Sodium bisulfate, catalyst

Sangshetti et al. [18] synthesized a novel series of 1,3,4-oxadiazoles (vii) by a one pot reaction of hydrazide (vi), aromatic aldehyde in ethanol water using sodium bisulfate as the catalyst. All the compounds showed good antifungal activities. 

Diarock (Nitto Chemical Ind., Japan), marketed internationally for about a decade beginning in the mid-1960s, appears (from the manufacturer s literature) to be basic urea-formaldehyde resin (not a prepolymer). Cyanaloc 62 (American Cyanamid Company, Wayne, New Jersey) is a prepolymer marketed as a concentrated liquid which is diluted with water for field use. Sodium bisulfate is the catalyst normally used, and the relationship between catalyst concentration and setting time is shown in Fig. 

Fused sodium bisulfate is an effective catalyst for the dehydration of the aliphatic alcohols.88 Normal propyl alcohol is dehydrated at 125° to... 

Siddiqui and Farooq (2012) developed an improved methodology by using silica-supported sodium bisulfate (NaHS04-Si02) as a mild, highly efficient, and recyclable heterogeneous catalyst for the synthesis of pyranyl pyridine derivatives by the reaction of P-enaminone with active methylene compounds under thermal solvent-free conditions in excellent yields (Scheme 6.7). The present methodology offers very attractive features such as excellent yields of the product in a shorter reaction time, a simple workup procedure, economic viability, and reusability of the catalyst. 

The ACH process has been improved by Mitsubishi Gas [332]. Acetone cyanohydrin is first hydrolyzed to 2-hydroxyisobutylamide with a Mn02 catalyst the amide is then reacted with methyl formate to produce the methyl ester of 2-hydroxyisobutyric acid, with co-production of formamide (this reaction is catalyzed by sodium meth-oxide). The ester is finally dehydrated with an Na-Y zeolite to methyl methacrylate. Formamide is converted into cyanhydric acid, which is used to produce acetone cyanohydrin by reaction with acetone. The process is elegant, since it avoids the co-production of ammonium bisulfate, and no net income of HCN is present. However, there are many synthesis steps, and a high energy consumption. 

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