Dimethyl sulfate incident

A violent reaction occurred which shattered the flask when litre quantities of dimethyl sulfate and cone, aqueous ammonia were accidentally mixed. Use dilute ammonia in small quantities to destroy dimethyl sulfate [1], Similar incidents were noted previously with ammonia and other bases [2],... 

INCIDENT 3.2.2.1 DIMETHYL SULFATE AND SODIUM AZIDE EXPLOSION ... 

During the preparation of methyl azide from dimethyl sulfate and sodium azide, an explosion occurred. The same reaction had previously been carried out without incident. Upon investigation, the chemists found that Bretherick s Handbook of Reactive Chemical Hazards reported that this reaction can result in an explosion if the acidity of the solution drops to pH 5. It was surmised that sodium hydroxide, which was added to maintain the pH above 7, was not added at a sufficient rate to keep the solution at the required pH. Further steps (visible color indicator) were taken in subsequent preparations to ensure that the pH was maintained in the appropriate range. 

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