Common solvent and solute catalysts in catalyst A33

Solutes and common diol solvents in catalyst A33

As we all know, A33 is a product commonly used in polyurethane catalytic reactions. According to the definition, it is a triethylenediamine solution with a mass fraction of 33%, and the solute is triethylenediamine. Because triethylenediamine is solid at room temperature, in order to facilitate For operational use, it is usually dissolved in diols, and the diols used as solvents generally include DPG, DEG, EG, PG, BDO, DMEA, etc.
Triethylenediamine, also known as 1,4-diazabicyclo[2.2.2]octane, triethylenediamine, triethylenediamine, has a slight ammonia smell and very little toxicity. The lethal poisoning dose for mice LD50 is 2g/kg. Its molecular structure has a unique cage structure, in which two nitrogen atoms are directly connected with three ethylene groups to form a bimolecular structure, which is very dense and symmetrical. Since the nitrogen atom not only has no other substituents to increase the steric hindrance, but also has a pair of very accessible empty electrons, in the catalytic foaming system, after the carbamate bond is formed, triethylenediamine will be freed and participate in The next catalytic reaction process. Therefore, although triethylenediamine is not a strong base, it shows extremely high catalytic activity for the reaction of isocyanate groups and active hydrogen compounds. According to estimates, in the water/polyol mixed system, the reaction to gelation accounts for 80%. , accounting for 20% of the foaming reaction.
 
Several Synthesis Methods of Triethylenediamine
1. The synthesis of triethylenediamine by high temperature deamination of polyamine compounds such as ethylenediamine under the action of catalyst-modified zeolite is a widely researched and applied process at present.
 
2. Piperazine and piperazine ethyl derivatives, such as N-hydroxyethylpiperazine, N-aminoethylpiperazine, etc. to synthesize triethylenediamine.
 
3. Dehydration of hydroxyethylamine compounds to synthesize triethylenediamine. This process uses ethanolamine or diethanolamine, triethanolamine, etc. as raw materials, reacts with ammonia water, etc. under the catalysis of a catalyst, and obtains the product through condensation and dehydration
 

Well, the above is a little knowledge about A33.