A method for preparing triphenyl phosphate by extracting phenol from aryl phosphate production wastewater

Abstract

The invention discloses a method for preparing triphenyl phosphate through phenol extraction in aryl phosphoric ester production waste water. The method comprises the following steps of adding acid into the aryl phosphoric ester alkali washing waste water for regulating the pH value to 6 to 7; stirring and still standing layering to obtain an oil layer and waste water with the phenol content beinglower than 25000 ppm; adding triphenyl phosphate extraction agents into the waste water for stirring extraction; transferring an extraction phase into a distillation kettle for reduced pressure distillation dewatering; putting the dewatered extracts into an esterification kettle; next, adding phosphorus oxychloride and anhydrous magnesium chloride for esterification reaction to obtain triphenyl phosphate coarse products; sequentially performing acid washing, alkali washing, water washing and distillation treatment to finally obtain the qualified triphenyl phosphate finished product. Through the unified use of the triphenyl phosphate with the most simple phenol reuse process and least links as the extraction agents, one set of equipment can be used for solving the phenol recovery problem of various aryl phosphoric ester waste water in a concentrated way.

Description

technical field

[0001] The invention relates to a method for preparing triphenyl phosphate by extracting phenol from aryl phosphate production wastewater. Background technique

[0002] Aryl phosphate flame retardant is an important environmentally friendly halogen-free flame retardant, mainly used in engineering plastics flame retardant, common bisphenol A-bis (diphenyl phosphate), resorcinol-bis (diphenyl base phosphate), hydroquinone bis(diphenyl phosphate), tert-butylated aryl phosphate, etc. Due to the increasingly stringent restrictions on the use of halogen-containing flame retardants in European and American countries, the market demand for halogen-free aryl phosphate flame retardants is increasing year by year.

[0003] Since the production of aryl phosphate flame retardants mostly uses phenol as the final phosphorus oxychloride capping reagent, in order to ensure that the esterification reaction reaches the end and obtain a higher conversion rate, an excess of phen...

Examples

Embodiment 1

[0043] 1) Add 80.8kg of pickling wastewater to 300kg of alkali washing wastewater, stir at 40-60°C for 1 hour, adjust the pH value to 6-7, and then let it stand for 1 hour to separate 23.3kg of the lower oil layer and 355.46 kg of the upper layer of wastewater kg; Measure the phenol content of the upper layer wastewater to 22188ppm (phenol content detection: liquid chromatography external standard method);

[0044] 2) Add 29.62 kg of triphenyl phosphate extractant to the upper layer of wastewater obtained in step 1), the amount of the extractant added is 1 / 12 of the quality of the upper layer of wastewater, stirred for 1 hour at a temperature of 50-60 ° C, and then allowed to stand for 1 hour , separate 347.3kg water layer (the phenol content 887ppm of described water layer) and 37.42kg extraction layer, record the extraction layer phenol content 20152ppm;

[0045] 3) Transfer the extraction layer obtained in step 2) into a distillation kettle for dehydration by distillation u...

Embodiment 2

[0054] Other steps of embodiment 2 are identical with embodiment 1, and difference is that in step 1) after adding acid waste water, adjust pH value in waste water to be 2, measure step 1) the phenol content of upper layer waste water is 20158ppm.

Embodiment 3

[0055] The other steps of embodiment 3 are the same as in embodiment 1, except that in step 2), the extraction agent addition ratio is 1 / 10 of the water layer quality, and the final measurement step 2) the phenol content of the water layer is 573ppm.

technical field

[0001] The invention relates to a method for preparing triphenyl phosphate by extracting phenol from aryl phosphate production wastewater. Background technique

[0002] Aryl phosphate flame retardant is an important environmentally friendly halogen-free flame retardant, mainly used in engineering plastics flame retardant, common bisphenol A-bis (diphenyl phosphate), resorcinol-bis (diphenyl base phosphate), hydroquinone bis(diphenyl phosphate), tert-butylated aryl phosphate, etc. Due to the increasingly stringent restrictions on the use of halogen-containing flame retardants in European and American countries, the market demand for halogen-free aryl phosphate flame retardants is increasing year by year.

[0003] Since the production of aryl phosphate flame retardants mostly uses phenol as the final phosphorus oxychloride capping reagent, in order to ensure that the esterification reaction reaches the end and obtain a higher conversion rate, an excess of phen...

Examples

Embodiment 1

[0043] 1) Add 80.8kg of pickling wastewater to 300kg of alkali washing wastewater, stir at 40-60°C for 1 hour, adjust the pH value to 6-7, and then let it stand for 1 hour to separate 23.3kg of the lower oil layer and 355.46 kg of the upper layer of wastewater kg; Measure the phenol content of the upper layer wastewater to 22188ppm (phenol content detection: liquid chromatography external standard method);

[0044] 2) Add 29.62 kg of triphenyl phosphate extractant to the upper layer of wastewater obtained in step 1), the amount of the extractant added is 1 / 12 of the quality of the upper layer of wastewater, stirred for 1 hour at a temperature of 50-60 ° C, and then allowed to stand for 1 hour , separate 347.3kg water layer (the phenol content 887ppm of described water layer) and 37.42kg extraction layer, record the extraction layer phenol content 20152ppm;

[0045] 3) Transfer the extraction layer obtained in step 2) into a distillation kettle for dehydration by distillation u...

Embodiment 2

[0054] Other steps of embodiment 2 are identical with embodiment 1, and difference is that in step 1) after adding acid waste water, adjust pH value in waste water to be 2, measure step 1) the phenol content of upper layer waste water is 20158ppm.

Embodiment 3

[0055] The other steps of embodiment 3 are the same as in embodiment 1, except that in step 2), the extraction agent addition ratio is 1 / 10 of the water layer quality, and the final measurement step 2) the phenol content of the water layer is 573ppm.