precursors. The reagent selectively targets nitrogen, oxygen or sulfur atoms within complex heterocyclic scaffolds, enabling the construction of specialized drug molecules with precise structural modifications.

Agrochemical and dye manufacturing: Serves as a core building block for synthesizing crop protection agents and specialty dyes. The ethylation step significantly alters the lipophilicity and biological activity of target molecules, enhancing their efficacy and environmental fate profiles.

Quaternary ammonium salts: Reacts with tertiary amines to produce quaternary ammonium compounds. These resulting cationic surfactants are widely deployed in fabric softeners, biocides and phase-transfer catalysts due to their excellent surface-active properties.

Storage & Safety Precautions for Diethyl Sulfate

• Store in tightly sealed, moisture-proof HDPE or fluoropolymer-lined drums below 25 °C. The compound slowly hydrolyzes in the presence of water, generating corrosive sulfuric acid and ethanol, which degrades alkylating efficiency over time.
• The liquid is highly toxic, a known carcinogen and a severe alkylating agent that causes deep tissue burns and systemic poisoning upon skin contact. Wear a full-face supplied-air respirator, heavy-duty chemical suits and double-layered butyl rubber gloves during all transfer operations.
• Maintain strict temperature control using external cooling jackets during ethylation reactions. The alkylation process is highly exothermic; uncontrolled heat generation accelerates thermal decomposition and increases the risk of toxic vapor release.

Diethyl Sulfate FAQ

Q: How does Diethyl Sulfate function as an alkylating agent?

A: It acts as a powerful ethylating agent in organic synthesis, readily transferring ethyl groups to nucleophiles like amines, phenols and thiols. This high reactivity ensures excellent yields in manufacturing pharmaceutical intermediates and specialty dyes.

Q: Why is Diethyl Sulfate preferred over other ethylating agents?

A: It offers superior ethyl transfer efficiency and milder reaction conditions compared to harsher alkyl halides. It minimizes unwanted side reactions and provides high regioselectivity, making it an ideal reagent for synthesizing complex quaternary ammonium salts.

Q: What safety measures are required when handling Diethyl Sulfate?

A: It is highly toxic, carcinogenic and a severe alkylating hazard. Operators must handle it in closed, ventilated systems wearing full-face respirators and heavy-duty chemical suits. Immediate decontamination protocols are mandatory for any skin or eye contact.