CS239397B1 - Process for producing potassium phthalimide - Google Patents

Abstract

The present invention provides a process for producing potassium phthalimide by reacting suspended phthalimide in a hot polar solvent at 60 ° C and potassium hydroxide dissolved in a polar solvent at 50 to 60 ° C and refluxing, cooling and isolating potassium phthalimide from the solvent.

Description

The present invention provides a process for producing potassium phthalimide by reacting suspended phthalimide in a hot polar solvent at 60 ° C and potassium hydroxide dissolved in a polar solvent at 50 to 60 ° C and refluxing, cooling and isolating potassium phthalimide from the solvent. 239397 239397

One of the basic raw materials in various organic syntheses is potassium phthalimide. For example, it is used as an intermediate in the manufacture of N-substituted thiophthalimides which are used as vulcanization retarders.

Potassium phthalimide is prepared by the action of potassium hydroxide on phthalimide or the Gabriel reaction. The Gabriel reaction can also be used to prepare 1,4-diaminobutane where potassium phthalimide is obtained as an intermediate.

Potassium phthalimide can also be obtained as an intermediate in the preparation of procainamide hydrochloride, or as a condensation product of primary amine with violet anhydride.

In addition to the above-mentioned methods of preparation, Landsberg discloses the preparation of the sodium and potassium salts of phthalimide by the action of sodium or potassium ethanolate on phthalimide. According to Hammick, good yields of sodium and potassium phthalimide were achieved using sodium or potassium amyloxide in the amyl alcohol.

Said preparation methods do not give satisfactory extracts. The use of ethanolic solutions of the hydroxides of the metals in each case leads to the use of large volumes of solvents, which is considerable in energy recovery when regenerated.

It has now been found that the abovementioned drawbacks can be avoided according to the present invention by adding to the phthalimide suspension in a polar solvent at 60 ° C an equivalent amount of potassium hydroxide solution in a polar solvent at 50 ° -60 ° C and with stirring, the mixture is refluxed for 5 to 120 minutes and, after cooling, potassium phthalimide is isolated by filtration.

The solvent used is recovered by distillation.

The subject matter of the invention is documented! the following examples. Example 1

To 100 ml of isobutanol was added 8 g of phthalimide, which was partially dissolved under stirring at 60 DEG C. and partly formed in a solvent. 100 ml of isobutanol containing 8.94 wt. KOH at 60 ° C and refluxed for 30 minutes. After cooling, 8.8 g of potassium phthalimide was obtained, representing a yield of 87.5%. Analysis of potassium phthalimide revealed a potassium content of 20.1 and a nitrogen content of 7.18%. Example 2 An 8.95% suspension of lithium in isobutanol at 60 ° C was mixed with an alcoholic solution of KOH in isobutanol containing 9% KOH at 55 ° C. After refluxing for 10 minutes, the mixture was cooled, potassium phthalimide was isolated, yielding 90.2%. Example 3

To dissolve phthalimide and KOH, the filtrate from experiments 1 and 2 obtained after isolating potassium phthalimide was used. Moreover, the experimental conditions were the same as in Example 1. After filtering off the potassium phthalimide, the precipitate was washed with pure alcohol and dried. The experiment yield was 97%. The filtrate was repeated 4 times, with potassium phthalimide extracts as follows: 97.0%, 100%, 98.5%, 97%.

Claims (1)

SUBJECT A method of producing potassium phthalimide by reacting phthalimide and potassium hydroxide, adding to the suspension of phthalimide in a polar solvent at 60 degrees Celsius an equivalent amount of potassium hydroxide in a hot solution in a polar solvent at 50-60 ° C, mixture it is refluxed for 5 to 120 minutes and after cooling, potassium phthalimide is isolated from the solvent which is recycled to sleep in the production of potassium phthalimide.