DETDA Structure

Diethyltoluenediamine(DETDA) Production Process

A1C13 with Zn and not as a co-catalyst products. Because the poor thermal stability of AlCl3, easy to coke at high temperatures, and decomposition release HCl, severe corrosion of the equipment. The choice is more appropriate aluminum alkyl catalyst, which use TEA, the conversion rate and reactivity are high. In this study, TEA as a synthetic catalyst.


The alkylation reaction is a multi-step reaction, accompanied by N- alkylation side reaction. Reaction temperature, reaction pressure, reaction time and amount of catalyst, the ratio of ingredients is a major factor affecting the reaction. Our crude DETDA content as the evaluation index. Comprehensive selected by orthogonal preferred process conditions: temperature 300 ;, reaction pressure 10.0 MPa, reaction time 7 H, catalyst 18.6%, (weight fraction), Et (molar ratio) of 1: 2.1.


Under these conditions, changes in the amount of catalyst, examine its impact on the synthesis, to reduce the amount of catalyst and reduce costs. When the catalyst amount is less than 15%, the product TDA content increases, the conversion rate, the yield dropped significantly and the material purified difficulties; increase the dosage, synthesis conditions improve small, Huai dosage increased by 1, DETDA improve only 5%, and the viscous material, post-processing difficulties.


We selected according to the following methods and product properties were studied.
 
A direct distillation method is simple, but at a high temperature, catalyst damage products, low yields, more residue.
 
B. adding excess alkali catalyst for the partial conversion of soluble aluminate

In water, it becomes clear two phases facilitate separation, aluminum is easily removed. But the consumption of base volume.
   
C. water or adding an appropriate amount of lye catalyst is converted to Al (OH) 3 floc, is difficult and the organic phase separated. Al (OH) 3 in entrainment large amounts of organic phase, suffered serious losses.
   
D. brine large particles Al (OH) 3 precipitates, clear two-phase separation. Add salt, increasing the density of the aqueous phase, the organic phase was reduced
Solubility in water and sediment and content of, the separation quickly. High yield, simple operation and low cost.
   
Selection Method D as a way to remove the catalyst, the experiment proved to be feasible.

Refined

After removal of the catalyst, in addition to crude DETDA, but also contains a variety of aromatic amine derivatives. These substances similar to density, solubility similar, the same chemical properties, separation difficult extraction, crystallization and other physical and chemical methods. DETDA boiling point 308 ℃, boiling point similar to other derivatives, we use vacuum distillation method, lower boiling point, increasing the boiling point difference. Calculated and measured equilibrium equation and calculate the equilibrium curve Mixture, we obtained a better distillation process conditions, so that the average purity of over 98%.


Performance Testing

Products cured in an oven at 120 ℃ in 12h, at room temperature for 7 days, according to the West German standard DNI53504 test product performance and imports considerably:

Project production DETDA import DETDA,
Tensile strength (MPa) 18.52 16.9
Elongation at break (%) 300 280
Flexural modulus (MPa) 208,5 210.8
Flexural strength (MPa) 10.63 10.98

Diethyltoluenediamine packing： net weight 200KG/ galvanized iron drum (a small cabinet pallet loaded 16 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons or 23 tons of ISOTANK).

                                 DIETHYL TOLUENE DIAMINE (DETDA) TDS