Boracic acid recovery and reutilization method in lactulose preparation

Abstract

The invention discloses a boracic acid recovery and reutilization method in the lactulose preparation process. The method mainly comprises the steps of (1) performing nanofiltration on an isomerized lactulose solution for removing salts and boracic acid; (2) concentrating, crystallizing and drying nanofiltration permeate liquid to obtain boracic acid crystals; and (3) adding the boracic acid crystals back into the lactulose solution as a catalyst; and performing an isomerization reaction. The method provided by the invention has the advantages that the removal rate of the boracic acid in the isomerized solution through nanofiltration reaches 98 percent or higher; after the crystallization treatment, the boracic acid can be recovered and reused again; the recovery and reutilization rate is higher than 85 percent; the operation process is simple; the industrialization can be easily realized; meanwhile, the production cost is greatly reduced; the step of treating a large amount of boron-containing water is omitted; the sewage discharge quantity is reduced; and a better environment-friendly effect is achieved.

Description

technical field

[0001] The invention relates to a method for recovering and reusing boric acid in the preparation of lactulose. Background technique

[0002] Lactulose, also known as isomerized lactose or lactulose, is a synthetic disaccharide that generally does not exist in nature. It is about 48-70% sweeter than sucrose.

[0003] Lactulose is a promoter of bifidobacteria, and can also promote the synthesis of multi-ethnic vitamins and the absorption of various trace elements by the human body. In addition, lactulose improved lipid metabolism, decreased total serum cholesterol concentration, and increased the proportion of high-density lipoprotein in serum. And low-calorie lactulose will not cause dental caries, which can meet the requirements of those who love desserts and worry about gaining weight to the greatest extent. It is precisely because of the various excellent physiological and functional properties of lactulose that lactulose is widely used in many fields s...

Examples

Embodiment 1

[0022] A method for recovering and reusing boric acid in the preparation of lactulose, comprising the following steps:

[0023] (1) The pH of the lactulose solution obtained by isomerization is adjusted to about 2.5, the whole solution is acidic, the lactulose-borate complex is decomposed to generate lactulose and borate, and the borate is converted to boric acid under acidic conditions. exists in the form of;

[0024] (2) The feed liquid obtained in step (1) is separated and purified by a nanofiltration membrane, the molecular weight cut off of the nanofiltration membrane is 200-300 Da, the operating pressure of the nanofiltration membrane is controlled at 15 bar, the temperature is controlled at 30 ° C, and the boric acid in the retentate is removed. rate of 98.2%;

[0025] (3) Concentrate the permeate after the membrane to a solid content of 32%, and adjust the pH of the solution to 3.7;

[0026] (4) The solution in step (3) is cooled and crystallized, and the cooling int...

Embodiment 2

[0030] A method for recovering and reusing boric acid in the preparation of lactulose, comprising the following steps:

[0031] (1) The pH of the lactulose solution obtained by isomerization is adjusted to about 2.8, the whole solution is acidic, the lactulose-borate complex is decomposed to generate lactulose and borate, and the borate is converted to boric acid under acidic conditions. exists in the form of;

[0032] (2) Separating and purifying the feed liquid obtained in step (1) through a nanofiltration membrane, the molecular weight cut-off of the nanofiltration membrane is 200-300 Da, the operating pressure of the nanofiltration membrane is controlled at 30 bar, the temperature is controlled at 40 ° C, and the boric acid in the retentate is removed. rate of 98.2%;

[0033] (3) Concentrate the permeate after the membrane to a solid content of 35%, and adjust the pH of the solution to 5.0;

[0034] (4) The solution in step (3) is cooled and crystallized, and the cooling...

Embodiment 3

[0038] A method for recovering and reusing boric acid in the preparation of lactulose, comprising the following steps:

[0039] (1) The pH of the lactulose solution obtained by isomerization is adjusted to about 3.0, the whole solution is acidic, the lactulose-borate complex is decomposed, and lactulose and borate are generated. exists in the form of;

[0040] (2) Separating and purifying the feed liquid obtained in step (1) by a nanofiltration membrane, the molecular weight cut-off of the nanofiltration membrane is 200-300 Da, the operating pressure of the nanofiltration membrane is controlled at 25 bar, the temperature is controlled at 50 °C, and the boric acid in the retentate is removed. rate of 98.1%;

[0041] (3) Concentrate the permeate after the membrane to a solid content of 30%, and adjust the pH of the solution to 3.0;

[0042] (4) The solution in step (3) is cooled and crystallized, and the cooling interval is 75°C→10°C, crystallized for 15 hours, and the crystal...

technical field

[0001] The invention relates to a method for recovering and reusing boric acid in the preparation of lactulose. Background technique

[0002] Lactulose, also known as isomerized lactose or lactulose, is a synthetic disaccharide that generally does not exist in nature. It is about 48-70% sweeter than sucrose.

[0003] Lactulose is a promoter of bifidobacteria, and can also promote the synthesis of multi-ethnic vitamins and the absorption of various trace elements by the human body. In addition, lactulose improved lipid metabolism, decreased total serum cholesterol concentration, and increased the proportion of high-density lipoprotein in serum. And low-calorie lactulose will not cause dental caries, which can meet the requirements of those who love desserts and worry about gaining weight to the greatest extent. It is precisely because of the various excellent physiological and functional properties of lactulose that lactulose is widely used in many fields s...

Examples

Embodiment 1

[0022] A method for recovering and reusing boric acid in the preparation of lactulose, comprising the following steps:

[0023] (1) The pH of the lactulose solution obtained by isomerization is adjusted to about 2.5, the whole solution is acidic, the lactulose-borate complex is decomposed to generate lactulose and borate, and the borate is converted to boric acid under acidic conditions. exists in the form of;

[0024] (2) The feed liquid obtained in step (1) is separated and purified by a nanofiltration membrane, the molecular weight cut off of the nanofiltration membrane is 200-300 Da, the operating pressure of the nanofiltration membrane is controlled at 15 bar, the temperature is controlled at 30 ° C, and the boric acid in the retentate is removed. rate of 98.2%;

[0025] (3) Concentrate the permeate after the membrane to a solid content of 32%, and adjust the pH of the solution to 3.7;

[0026] (4) The solution in step (3) is cooled and crystallized, and the cooling int...

Embodiment 2

[0030] A method for recovering and reusing boric acid in the preparation of lactulose, comprising the following steps:

[0031] (1) The pH of the lactulose solution obtained by isomerization is adjusted to about 2.8, the whole solution is acidic, the lactulose-borate complex is decomposed to generate lactulose and borate, and the borate is converted to boric acid under acidic conditions. exists in the form of;

[0032] (2) Separating and purifying the feed liquid obtained in step (1) through a nanofiltration membrane, the molecular weight cut-off of the nanofiltration membrane is 200-300 Da, the operating pressure of the nanofiltration membrane is controlled at 30 bar, the temperature is controlled at 40 ° C, and the boric acid in the retentate is removed. rate of 98.2%;

[0033] (3) Concentrate the permeate after the membrane to a solid content of 35%, and adjust the pH of the solution to 5.0;

[0034] (4) The solution in step (3) is cooled and crystallized, and the cooling...

Embodiment 3

[0038] A method for recovering and reusing boric acid in the preparation of lactulose, comprising the following steps:

[0039] (1) The pH of the lactulose solution obtained by isomerization is adjusted to about 3.0, the whole solution is acidic, the lactulose-borate complex is decomposed, and lactulose and borate are generated. exists in the form of;

[0040] (2) Separating and purifying the feed liquid obtained in step (1) by a nanofiltration membrane, the molecular weight cut-off of the nanofiltration membrane is 200-300 Da, the operating pressure of the nanofiltration membrane is controlled at 25 bar, the temperature is controlled at 50 °C, and the boric acid in the retentate is removed. rate of 98.1%;

[0041] (3) Concentrate the permeate after the membrane to a solid content of 30%, and adjust the pH of the solution to 3.0;

[0042] (4) The solution in step (3) is cooled and crystallized, and the cooling interval is 75°C→10°C, crystallized for 15 hours, and the crystal...