Method for manufacturing nitrogen-containing compounds

• US 3,870,755 A
• Filed: 02/16/1972
• Issued: 03/11/1975
• Est. Priority Date: 05/27/1964
• Status: Expired due to Term

• Current Assignee: Mitsubishi Kasei Corp. (Mitsubishi Chemical Group Corp.)
• Original Assignee: Naoto Osako, Noriyoshi Yanai, Seiichi Kamo
• Inventors: Osako, Naoto, Kamo, Seiichi, Yanai, Noriyoshi
• Primary Examiner(s): Zitver, Leon
• Assistant Examiner(s): Glynn, Michael W.
• Application Number:
  US05/226,957
• Time in Patent Office: 1,119 Days
• Field of Search: 260/553R
• US Class Current: 564/59
• CPC Class Codes: B01J 19/18 Stationary reactors having moving elements inside B01J19/08, B01J19/26 take precedence
• CPC Class Codes: B01J 19/20 in the form of helices, e.g. screw reactors
• CPC Class Codes: B01J 2219/00128 by evaporation of reactants
• CPC Class Codes: B01J 2219/00177 controlling the pH
• CPC Class Codes: B01J 2219/182 horizontal
• CPC Class Codes: C05C 9/02 containing urea-formaldehyde condensates
• CPC Class Codes: C07C 273/1863 from urea
• CPC Class Codes: C07C 275/06 of an acyclic and saturated carbon skeleton

Abstract

The invention is directed to the making of solid alkylidene diurea and conducting the reaction between urea and an aldehyde by controlling the ratio of aldehyde to urea fed to a reactor so as to balance the heat evolved in the reaction between the aldehyde and urea with the latent heat of evaporation of excess of aldehyde, whereby the temperature of the reaction is maintained within predetermined limits. The product is of high purity and the yield is high.

Claims

1. In a method of manufacturing an alkylidene diurea product by the reaction of solid urea and an alkyl aldehyde having 3 to 4 carbon atoms in the substantial absence of a solvent for said urea in the presence of a aqueous acid catalyst selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, formic acid, monochloroacetic acid, oxalic acid, citric acid, tartaric acid, benzene sulfuric acid and toluene sulfonic acid, the improvement which comprises carrying out the reaction with stirring in a nongas-tight vessel;

continuously introducing solid urea into said reaction zone and continuously introducing said aldehyde in liquid form into said reaction zone by spraying in the ratio of 1 mole of urea to 0.6 to 1.1 moles of said aldehyde;

maintaining the temperature of the reaction mixture above the boiling temperature of said aldehyde in the reaction zone and up to 20*C higher than the said boiling temperature by an autogenous balance betWeen the heat of reaction and the latent heat of evaporation of by-product water and said aldehyde by permitting said water and unreacted aldehyde to evaporate;

maintaining the pH of reaction product less than 6 by addition of said catalyst to said reaction zone;

continuously discharging the evaporated aldehyde as vapor from said aldehyde vapor outlet; and

continuously removing the product from said zone.

2. A method according to claim 1 wherein said aldehyde is isobutyl aldehyde, said temperature is about 63* to 75*C and said urea is preheated to above 30*C.

3. A method according to claim 1 wherein the reactant mixture flows substantially horizontally, the urea is introduced at the entrance end of said zone, the product is removed from the opposite and discharge end of said zone, the aldehyde is introduced to said zone in a plurality of sprays.

4. A method according to claim 3 wherein said vessel has a product outlet and a urea inlet, said aldehyde is sprayed over an area adjacent to said urea inlet, and aldehyde vapor is removed from said zone at an area between said sprays and said outlet.

5. A method according to claim 3 wherein said vapor is freed from water, and the aldehyde is condensed and the condensate is returned to said sprays.

6. A method according to claim 3 wherein alkali is added to said product at said discharge end to neutralize the acidity thereof.

7. A method according to claim 1 wherein a part of said water is separated from said vapor.

8. A method according to claim 1 wherein said evaporated aldehyde is condensed and returned to said reaction vessel.

9. A method according to claim 1 wherein said acid catalyst is added in 30 to 50% aqueous solution.