Methods of cleaning an N-methyl-2-pyrrolidone (NMP) purification and recovery system having an NMP-containing chemical waste stream, a separation tower fluidically coupled with the chemical waste stream, a reflux drum fluidically coupled with an upper section of the separation tower, a reboiler fluidically coupled with a lower section of the separation tower, and a purified NMP stream fluidically coupled with the reboiler. The methods include injecting a cleaning solution into the reflux drum and the reboiler with an amount of the cleaning solution sufficient to at least substantially fill the reflux drum and the reboiler, the cleaning solution comprising a solvent having a primary amine and a hydroxyl group, circulating the cleaning solution through at least the separation tower, the reflux drum, the reboiler for a period of time to solubilize foulants contained within the system, and draining the cleaning solution having foulants solubilized therein from the system.

Methods of cleaning an N-methyl-2-pyrrolidone (NMP) purification and recovery system having an NMP-containing chemical waste stream, a separation tower fluidically coupled with the chemical waste stream, a reflux drum fluidically coupled with an upper section of the separation tower, a reboiler fluidically coupled with a lower section of the separation tower, and a purified NMP stream fluidically coupled with the reboiler. The methods include injecting a cleaning solution into the reflux drum and the reboiler with an amount of the cleaning solution sufficient to at least substantially fill the reflux drum and the reboiler, the cleaning solution comprising a solvent having a primary amine and a hydroxyl group, circulating the cleaning solution through at least the separation tower, the reflux drum, the reboiler for a period of time to solubilize foulants contained within the system, and draining the cleaning solution having foulants solubilized therein from the system.

Disclosed herein is an efficient, economical, industrially advantageous, straight-through process for the preparation of cyclic amides, also referred as lactams, in substantially pure form and high yield, from the corresponding cyclic ketones and a hydroxylammonium salt, using a combination of amphoteric metal oxide or amphoteric masked metal oxide and a base.

Disclosed herein is an efficient, economical, industrially advantageous, straight-through process for the preparation of cyclic amides, also referred as lactams, in substantially pure form and high yield, from the corresponding cyclic ketones and a hydroxylammonium salt, using a combination of amphoteric metal oxide or amphoteric masked metal oxide and a base.

The present invention provides a method for producing an epoxy compound by a reaction of an olefin compound with hydrogen peroxide, wherein the epoxy compound is stably and safely produced using a hydrogen peroxide stabilizer for reducing an oxygen gas generated from hydrogen peroxide. A method for producing an epoxy compound by a reaction of an olefin compound with hydrogen peroxide, wherein the reaction is carried out in the presence of an organophosphorus compound in such a reaction medium that the pH is maintained within a range of more than 7.5 and less than 12.0. The olefin compound may be 1,3,5-tris-(alkenyl)-isocyanurate. The alkenyl group in the olefin compound may be 3-butenyl group, 4-pentenyl group, 5-hexenyl group, 6-heptenyl group, or 7-octenyl group. The epoxy compound may be 1,3,5-tris-(epoxyalkyl)-isocyanurate. The reaction medium may be such a reaction medium that the pH is maintained within a range of 8.0 to 10.5.

The present invention provides a method for producing an epoxy compound by a reaction of an olefin compound with hydrogen peroxide, wherein the epoxy compound is stably and safely produced using a hydrogen peroxide stabilizer for reducing an oxygen gas generated from hydrogen peroxide. A method for producing an epoxy compound by a reaction of an olefin compound with hydrogen peroxide, wherein the reaction is carried out in the presence of an organophosphorus compound in such a reaction medium that the pH is maintained within a range of more than 7.5 and less than 12.0. The olefin compound may be 1,3,5-tris-(alkenyl)-isocyanurate. The alkenyl group in the olefin compound may be 3-butenyl group, 4-pentenyl group, 5-hexenyl group, 6-heptenyl group, or 7-octenyl group. The epoxy compound may be 1,3,5-tris-(epoxyalkyl)-isocyanurate. The reaction medium may be such a reaction medium that the pH is maintained within a range of 8.0 to 10.5.

Disclosed herein is an efficient, economical, industrially advantageous, straight-through process for the preparation of cyclic amides, also referred as lactams, in substantially pure form and high yield, from the corresponding cyclic ketones and a hydroxylammonium salt, using a combination of amphoteric metal oxide or amphoteric masked metal oxide and a base.

Disclosed herein is an efficient, economical, industrially advantageous, straight-through process for the preparation of cyclic amides, also referred as lactams, in substantially pure form and high yield, from the corresponding cyclic ketones and a hydroxylammonium salt, using a combination of amphoteric metal oxide or amphoteric masked metal oxide and a base.

Process for purifying N-alkylpyrrolidones which due to a previous use comprise at least one of the impurities of the formula I or II ##STR00001##
where R is hydrogen or a C1-C20-alkyl group,
wherein a basic compound is added to the N-alkylpyrrolidone to be purified and the temperature of the mixture is at least 80 C. not more than 20 minutes after addition of the basic compound and N-alkylpyrrolidone is distilled off from the mixture obtained.

The present invention provides a continuous process for producing ammonium sulfate crystals, wherein said process comprises: (a) feeding to a first group of crystallization sections, which crystallization sections are heat integrated in series, a first aqueous ammonium sulfate solution that contains one or more impurities; (b) feeding to a second group of crystallization sections, which crystallization sections are heat integrated in series, a second aqueous ammonium sulfate solution that contains one or more impurities; (c) crystallizing ammonium sulfate crystals in each crystallization section respectively from each of said solutions of ammonium sulfate that contain one or more impurities; (d) purging a fraction of the ammonium sulfate solution that contains one or more impurities from each of said crystallization sections; and (e) discharging ammonium sulfate crystals from each crystallization section, characterized in that: (i) both the first group of crystallization sections and the second group of crystallization sections are together heat integrated in one series of crystallization sections; wherein the first group of crystallization sections operates at higher temperature than the second group of crystallization sections; and (ii) the composition of the first aqueous ammonium sulfate solution that contains one or more impurities is different to the composition of the second aqueous ammonium sulfate solution that contains one or more impurities. Further provided is apparatus suitable for producing ammonium sulfate crystals.