Background
Hydrogen peroxide is a green oxidant, and as disclosed in USP4833260, epichlorohydrin can be synthesized efficiently and cleanly by the epoxidation reaction of 3-chloropropene with hydrogen peroxide in the presence of a titanium silicalite catalyst and methanol as a solvent. Epichlorohydrin is an important basic organic chemical raw material and intermediate, and is widely applied to synthesis of epoxy resin, chlorohydrin rubber, medicines, pesticides, surfactants, plasticizers and other industrial products.
CN101747296A and CN101747297A disclose methods for producing epichlorohydrin by epoxidation reaction of 3-chloropropene and hydrogen peroxide, which realizes continuous and stable synthesis of epichlorohydrin for a long time under the condition that the conversion rate of hydrogen peroxide is higher than 97% and the selectivity of epichlorohydrin is higher than 95%. CN101293882A further discloses a method for economically and efficiently separating epichlorohydrin from the epoxidation reaction product of 3-chloropropene and hydrogen peroxide, which can produce a certain amount of epoxidation wastewater while obtaining epichlorohydrin product and recovering 3-chloropropene and methanol.
The epoxidation wastewater contains 0.1 to 1 mass% of 3-chloro-1, 2-propanediol and 0.2 to 2 mass% of chlorinated organic compounds such as chloropropanediol monomethyl ether. It is known that chlorinated organic compounds are a class of surface water and soil pollutants (baulun, zhang jun, wuhong, lao warrior, rejuvenation, research progress on biodegradation of halogenated organic substances, journal of chinese health examination, 2002, 12 (3): 376 to 380), especially 3-chloro-1, 2-propanediol, as reported by kunshun et al (cynhun, sunset, galloanser, sun juniper, berubine. food pollutants 3-chloro-1, 2-propanediol toxicology progress, food industry science and technology, 2013-chloro-1, 2-propanediol is a chlorinated organic compound with obvious toxicity and carcinogenicity to rodents. Therefore, the toxic and harmful epoxidation wastewater needs to be subjected to harmless treatment to remove the 3-chloro-1, 2-propanediol and chloropropanediol monomethyl ether.
For the epoxidation wastewater of epoxy chloropropane synthesized by epoxidizing 3-chloropropene containing 3-chloro-1, 2-propanediol and chloropropanediol monomethyl ether with hydrogen peroxide, no published report for directly decomposing the 3-chloro-1, 2-propanediol and chloropropanediol monomethyl ether exists.
Detailed Description
The harmless treatment method of the epoxidation wastewater provided by the invention is implemented as follows:
a harmless treatment method of epoxidized wastewater comprises the following steps: a) contacting and mixing epoxidation wastewater generated in the process of synthesizing epichlorohydrin by epoxidizing 3-chloropropene and hydrogen peroxide with an alkaline aqueous solution in a wastewater treatment reactor to convert 3-chloro-1, 2-propanediol in the wastewater into glycerol; b) optionally, neutralizing the reaction mixture obtained in step a); the alkaline aqueous solution is an aqueous solution of alkali metal hydroxide, alkaline earth metal hydroxide and alkali metal salt.
In the method for the harmless treatment of the epoxidized wastewater, the content of 3-chloro-1, 2-propanediol in the epoxidized wastewater is 0.1-1 mass%. Preferably, the harmless treatment method of the epoxidation wastewater provided by the invention is used for preferably treating wastewater containing 3-chloro-1, 2-propanediol and chloropropanediol monomethyl ether, wherein the content of the chloropropanediol monomethyl ether is 0.2-2 mass%.
In the method for treating epoxidation wastewater provided by the invention, the alkali metal hydroxide is lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide and cesium hydroxide, and preferably lithium hydroxide, sodium hydroxide and potassium hydroxide.
The alkaline earth metal hydroxide is calcium hydroxide, strontium hydroxide and barium hydroxide, preferably barium hydroxide.
The alkali metal salt is an alkali metal carbonate. The alkali metal carbonate is sodium carbonate, potassium carbonate, rubidium carbonate and cesium carbonate, and sodium carbonate and potassium carbonate are preferred.
More preferably, the alkaline aqueous solution is an aqueous sodium hydroxide solution.
In the method for treating epoxidation wastewater provided by the invention, the content of the alkaline compound in the alkaline aqueous solution is 1-60% by mass, preferably 10-50% by mass.
The invention provides an epoxidation wasteIn the water treatment method, preferably, the temperature for contact mixing of the epoxidation wastewater and the alkaline aqueous solution in the wastewater treatment reactor is 0-300 ℃, the pressure is 0.1-10.0 MPa, and the addition amount of the alkaline aqueous solution is 1-30 mass% of the amount of the wastewater; more preferably, the wastewater treatment reactor adopts a plug flow reactor, wherein the temperature of contact mixing is 0-300 ℃, the pressure is 0.1-10.0 MPa, and the hourly space velocity of the feeding liquid of the epoxidation wastewater is 0.1-20 h-1The volume space velocity of the alkaline aqueous solution is 0.01-0.5 h-1。
More preferably, the contact mixing temperature of the epoxidation wastewater and the alkaline aqueous solution in the wastewater treatment reactor is 50-250 ℃, the pressure is 0.1-5.0 MPa, and the hourly space velocity of the feeding liquid of the epoxidation wastewater is 0.3-15 h-1。
The following examples further illustrate the process of the present invention but are not intended to limit the invention thereto.
Example 1
In a 350mL stirred autoclave, 300.00g of the epoxidation wastewater having a 3-chloro-1, 2-propanediol content of 0.24 mass% and 8.43g of an aqueous sodium hydroxide solution having a sodium hydroxide content of 30 mass% were charged, respectively, and mixed at 100 ℃ and 0.1MPa with stirring for 1 hour, whereby 100.00% of the 3-chloro-1, 2-propanediol was converted into glycerol.
Example 2
The epoxidized wastewater was treated in the same manner as in example 1, except that the content of 3-chloro-1, 2-propanediol in the epoxidized wastewater was 0.49% by mass, the content of chloropropanediol monomethyl ether was 0.89% by mass, the amount of the aqueous sodium hydroxide solution was 12.18g, and the wastewater treatment temperature was 80 ℃. As a result of the treatment of the epoxidation wastewater, 100.00% of 3-chloro-1, 2-propanediol was converted into glycerol and 100.00% of chloropropanediol monomethyl ether was converted into glycerol monomethyl ether.
Example 3
Epoxidized wastewater was treated in the same manner as in example 1, except that the epoxidized wastewater had a 3-chloro-1, 2-propanediol content of 0.92 mass% and a chloropropanediol monomethyl ether content of 1.51 mass%, 10.28g of an alkaline aqueous solution having a potassium hydroxide content of 50 mass% was added, and the wastewater treatment temperature was 70 ℃. As a result of the treatment of the epoxidation wastewater, 100.00% of 3-chloro-1, 2-propanediol was converted into glycerol and 100.00% of chloropropanediol monomethyl ether was converted into glycerol monomethyl ether.
Example 4
Epoxidized wastewater was treated in the same manner as in example 3 except that 21.10g of an aqueous alkaline solution having a lithium hydroxide content of 20 mass% was added. As a result of the treatment of the epoxidation wastewater, 100.00% of 3-chloro-1, 2-propanediol was converted into glycerol and 100.00% of chloropropanediol monomethyl ether was converted into glycerol monomethyl ether.
Example 5
Epoxidized wastewater was treated in the same manner as in example 4 except that 81.58g of an aqueous alkaline solution having a barium hydroxide content of 10 mass% was added. As a result of the treatment of the epoxidation wastewater, 100.00% of 3-chloro-1, 2-propanediol was converted into glycerol and 100.00% of chloropropanediol monomethyl ether was converted into glycerol monomethyl ether.
Example 6
Epoxidized wastewater was treated in the same manner as in example 4 except that the epoxidized wastewater had a 3-chloro-1, 2-propanediol content of 0.57 mass% and a chloropropanediol monomethyl ether content of 0.81 mass%, and 16.97g of an alkaline aqueous solution having a sodium carbonate content of 30 mass% was added. As a result of the treatment of the epoxidation wastewater, the conversion of 3-chloro-1, 2-propanediol into glycerol was 93.19%, and the conversion of chloropropanediol monomethyl ether into glycerol monomethyl ether was 87.98%.
Example 7
Epoxidized wastewater was treated in the same manner as in example 4 except that 3-chloro-1, 2-propanediol content was 0.78 mass% and chloropropanediol monomethyl ether content was 0.96 mass%, and 22.10g of an alkaline aqueous solution containing 30 mass% of potassium carbonate was added. As a result of the treatment of the epoxidation wastewater, the conversion of 3-chloro-1, 2-propanediol into glycerin was 87.57%, and the conversion of chloropropanediol monomethyl ether into glycerol monomethyl ether was 86.21%.
Example 8
The epoxidation wastewater was treated in the same manner as in example 1 except that the treatment temperature of the epoxidation wastewater was 60 ℃ and the treatment result of the epoxidation wastewater was 81.05% in the conversion of 3-chloro-1, 2-propanediol into glycerol and 91.73% in the conversion of chloropropanediol monomethyl ether into glycerol monomethyl ether.
Example 9
Continuously treating the epoxidation wastewater in a jacketed pipe type reactor with the effective volume of 86mL, wherein the content of 3-chlorine-1, 2-propylene glycol in the epoxidation wastewater is 0.45 mass percent, the content of chloropropylene glycol monomethyl ether is 1.05 mass percent, and the feeding volume liquid hourly space velocity of the epoxidation wastewater is 13.95h-1The hourly space velocity of the feed solution of the 30 mass% aqueous sodium hydroxide solution was 0.22h-1The temperature of the jacket oil bath was kept constant at 240 ℃ and the pressure at the outlet of the reactor was kept constant at 4.3MPa, and after 1 hour of continuous feeding, a liquid sample at the outlet of the reactor was taken for analysis, and the pH of the liquid sample was 7, in which 3-chloro-1, 2-propanediol had been 100.00% converted to glycerol and chloropropanediol monomethyl ether had been 100.00% converted to glycerol monomethyl ether.
Example 10
Epoxidation waste water was continuously treated in the same manner as in example 9 except that the hourly space velocity of the feed solution of 30 mass% aqueous sodium hydroxide solution was 0.23h-1And as a result of the treatment of the epoxidation wastewater, the pH value of the epoxidation wastewater is 8-9, wherein the conversion rate of 3-chloro-1, 2-propanediol into glycerol is 100.00%, and the conversion rate of chloropropanediol monomethyl ether into glycerol monomethyl ether is 100.00%.
Example 11
Epoxidation waste water was continuously treated in the same manner as in example 9 except that the hourly space velocity of the feed solution of 30 mass% aqueous sodium hydroxide solution was 0.21 hr-1And as a result of the treatment of the epoxidation wastewater, the pH value of the epoxidation wastewater is 3-4, wherein the conversion rate of 3-chloro-1, 2-propanediol into glycerol is 100.00%, and the conversion rate of chloropropanediol monomethyl ether into glycerol monomethyl ether is 96.91%.
Example 12
By the use ofExample 9 the epoxidation wastewater was continuously treated in the same manner as in example 9 except that the hourly space velocity of the feed solution of the 30 mass% aqueous sodium hydroxide solution was 0.18h-1And as a result of the treatment of the epoxidation wastewater, the pH value of the epoxidation wastewater is 2-3, wherein the conversion rate of 3-chloro-1, 2-propanediol into glycerol is 100.00%, and the conversion rate of chloropropanediol monomethyl ether into glycerol monomethyl ether is 94.04%.
Example 13
The epoxidation wastewater was continuously treated in the same manner as in example 9 except that the content of 3-chloro-1, 2-propanediol in the epoxidation wastewater was 0.73% by mass, the content of chloropropanediol monomethyl ether was 1.61% by mass, and the feed volume liquid hourly space velocity of the epoxidation wastewater was 9.77h-1The hourly space velocity of the feed solution of 30% by mass aqueous sodium hydroxide solution was 0.28h-1And after 2 hours of continuous feeding, the pH value of the epoxidation wastewater is 13-14, wherein the conversion rate of 3-chloro-1, 2-propylene glycol into glycerol is 100.00%, and the conversion rate of chloropropanediol monomethyl ether into glycerol monomethyl ether is 100.00%.
Example 14
The epoxidation wastewater was continuously treated in the same manner as in example 9 except that the content of 3-chloro-1, 2-propanediol in the epoxidation wastewater was 0.53% by mass, the content of chloropropanediol monomethyl ether was 1.28% by mass, and the feed volume liquid hourly space velocity of the epoxidation wastewater was 4.88h-1The hourly space velocity of the feed solution of the 30 mass% aqueous sodium hydroxide solution was 0.14h-1The temperature of the jacket oil bath is constant at 150 ℃, the outlet pressure of the reactor is constant at 0.6MPa, and after 2 hours of continuous feeding, the pH value of the epoxidation wastewater is 13-14, wherein the conversion rate of 3-chloro-1, 2-propanediol into glycerol is 100.00%, and the conversion rate of chloropropanediol monomethyl ether into glycerol monomethyl ether is 100.00%.
Example 15
The epoxidized wastewater was continuously treated by the same method as in example 9, except that the content of 3-chloro-1, 2-propanediol in the epoxidized wastewater was 0.42 mass% and the content of chloropropanediol monomethyl ether was 1.02 mass%,the feed volume liquid hourly space velocity of the epoxidation wastewater is 0.489h-1The hourly space velocity of the feed solution of 30% by mass aqueous sodium hydroxide solution was 0.014h-1The temperature of the jacket oil bath is constant at 60 ℃, the outlet pressure of the reactor is constant at 0.1MPa, and after continuous feeding is carried out for 6 hours, the pH value of the epoxidation wastewater is 13-14, the conversion rate of 3-chloro-1, 2-propylene glycol into glycerol is 100.00%, and the conversion rate of chloropropanediol monomethyl ether into glycerol monomethyl ether is 94.83%.
The mode of the present invention has been described in detail above, but the present invention is not limited to the specific details of the above-described embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.