Claims
- 1. A process for the preparation of a stable, aqueous suspension of methyl-N-(2-benzimidazolyl)-carbamate in the form of particles of a size less than 5 microns, which comprises the steps of:
- (a) treating an aqueous inorganic acid with carbendazime at a temperature of 100.degree. C. to 50.degree. C. to form an aqueous solution of an inorganic acid addition salt of methyl N-(2-benzimidazolyl)-carbamate and adding a wetting agent to said solution;
- (b) treating the solution at a temperature of 100.degree. C. to 50.degree. C. with an aqueous potassium, sodium or ammonium hydroxide solution or with ammonia gas in the presence of a dispersing agent with stirring to form methyl-N-(2-benzimidazolyl)-carbamate in suspension; and
- (c) thereafter maintaining the resulting suspension at a temperature of about 40.degree. to 60.degree. C. and adding an aqueous solution of an antideposit agent to said suspension.
- 2. The process defined in claim 1 wherein a protecting colloid is present during the reaction.
- 3. The process defined in claim 1 wherein the acid in step a is hydrochloric acid or phosphoric acid.
- 4. The process defined in claim 1 wherein the pH of the solution of the acid addition salt is adjusted to 4 to 9 and the methyl N-(2-benzimidazolyl)-carbamate concentration to 10 to 50% by proper selection of the concentration of the solution to be reacted relative to the methyl N-(2-benzimidazolyl)-carbamate or to hydrogen ion and of the mutual amounts of the solutions.
- 5. The process defined in claim 4 wherein the methyl N-(2-benzimidazolyl)-carbamate is present in an amount of 20 to 40% by weight.
- 6. The process defined in claim 1 which comprises reacting an aqueous solution of an acid addition salt of methyl N-(2-benzimidazolyl)-carbamate with an ammonium hydroxide solution or ammonia gas.
- 7. The process defined in claim 1 which comprises using lignin sulfonate or urea as a dispersing agent.
- 8. The process defined in claim 1 which comprises using alkylphenolpolyglycol ether or ethoxylated caster oil as a wetting agent.
- 9. The process defined in claim 2 which comprises using hydroxyethyl cellulose, polyvinylalcohol or polyvinylpyrrolidone as the protecting colloid.
- 10. The process defined in claim 1 which comprises using methyl silicate, a mineral oil, or a vegetable oil as an antifoaming agent.
Priority Claims (1)
Number |
Date |
Country |
Kind |
1142/80 |
May 1980 |
HUX |
|
Parent Case Info
This application is a continuation of application Ser. No. 260,161 filed May 4, 1981, now abandoned.
Foreign Referenced Citations (1)
Number |
Date |
Country |
1195180 |
Jun 1970 |
GBX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
260161 |
May 1981 |
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