159474
This allows it to be used in the Knoevenagel condensation , for example in the preparation of CS gas : In related chemistry , malononitrile is a suitable starting material for the Gewald reaction , where the nitrile condenses with a ketone or aldehyde in the presence of elemental sulfur and a base to produce a 2-amino thiophene .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities:  
Answer:
 None