Analysis regeneration method of chlorinated phenol adsorption resin

Abstract

The invention discloses a desorption regeneration method of chlorinated phenol adsorption resin, which comprises the following steps: adsorbing 2, 4-dichlorophenol by using macroporous adsorption resin to obtain a byproduct 5-crude hydrochloric acid, then respectively carrying out desorption regeneration by using a first regenerant and a second regenerant, washing the obtained resin with water, and recycling to adsorb impurities in the crude hydrochloric acid. And the first regenerant and the second regenerant can be uniformly collected, separated and recycled. According to the method, methylbenzene and alcohol substances are respectively used as regenerant, efficient desorption and regeneration of the macroporous adsorption resin containing impurities such as chlorophenol are realized, and the method is simple, low in cost and capable of meeting environmental protection requirements.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of adsorption resins, and particularly relates to a desorption regeneration method of chlorophenol adsorption resin. BACKGROUND

[0002] In the field of organic chemical industry, 2,4-dichlorophenol is an important fine chemical product, which is mainly used for the production of pesticides, medicines and auxiliary products, such as herbicides, dyes, antitermites, preservatives, seed disinfectants, miticides, wood preservatives and the like in the agricultural field, and is used for the production of anthelmintic drug sulfobis dichlorophenol in the pharmaceutical industry; in addition, it can also be used as a solvent. The mainstream production process of 2,4-dichlorophenol is phenol direct chlorination method, that is, phenol is dissolved in a solvent, and then reacts with chlorine under the action of a catalyst to obtain "double-substituted" 2,4-dichlorophenol product. However, it is difficult to accurately control the ratio of single substitution and double substitution in the process of chlorination reaction, and the side reactions caused by "local reaction conditions are not uniform", so the by-product of 2,4-dichlorophenol, crude hydrochloric acid, generally contains single-chlorophenol, p-chlorophenol, 2,4,6-trichlorophenol and other polychlorinated phenol impurities, chlorinated benzoquinone and other organic impurities. At present, more resin adsorption operations are used to remove these impurities in industrial production to achieve the purpose of refining hydrochloric acid, but the resin adsorption will lose the refining capacity after reaching saturation, at which time the phenol-containing resin column needs to be desorbed and regenerated. The existing resin desorption method has the problems of low desorption regeneration efficiency, large desorption regeneration agent consumption and high difficulty in disposal of waste liquid, so it is urgent to develop a new desorption method for phenol-containing resin to improve the desorption regeneration efficiency, reduce the desorption regeneration agent consumption and reduce the disposal difficulty of desorption regeneration waste liquid.

[0003] Chinese patent CN101898937A discloses a method for regenerating polyamino macroporous resin adsorbed with phenol by using a mixture of water containing 0.2-2% sodium hydroxide (or potassium hydroxide) and methanol as eluent. The obtained phenol eluent is concentrated and then adjusted to a certain pH value by sodium hydroxide to recover by-product sodium phenolate. Chinese patent CN108097224A discloses a method for regenerating adsorbent and harmless treatment of phenolic substances by mixing water, adsorbent adsorbed with phenol, oxidizing agent and catalyst in a high-temperature and high-pressure reaction kettle to reach a supercritical state, and then completely or partially oxidizing the phenolic substances by oxidation reaction to generate harmless CO2 and H2O or resourceful H2 and CH4. Chinese patent CN108046454A discloses a method for disposing adsorbent resin of phenol-containing wastewater by using 5-8% sodium hydroxide solution for desorption and dilute sulfuric acid for activation. The method includes four steps of alkali desorption, blowing, acid activation and blowing. The solution generated by sodium hydroxide desorption is recovered by acidification. Chinese patent CN110252268A discloses a method for regenerating adsorbent resin of chlorobenzene production wastewater by using water vapor and benzene as desorption agents. The method uses water vapor for first desorption, benzene as second desorption agent, and steam for third desorption. Finally, the oil layers are combined and disposed uniformly. Chinese patent CN102949984A discloses a method for regenerating adsorbent resin of anthraquinone compounds in the process of producing H2O2 by using alcohol compounds. The waste liquid of alcohol compounds can be recycled by distillation tower. The method can effectively reduce the cost of resin regeneration, and the adsorption performance of the regenerated resin can be restored to more than 90%.

[0004] However, the current methods for desorption and regeneration of adsorbent resin still have problems such as large consumption of desorption solvent, complex operation process, high equipment requirement, etc. Most importantly, there is no good method for desorption and regeneration of chlorophenol adsorbent resin. The conventional dilute alkali desorption and regeneration method has low desorption efficiency and produces phenol-containing and salt-containing wastewater, which causes difficult wastewater disposal. SUMMARY

[0005] To solve the above technical problems, the present application provides a method for desorption and regeneration of chlorophenol adsorbent resin, which uses toluene and alcohol as regenerants to realize efficient desorption and regeneration of macroporous adsorbent resin containing chlorophenol and other impurities. The method is simple, low in cost and meets environmental protection requirements.

[0006] To achieve the above purpose, the present application provides a method for desorption and regeneration of chlorophenol adsorbent resin, which includes the following steps: (1) passing crude hydrochloric acid into macroporous adsorbent resin until saturation; (2) passing a first regenerant into the saturated macroporous adsorbent resin for desorption; (3) passing the second regenerant into the macroporous adsorption resin after step (2) is analyzed, and the analysis is completed for 0.5-5.0 h to complete the analysis regeneration; (4) collecting the first regenerant and the second regenerant after the analysis, and separating and recycling; the macroporous adsorption resin after the analysis regeneration is washed with water and recycled.

[0007] Preferably, the crude hydrochloric acid in step (1) is a by-product in the synthesis of 2,4-dichlorophenol by phenol catalytic chlorination, and the free phenol content is 0.05-0.15%.

[0008] Preferably, the pore size of the macroporous adsorption resin in step (1) is 10-15 nm, and the specific surface area is 500-650 m 2 / g.

[0009] Further preferably, the macroporous adsorption resin is seplite XDA series ultra-high crosslinking macroporous adsorption resin.

[0010] Preferably, the first regenerant in step (2) is toluene, and the amount is 0.5-3.0 BV.

[0011] Preferably, the analysis temperature in step (2) is 40-60℃, and the analysis time is 0.5-5.0 h.

[0012] Preferably, the second regenerant in step (3) is an alcohol substance, and the amount is 0.5-3.0 BV.

[0013] Further preferably, the alcohol substance is methanol and / or anhydrous ethanol.

[0014] More preferably, the second regenerant is methanol and anhydrous ethanol mixed in any volume ratio.

[0015] Preferably, the analysis temperature in step (3) is 40-60℃, and the analysis time is 0.5-5.0 h.

[0016] Preferably, the separation method in step (4) is any one or more of extraction, distillation and rectification.

[0017] Further preferably, after the first regenerant is obtained by using extraction for separation, further separation is needed by combining rectification or distillation to obtain the second regenerant.

[0018] More preferably, the extraction agent for the extraction is a NaOH solution with a mass percentage of 30-40% Further preferably, the distillation is atmospheric distillation or reduced pressure distillation; and the rectification is atmospheric rectification or reduced pressure rectification.

[0019] The beneficial effects of the present application are that: 1、The present application uses toluene and alcohol as regenerants to desorb and regenerate the adsorption resin saturated with chlorinated phenol and other impurities, can efficiently elute macroporous adsorption resin which specifically adsorbs chlorinated phenol and other phenolic impurities, and has high desorption and regeneration efficiency, improves work efficiency; toluene and alcohol can be recycled after desorption and regeneration, do not pollute the environment, meet environmental protection requirements; in addition, toluene and alcohol are bulk chemical raw materials which are easy to obtain, low in cost and widely available.

[0020] 2、The second regenerant is alcohol which is soluble in water, so that the regenerated resin can be recycled after water washing, the adsorption effect of macroporous adsorption resin can be ensured, and the product quality of hydrochloric acid can be further ensured.

[0021] 3、The desorption and regeneration method and the regenerant recovery method are simple, easy to implement, and simple to operate, dangerous and complex operation steps are avoided, the requirements for operators are reduced, the production cost is reduced, and large-scale industrial production is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure is a flowchart of the present application. DETAILED DESCRIPTION

[0023] The technical solutions of the present application will be further explained and described in combination with the drawings and specific embodiments. It should be noted that the following embodiments are preferred embodiments of the present application, and should not be understood as limiting the present application. The protection scope of the present application should be based on the content recorded in the claims. The modifications and replacements of the technical solutions of the present application made by those skilled in the art without creative labor fall within the protection scope of the present application.

[0024] In the following embodiments, the crude hydrochloric acid comes from a by-product of a domestic 2,4-dichlorophenol manufacturer, and is obtained by using water as an absorbent to absorb the hydrogen chloride generated by the side reaction during the synthesis of 2,4-dichlorophenol by phenol catalytic chlorination, and the free phenol content is 0.113303%; The macroporous adsorption resin is seplite® XDA resin, the average pore size is 15 nm, and the specific surface area is 650 m 2 / g.

[0025] Embodiment 1 (1) 2L of crude hydrochloric acid is taken and adsorbed through a resin column filled with 100mL of seplite® XDA resin, until adsorption is completed, to obtain saturated resin; (2) 50℃, 0.5BV (resin volume) of toluene is introduced into the saturated resin (the introduction speed is 0.5BV / h), to perform first desorption, to obtain first desorption liquid and crude resin; (3) the crude resin is introduced with 50°C, 0.5BV (resin volume) of methanol (mass percentage of 99%, the introduction speed is 0.5BV / h), the second resolution is carried out, the second resolution liquid and the regenerated resin are obtained; (4) the regenerated resin is introduced with 20°C, 1.0BV of ultrapure water for washing, the macroporous adsorption resin which can be recycled is obtained; (5) the first resolution liquid and the second resolution liquid are collected uniformly, then normal pressure rectification is carried out to obtain toluene and methanol respectively, the water content of the recovered methanol is 5.86%, the water content of the recovered toluene is 0.82%, then the recycling is carried out for the resolution and regeneration of the resin.

[0026] Example 2 (1) 2L of crude hydrochloric acid is taken and is adsorbed through a resin column filled with 100mL of seplite® XDA resin, until the adsorption is completed, the saturated resin is obtained; (2) the saturated resin is introduced with 40°C, 1.0BV (resin volume) of toluene (the introduction speed is 1.0BV / h), the first resolution is carried out, the first resolution liquid and the crude resin are obtained; (3) the crude resin is introduced with 40°C, 1.0BV (resin volume) of anhydrous ethanol (the introduction speed is 1.0BV / h), the second resolution is carried out, the second resolution liquid and the regenerated resin are obtained; (4) the regenerated resin is introduced with 20°C, 1.0BV of ultrapure water for washing, the macroporous adsorption resin which can be recycled is obtained; (5) the first resolution liquid and the second resolution liquid are collected uniformly, then normal pressure rectification is carried out to obtain toluene and anhydrous ethanol respectively, the water content of the recovered ethanol is 6.58%, the water content of the recovered toluene is 1.13%. Then the recycling is carried out for the resolution and regeneration of the resin.

[0027] Example 3 (1) 2L of crude hydrochloric acid is taken and is adsorbed through a resin column filled with 100mL of seplite® XDA resin, until the adsorption is completed, the saturated resin is obtained; (2) the saturated resin is introduced with 45°C, 2.0BV (resin volume) of toluene (the introduction speed is 1.0BV / h), the first resolution is carried out, the first resolution liquid and the crude resin are obtained; (3) the crude resin is introduced with 45°C, 2.0BV (resin volume) of the second regenerating agent (the introduction speed is 1.0BV / h), the second resolution is carried out, the second resolution liquid and the regenerated resin are obtained; the second regenerating agent is obtained by mixing methanol (mass percentage of 99%) and anhydrous ethanol according to the volume ratio of 1:9; (4) The regenerated resin is washed with 20°C, 1.0BV of ultrapure water to obtain macroporous adsorption resin that can be recycled; (5) The first eluent and the second eluent are collected together, and then subjected to vacuum rectification (pressure: -0.09MPa) to obtain toluene and the second regenerant, respectively, wherein the water content of the second regenerant is 6.82%, and the water content of the recovered toluene is 1.64%. Then the resin is subjected to elution and regeneration in a recycling manner.

[0028] Example 4 (1) 2L of crude hydrochloric acid is subjected to adsorption through a resin column filled with 100mL of seplite® XDA resin, until adsorption is completed, to obtain saturated resin; (2) The saturated resin is subjected to first elution by passing 55°C, 2.5BV (resin volume) of toluene (passing speed: 2.0BV / h) therethrough to obtain first eluent and crude resin; (3) The crude resin is subjected to second elution by passing 45°C, 2.0BV (resin volume) of second regenerant (passing speed: 2.0BV / h) therethrough to obtain second eluent and regenerated resin; the second regenerant is obtained by mixing methanol (mass percentage: 99%) and anhydrous ethanol in a volume ratio of 1:1; (4) The regenerated resin is washed with 20°C, 1.0BV of ultrapure water to obtain macroporous adsorption resin that can be recycled; (5) The first eluent and the second eluent are collected together, and then subjected to vacuum rectification (pressure: -0.09MPa) to obtain toluene and the second regenerant, respectively, wherein the water content of the second regenerant is 6.82%, and the water content of the recovered toluene is 1.64%. Then the resin is subjected to elution and regeneration in a recycling manner.

[0029] Example 5 (1) 2L of crude hydrochloric acid is subjected to adsorption through a resin column filled with 100mL of seplite® XDA resin, until adsorption is completed, to obtain saturated resin; (2) The saturated resin is subjected to first elution by passing 60°C, 3.0BV (resin volume) of toluene (passing speed: 2.0BV / h) therethrough to obtain first eluent and crude resin; (3) The crude resin is subjected to second elution by passing 60°C, 3.0BV (resin volume) of second regenerant (passing speed: 2.0BV / h) therethrough to obtain second eluent and regenerated resin; the second regenerant is obtained by mixing methanol (mass percentage: 99%) and anhydrous ethanol in a volume ratio of 9:1; (4) the regenerated resin is washed with 20°C, 1.0BV of ultrapure water to obtain macroporous adsorption resin that can be recycled; (5) the first elution liquid and the second elution liquid are collected together, and then atmospheric distillation is performed to obtain toluene and methanol, respectively, wherein the water content of the recovered methanol is 8.74%, and the water content of the recovered toluene is 1.23%; then the resin is regenerated by recycling.

[0030] Example 6 (1) 2L of crude hydrochloric acid is adsorbed by a resin column filled with 100mL of seplite® XDA resin, until adsorption is completed, to obtain saturated resin; (2) the saturated resin is eluted with 40°C, 0.5BV (resin volume) of toluene (the elution speed is 1.0BV / h) to perform first elution, to obtain a first elution liquid and crude resin; (3) the crude resin is eluted with 60°C, 3.0BV (resin volume) of a second regenerating agent (the elution speed is 2.0BV / h) to perform second elution, to obtain a second elution liquid and regenerated resin; the second regenerating agent is obtained by mixing methanol (mass percentage is 99%) and anhydrous ethanol according to a volume ratio of 9:1; (4) the regenerated resin is washed with 20°C, 1.0BV of ultrapure water to obtain macroporous adsorption resin that can be recycled; (5) the first elution liquid and the second elution liquid are collected together, and then reduced pressure distillation (the pressure is-0.09MPa) is performed to obtain toluene and methanol, respectively, wherein the water content of the second regenerating agent is 10.84%, and the water content of the recovered toluene is 1.32%; then the resin is regenerated by recycling.

[0031] Example 7 (1) 2L of crude hydrochloric acid is adsorbed by a resin column filled with 100mL of seplite® XDA resin, until adsorption is completed, to obtain saturated resin; (2) the saturated resin is eluted with 60°C, 3.0BV (resin volume) of toluene (the elution speed is 2.0BV / h) to perform first elution, to obtain a first elution liquid and crude resin; (3) the crude resin is eluted with 40°C, 0.5BV (resin volume) of methanol (the water content is 10%, the elution speed is 1.0BV / h) to perform second elution, to obtain a second elution liquid and regenerated resin; (4) the regenerated resin is washed with 20°C, 1.0BV of ultrapure water to obtain macroporous adsorption resin that can be recycled; (5) Collecting the first elution liquid and the second elution liquid together, and then performing vacuum distillation (pressure: -0.09 MPa) to obtain toluene and the second regenerant, wherein the water content of the second regenerant is 11.50%, and the water content of the recovered toluene is 1.44%. Then, the resin is regenerated by recycling.

[0032] Example 8 (1) 2 L of crude hydrochloric acid was taken and adsorbed by a resin column filled with 100 mL of XDA resin, until adsorption was completed, to obtain saturated resin; (2) 50℃, 0.5 BV (resin volume) of toluene was introduced into the saturated resin (the introduction speed was 1.0 BV / h), to perform the first elution, to obtain the first elution liquid and crude resin; (3) 50℃, 0.5 BV (resin volume) of methanol (content: 99%) was introduced into the crude resin (the introduction speed was 1.0 BV / h), to perform the second elution, to obtain the second elution liquid and regenerated resin; (4) 20℃, 1.0 BV of ultrapure water was introduced into the regenerated resin, to obtain macroporous adsorption resin which could be recycled; (5) Collecting the first elution liquid and the second elution liquid together, and then performing vacuum distillation (pressure: -0.09 MPa) to obtain toluene and the second regenerant, wherein the water content of the second regenerant is 11.50%, and the water content of the recovered toluene is 1.44%. Then, the resin is regenerated by recycling.

[0033] Comparative Example 1 The method and steps were the same as those in Example 1, except that step (3) was omitted, and only toluene was used for one elution, and then the crude resin was directly washed.

[0034] Comparative Example 2 The method and steps were the same as those in Example 1, except that step (2) was omitted, and only methanol (mass percentage: 99%) was used for one elution, and then the eluted resin was directly washed.

[0035] Comparative Example 3 The method and steps were the same as those in Example 1, except that the temperature of the regenerant in step (2) and step (3) was changed to 30℃, and the first elution and the second elution were performed, respectively.

[0036] Comparative Example 4 The method and steps were the same as those in Example 1, except that the temperature of the regenerant in step (2) and step (3) was changed to 70℃, and the first elution and the second elution were performed, respectively.

[0037] Comparative Example 5 The method and steps were the same as those in Example 1, except that the regeneration time in step (2) and step (3) was changed to 0.5 h, and the first elution and the second elution were performed, respectively.

[0038] Comparative Example 6 The method and steps are the same as in Example 1, except that 99% methanol in step (3) is replaced by methanol with a water content of 20%, and the second elution is completed.

[0039] Comparative Example 7 (1) Take 2 L of crude hydrochloric acid and pass it through a resin column filled with 100 mL of XDA resin until adsorption is complete, to obtain saturated resin; (2) Pass 50°C, 1.0 BV (resin volume) of NaOH solution (5% by mass) into the saturated resin at a speed of 1.0 BV / h, to perform elution, to obtain eluate and regenerated resin; (3) Pass 20°C, 2.0 BV of ultrapure water into the regenerated resin, to obtain macroporous adsorption resin that can be recycled; (4) Use reduced pressure distillation to treat the eluate.

[0040] Example 9 Take the ultrapure water washing liquid, eluate, and toluene, methanol, etc. obtained after treatment of the eluate in the elution process of the above examples and comparative examples, and use 4-aminoantipyrine spectrophotometry (referring to “HJ 503-2009 Water Quality-Determination of Phenol”) to detect the free phenol content, and the results are shown in Table 1: Table 1 Free phenol content in various solutions

[0041] As shown in Table 1, toluene as the first eluant and methanol (content 99%) or anhydrous ethanol or a mixed solution of methanol and anhydrous ethanol as the second eluant in Examples 1, 2, 3, 4, 5, and 6 can all play a good elution effect on the saturated resin column, and the elution efficiency is about 95% according to the adsorption amount and elution amount. As shown in Example 7, methanol with a water content of 10% as the second eluant still has a good regeneration effect. As shown in Example 8, toluene and methanol recovered by atmospheric distillation still have a good regeneration effect when they are used for 5 times in the “adsorption-elution” cycle.

[0042] As shown in Examples 1-3 and 5-8, the methods of reduced pressure distillation, atmospheric distillation, reduced pressure distillation, and atmospheric distillation can all be used to recover toluene, methanol, ethanol, and a solution of methanol and ethanol in any proportion. In particular, as shown in Example 4, the toluene eluate can also be recovered by extraction, and the free phenol content in the recovered toluene is 315.63 ppm.

[0043] From the comparative examples 1 and 2, it can be seen that the first regenerant or the second regenerant alone cannot achieve a better resolution effect. From the comparative examples 3 and 4, it can be seen that when the resolution temperature is too low, the resolution effect will decrease obviously; when the resolution temperature is too high, the volatilization loss of the regenerant is large, resulting in that the free phenol content in the second regenerant resolution liquid obtained increases obviously, but the converted resolution efficiency is low. From the comparative example 5, it can be seen that when the resolution time is too short, the resolution effect will decrease obviously. From the comparative example 6, it can be seen that when the water content in the recovered methanol is 20%, the resolution effect will decrease. From the comparative example 7, it can be seen that when the original process uses 5% NaOH for resolution, the free phenol content in the resolution liquid is only 0.74%, and the converted resolution efficiency is only 25.60%.

Claims

1. A method for the desorption and regeneration of a chlorophenol adsorption resin, characterized in that: Includes the following steps: (1) Pass crude hydrochloric acid into a macroporous adsorption resin until saturation; (2) The first regenerant is introduced into the saturated macroporous adsorption resin for desorption; (3) Pass the second regenerator into the macroporous adsorption resin after the analysis in step (2) and analyze for 0.5-5.0 h to complete the analysis and regeneration; (4) Collect the first and second regenerators after analysis and separate and recycle them; the macroporous adsorption resin after analysis and regeneration is washed with water and then recycled.

2. The method for desorption and regeneration of a chlorophenol adsorption resin according to claim 1, characterized in that: The crude hydrochloric acid mentioned in step (1) is a byproduct of the synthesis of 2,4-dichlorophenol by phenol catalytic chlorination, and the free phenol content is 0.05-0.15%.

3. The desorption and regeneration method for a chlorophenol adsorption resin according to claim 1, characterized in that: The macroporous adsorption resin described in step (1) has a pore size of 10-15 nm and a specific surface area of ​​500-650 m². 2 / g.

4. The method for desorption and regeneration of a chlorophenol adsorption resin according to claim 1, characterized in that: The first regenerant mentioned in step (2) is toluene, and the dosage is 0.5-3.0 BV.

5. The method for desorption and regeneration of a chlorophenol adsorption resin according to claim 1, characterized in that: The analysis temperature in step (2) is 40-60℃ and the analysis time is 0.5-5.0h.

6. The desorption and regeneration method for a chlorophenol adsorption resin according to claim 1, characterized in that: The second regenerator mentioned in step (3) is an alcoholic substance, and the dosage is 0.5-3.0 BV.

7. The method for desorption and regeneration of a chlorophenol adsorption resin according to claim 6, characterized in that: The alcohols are methanol and / or anhydrous ethanol.

8. The desorption and regeneration method for a chlorophenol adsorption resin according to claim 7, characterized in that: The second regenerant is a mixture of methanol and anhydrous ethanol in any volume ratio.

9. The method for desorption and regeneration of a chlorophenol adsorption resin according to claim 1, characterized in that: The analysis temperature in step (3) is 40-60℃ and the analysis time is 0.5-5.0h.

10. The method for desorption and regeneration of a chlorophenol adsorption resin according to claim 1, characterized in that: The separation method described in step (4) is one or more of extraction, distillation and rectification.

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