How is bes buffer synthesized

Details:

Dihydroxyethyl aminoethanesulfonic acid bes is mainly used as a biological buffer. Its structure is similar to that of bicine. Aminoacetic acid is replaced by aminoethanesulfonic acid. It also has amphoteric properties and is used as a pH buffer in biochemical detection. This paper discusses the synthetic route of BES.

Physicochemical properties of BES buffer:

Chinese Name: bes, N, N-bis (2-hydroxyethyl) - 2-aminoethanesulfonic acid; N. N - (2-hydroxyethyl) - 2-aminoethanesulfonic acid; N. N-bis (2-hydroxyethyl) - 2-aminoethanesulfonic acid, 2 - (diethanolamino) ethanesulfonic acid

BES buffer

English Name: n, N-bis (2-hydroxyethyl) taurine

Purity: ≥ 99%

CAS No.: 10191-18-1

Molecular formula: c6h15no5s

Molecular weight: 213.20

useful pH range： 6.4 - 7.8

pKa：（25 °C） 7.1

Appearance: white crystalline powder

BES synthesis route

The raw materials are diethanolamine, sodium 2-chloroethyl sulfonate and sodium hydroxide, all of which are analytical pure reagents. Diethanolamine reacts with sodium chloroethanesulfonate in the presence of sodium hydroxide to form bes sodium salt, and then acidified with acid,

BES can be generated. According to the measurement, diethanolamine and sodium hydroxide are added into a four port flask with the same amount of sodium hydroxide and sodium chloroethanesulfonate. The flask is equipped with a thermometer, pH meter and stirrer. At a certain temperature, add sodium 2-chloroethanesulfonate aqueous solution gradually to the flask, control the feeding time and amount, and keep the temperature for reaction for a period of time after completion. The reaction end point is determined according to the pH change of the system. After the reaction, add acid acidification, distill under reduced pressure, and remove excess water and unreacted diethanolamine to obtain crude bes. After refining and drying the crude product, the finished bes product can be obtained.

When diethanolamine reacts with sodium chloroethanesulfonate, it will produce bes sodium salt and hydrochloric acid, which need to be neutralized by sodium hydroxide. The effect of temperature on the reaction is not obvious. With the extension of reaction time, the pH value of the system changes obviously. At the initial stage of the reaction, the pH value of the system decreases sharply, and then the downward trend of pH value slows down. After 60 minutes, the reaction is close to the end point. In BES synthesis, strictly control the ratio of reaction materials (1:1.1), the temperature is between 60-80 ℃ and the reaction time is 60 minutes.

Here is a synthetic route of buffer bes. If it is mass produced in industry, there are other synthetic routes according to the cost of raw materials. Desheng is a manufacturer of biological buffers, which can supply Tris, bicine, BES and other buffers.