The summary and comparation for synthesis of HEPES

4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) is a hydrogen ion buffer which has a good buffering capacity in the pH range of 6.8~8.2 and can control a constant pH for a long time. The commonly used concentration is 10~50mmol/L, the general culture solution contains 20mmol/L HEPES can have a good buffer capacity. Then how to prepare it?


1. CN104803949A
(1) addition reaction of vinyl sulfonic acid or vinyl sulfonate with N-hydroxyethylpiperazine to prepare 4-hydroxyethylpiperazine Ethane sulfonate;
(2) using an acidifying agent to convert 4-hydroxyethylpiperazineethanesulfonate to 4-hydroxyethylpiperazineethanesulfonic acid and a salt of the corresponding acidifying agent to obtain an acidified mother liquor;
(3) the acidified mother liquor is crystallized to remove the salt of the corresponding acidifying agent to obtain the acidified mother liquor after the treatment;
(4) a soluble barium salt or a calcium salt is added to the acidified mother liquor to remove residual sulfate, and concentrated by evaporation to obtain a primary purification product of HEPES;
(5) The primary purified product is washed with a small molecular weight alcohol, and dried to obtain high purity HEPES.
The method not only can produce HEPES in high purity, but also has low purification cost, simple process, easy operation and no pollution.
2. CN104876892A
(1) condensation reaction of 2-hydroxyethylsulfonic acid or 2-hydroxyethylsulfonate with N-hydroxyethylpiperazine to obtain 4-hydroxyethyl Piperazine ethyl sulfonate;
(2) using an acidifying agent to convert 4-hydroxyethylpiperazineethanesulfonate to 4-hydroxyethylpiperazineethanesulfonic acid and a salt of the corresponding acidifying agent to obtain an acidified mother liquor;
(3) the acidified mother liquor is diluted with deionized water to 1~10 wt.%, and salt of the corresponding acidifying agent is removed by nanofiltration, and concentrated by evaporation to obtain a crude HEPES;
(4) The crude HEPES was washed and dried to obtain high-purity HEPES.

The method not only can produce HEPES with high purity, but also has low production cost, simple process, easy operation and high yield.


3. CN106905262A
(1) 2-hydroxyethylsulfonic acid or 2-hydroxyethylsulfonate and N-hydroxyethylpiperazine are subjected to a condensation reaction to obtain 4-hydroxyethylpiperazineethanesulfonate;
(2) adding an acidifying agent to 4-hydroxyethylpiperazineethanesulfonate, converting it to 4-hydroxyethylpiperazineethanesulfonic acid and a salt corresponding to the acidifying agent to obtain an acidified mother liquor;
(3) The acidified mother liquor is diluted with deionized water to a solution of 10-15wt.%, and extracted by a five-stage continuous countercurrent centrifugal extractor to extract a raffinate and extract an organic phase, the raffinate is aqueous solution of product and inorganic salt.
(4) the extracted organic phase is treated with reverse extraction, and recover the extracting agent, obtain impurities and by-products;
(5) the salt of the corresponding acidifying agent in raffinate in step 3 is removed with a nanofiltration membrane, and concentrated by evaporation to obtain a HEPES;
(6) Finally, the 4-hydroxyethylpiperazineethanesulfonic acid product was washed with absolute ethanol and dried to obtain high-purity HEPES.

The HEPES obtained by the invention has high purity, simple operation process, environmental protection process, low purification cost and high yield, which is suitable for industrial mass production.


4. CN108003117A

(1) adding a sodium sulfate solution with a mass fraction of 3%~5% in the anode chamber and the cathode chamber, and adding a sodium hydroxyethylpiperazine ethylsulfonate solution with a mass concentration of 10% to 30% in the liquid chamber, add pure water in the alkali chamber;
(2) Passing DC power supply for voltage regulation operation, control voltage is 15~25V, control current density is 10~20mA/cm2, device operating temperature is 20~35°C, flow control of each compartment is 30~40L/h, during the process of device operation, each compartment is circulated and cooled by the chilled brine in the circulating coil;
(3) Sampling and analyzing the solution in the alkali chamber and the liquid chamber at regular intervals. When the concentration of the solution in the alkali chamber is maintained, the device stops running, and finally the solution of HEPES is obtained, which was evaporated to obtain a solid crystal of HEPES.


HEPES obtained by the method satisfies the requirement of high purity, and can also recover the alkali liquor, thereby effectively avoiding the pollutant discharge and realizing the resource-saving utilization.


Edited by Suzhou Yacoo Science Co., Ltd.