Lithium Hexamethyldisilazide (LHMDS), typ. 20 % solution in THF / Ethylbenzene (typ. 1.1 M)
LiN[Si(CH3)3]2
Lithium Hexamethyldisilazide (LHMDS; CAS 4039-32-1) is a lithium amide with molecular formula LiN[Si(CH3)3]2. It is supplied as a typical 20% solution in THF / Ethylbenzene.
LHMDS is commonly used as a strong non-nucleophilic base for selective deprotonation. Due to the low nucleophilicity it is often used in enolizations of ketones, aldehydes and esters.
LHMDS reacts readily with moisture and air and should be handled under dry, inert conditions. Consult the SDS and site-specific procedures for compatible materials, fire response, and storage.
Applications
Selective low nucleophilic base for e. g. enolisations.
Specifications
- LHMDS (active base) 19 - 21 %
Method of Analysis
Thermometric titration with 2-butanol for the determination of active base. Potentiometric titration of the methanolized product for the determination of total base. Detailed description available on request.Handling Instructions
LHMDS should be handled under inert gas atmosphere. Avoid contact with eyes, skin and clothes as well as inhalation. Vapors may form explosive mixtures with air. Vapors are heavier than air and may spread along floors. Flashback possible over considerable distance. Use only explosion-proof equipment. Take measures against electrostatic discharges. LHMDS decomposes in contact with humidity. In case of fire use dry extinguishers on basis of sodium chloride or limestone powder. Never use water or CO2-extinguishers. Pay also attention to the Safety Data Sheet.
Storage Instructions
LHMDS should be stored in tightly closed containers under exclusion of humidity at gentle temperatures. LHMDS starts to form crystalline precipitates on cooling below about -5 °C. Recommended storage temperature: min. 0 °C. When stored according to SDS the material is fairly stable. We still recommend to retest the material 12 months after date of analysis if included on CoA. If not included, use the date of manufacturing for the calculation. Keep away from heat, sparks and fire. Pay also attention to the Safety Data Sheet.
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The information presented herein is believed to be accurate and reliable but is presented without guarantee or responsibility on the part of Albemarle Corporation and its subsidiaries and affiliates. It is the responsibility of the user to comply with all applicable laws and regulations and to provide for a safe workplace. The user should consider any health or safety hazards or information contained herein only as a guide and should take those precautions which are necessary or prudent to instruct employees and to develop work practice procedures in order to promote a safe work environment. Further, nothing contained herein shall be taken as an inducement or recommendation to manufacture or use any of the herein materials or processes in violation of existing or future patent.
