| 摘要 |
Disclosed is a production method by the reaction of methanal (HCOH) with urea (CO(NH2)2) in two reaction steps. In the first step of the production the liquid intermediate is prepared in the way, that in reaction medium 2 to 6 wt. parts of urea per wt. part of methanal, whilst the reaction mixture contains also 16 to 44 parts of water. Before the reaction, during it or immediately past, pH of the reaction mixture is modified to the value 4 to 12.5, whilst for the acidity of the reaction mixture modification is advantageous to use a carbonate and/ or alkali metal hydroxide, or oxide and/ or calcium and/ or magnesium hydroxide. In the second step of methylene urea production by the said method produced liquid intermediate is mixed with aciditively reacting substance, in consequence to which the course of the condensation reactions is catalysed. By the effects of exothermic reaction the reaction mixture is warmed to the temperature higher than 40 C, also the sequential change of its reological characteristics occurs and subsequently to complete extinction of the liquid phase from the reaction mixture. The reaction product is isolated from reaction medium in solid or slightly plastic state. It is suitable, if to the reaction product after its isolation from the reaction medium suitable alkali added. Disclosed is also device for performing of this method.
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