CN1594265A - Preparation method of gluconic acid and its salt - Google Patents

Abstract

The invention relates to a preparation method of gluconic acid and its salts. Calcium gluconate was synthesized by liquid-phase catalytic oxidation of glucose with Au/C catalyst and neutralized by calcium hydroxide. On this basis, the corresponding gluconate is obtained through the replacement reaction of magnesium, zinc and ferrous sulfate, and gluconic acid is obtained through the replacement reaction of sulfuric acid. The invention is used to produce gluconic acid and its salts and has the characteristics of low production cost, high production efficiency and simple process flow.

Description

Preparation method of gluconic acid and its salts

technical field

The invention relates to a preparation method of gluconic acid and its salts, in particular to a preparation method of gluconic acid and its calcium salt, magnesium salt, zinc salt, ferrous salt and the like.

Background technique

Gluconic acid and its salts are important organic chemical products with multiple uses. They can be used as food additives and nutritional supplements, complexing agents, cleaning agents for glass and steel surfaces, washing aids, etc., and are widely used in the fields of food, medicine, electroplating, construction, textiles, and daily chemicals. For example: (1) Calcium gluconate is a calcium preparation, which is mainly used clinically for calcium supplementation and treatment of various diseases caused by calcium deficiency. It can promote the calcification of bones and teeth, maintain the normal excitability of neuromuscular, reduce capillary permeability, increase the contractility of capillary wall; prevent calcium deficiency such as tetany, bone hypoplasia, rickets and tuberculosis, pregnancy and breastfeeding Calcium salt supplementation for period women. (2) Zinc gluconate can dissociate into zinc ions and gluconic acid in the human body. They participate in the synthesis of ribonucleic acid and deoxyribonucleic acid, which can promote wound healing, growth and development, and the normal function of zinc-containing enzymes in the body. It is used to treat children's growth retardation, malnutrition, anorexia, pica, oral ulcers, acne and other diseases caused by zinc deficiency. (3) Magnesium gluconate is a new type of magnesium supplement in gluconate products developed in recent years. Magnesium is an essential macroelement for the human body and has important physiological functions. For example, magnesium and phosphorus form bone salt; Magnesium is an indispensable activator of phosphorylation and some enzyme systems in the body. Magnesium sulfate has been used clinically as a magnesium supplement for a long time. It has the advantages of small side effects, high bioavailability and good absorption rate, and is a good magnesium supplement. However, as an inorganic compound, it is gradually being replaced by a new type of magnesium supplement—magnesium gluconate. Magnesium supplements—see the standard of gluconic acid in the United States F.C.CIII. (4) Ferrous gluconate is a good iron supplement for the treatment of iron deficiency anemia. Because iron is an important component of hemoglobin and an activator of redox enzymes. Iron deficiency can cause iron deficiency anemia. Especially children with iron deficiency lead to anemia more. (5) Sodium gluconate has excellent chelating properties, and has been widely used in metal anticorrosion, water scale inhibition, metal surface treatment, electroplating, etc. Especially as a water treatment agent for circulating cooling water systems of petroleum and chemical enterprises, low-pressure boilers, and internal combustion engine cooling water systems, the annual consumption is very large.

At present, the main methods of industrial production of gluconic acid and its salts at home and abroad are: biological fermentation method: using bacteria or oxidase to oxidize glucose into gluconic acid. This method takes a long time to ferment, the color of the product is difficult to control, the conversion rate is low, and the requirements for the aseptic degree of the production environment are high.

Homogeneous chemical oxidation method: mainly refers to sodium hypochlorite oxidation method and hydrogen peroxide oxidation method. This method has many by-products, difficult separation of products, and low yield.

Electrolytic oxidation method: This method is to add a certain concentration of glucose solution and a suitable electrolyte in the electrolytic cell, and conduct constant current electrolysis at a certain temperature and current density. This method consumes a lot of energy in industrial production, and the conditions are not easy to control.

Heterogeneous catalytic oxidation method: This method has the advantages of simple process, mild reaction conditions (various gas-liquid-solid three-phase mixed reactors can be used under normal pressure, and the reaction temperature is generally controlled below 60°C), and the reaction time Short, high conversion rate, less waste, easy to handle the product and so on. The catalyst generally uses a platinum group metal catalyst, for example, a patent (GB 1208101, JP8007230, JP 7652121, JP5872538) for catalytic oxidation of glucose using catalysts such as Pt/C and Pd/C has been announced. In addition, there are also patents for modifying Pt/C or Pd/C with base metals such as Bi and Pb and applying them to this catalytic oxidation reaction (US Patent 5132452, US Patent 4843173, DE-OS2936652). However, the noble metal consumption of the Pt/C or Pd/C catalyst used in the heterogeneous catalytic oxidation method is large, resulting in high production costs, and the oxidation selectivity of the Pt/C or Pd/C catalyst is poor and easy to be poisoned, and its failure The precious metals in the catalyst are difficult to recover.

Contents of the invention

Purpose one of the present invention is to provide a kind of easy and convenient method for preparing gluconate of calcium, magnesium, zinc, ferrous etc.

The second object of the present invention is to provide a kind of easy gluconic acid preparation method

Adopt following sequential technology to realize above-mentioned invention object one:

① Mix the powdery activated carbon loaded with gold particles, that is, the Au/C catalyst, with the aqueous glucose solution, and keep the temperature of the resulting mixed solution at 40°C to 55°C;

2. Pass 40～1000 milliliters/minute oxygen or air into step 1. gained mixture, add Ca(OH) ₂ aqueous solution under stirring;

③Traditional process means such as suction filtration, concentration, crystallization, air-drying, etc. to process step ②The obtained solution obtains the corresponding gluconate.

In the selection step ①, the particle size of gold particles is 5-15nm, the specific surface area of activated carbon is 800-1500m ² /g, the particle size of activated carbon is 100-400 mesh, and the mass ratio of gold particles: activated carbon is 0.5-3:100.

In the selection step ①, the percentage weight concentration of the glucose aqueous solution is 1-20%, and the gold particle: glucose mass ratio is 1:500-3000.

The pH value of the solution obtained in step ② is preferably 8-9.

Add sulfate to the solution obtained in step ② to obtain other corresponding salts.

Above-mentioned sulfate can be any one of zinc sulfate, magnesium sulfate or ferrous sulfate.

Preferred sulfate: the molar ratio of calcium gluconate contained in the solution obtained in step ② is 1:1.

The preparation method of gluconic acid of the above-mentioned invention object two, comprises the following processing steps successively:

① Mix the powdered activated carbon loaded with gold particles and the aqueous glucose solution, and keep the temperature of the resulting mixed solution at 40°C to 55°C;

2. Pass 400～1000 milliliters/minute oxygen or air into step 1. gained mixture, add Ca(OH) ₂ aqueous solution under stirring;

③ Add sulfuric acid to the mixture obtained in step ②, heat in a water bath at 60° C. to 90° C. for 1 to 3 hours, and obtain a gluconic acid solution through subsequent conventional processing.

For the process parameters of technical scheme two, the following optimal adjustments can be made:

Preferred step 1. The particle size of the gold particles is 5-15nm, the specific surface area of the activated carbon is ^800-1500m2 /g, the particle size of the activated carbon is 100-400 mesh, the mass ratio of gold particles: the activated carbon=0.5-3:100, gold particles: glucose Mass ratio=1:500～3000, the pH value of the solution obtained in step ② is 8～9.

Preferred step 3. sulfuric acid: step 2. calcium gluconate mol ratio contained in the solution gained=1:1.

The Au/C catalyst used in the above two technical schemes is prepared by the following sequential process technology:

(1) Use ultraviolet light with a wavelength of 254 nanometers or 300 nanometers and a total radiation intensity of 0.5 to 1 cal/m ² sec to irradiate any one of HAuCl ₄ or AuCl ₃ with a molecular weight of 400, 600, or 1000 Any mixed aqueous solution of polyethylene glycol and acetone for 15 to 25 minutes to obtain a gold colloidal solution. Wherein, the molar ratio of Au(III) ions in HAuCl ₄ or AuCl ₃ : polyethylene glycol: acetone = 4.88×10 ^-4 : 11.28×10 ^-2 :1.

(2) Under stirring conditions, the activated carbon is immersed in the gold colloidal solution obtained in step (1).

In above-mentioned technical scheme one, use supersaturated Ca (OH) _Aqueous solution, i.e. aqueous lime milk solution, helps to accelerate reaction process. In addition, sodium gluconate can be obtained by using the same process as the above calcium gluconate preparation process.

The invention utilizes Au/C catalyst to catalyze and oxidize glucose in one-step liquid phase to synthesize calcium gluconate, and thereby prepare gluconic acid and other salts, such as zinc gluconate, magnesium gluconate, ferrous gluconate and the like. Compared with the biofermentation method and the heterogeneous catalytic oxidation method using catalyzers such as Pt/C and Pd/C, the glucose liquid-phase catalytic oxidation reaction of the Au/C catalyst of the present invention has the following characteristics: (1) ) The Au content in the catalyst is 1/3～1/5 of the Pt or Pd content in catalysts such as Pt/C, Pd/C, and the calcium reagent raw material is cheap, thereby can reduce the production cost of the present invention. (2) The Au/C catalyst has higher catalytic activity and oxidation selectivity, is less likely to be poisoned, and has a longer catalytic life, which is conducive to improving the production efficiency of the present invention. (3) Gold is a biocompatible element. During the production process, trace or ultra-trace amounts of gold are lost into the product and used for food or medicine, which will not cause harm to the human body, but will have a good effect (Haruta M. Gold Bulletin, 2001, Vol. 34, p. 40). (4) The technical process of the invention is simple and convenient, and has no pollution.

Taking zinc sulfate as example, the reaction formula of calcium gluconate of the present invention and magnesium, zinc, ferrous sulfate is as follows:

 

In addition, after gluconic acid is obtained by the present invention, it can also be used as an intermediate to obtain magnesium, zinc, and ferrous gluconate.

The purity of the reagents used in the present invention are commercially available products of analytical grade.

Detailed ways

Example 1:

Preparation of Calcium Gluconate

In the liquid phase reaction vessel, according to the mass ratio of glucose and Au in the Au/C catalyst is 500:1, the glucose aqueous solution and the Au/C catalyst are mixed, the concentration of the glucose aqueous solution is 1% by weight, and the temperature of the reaction system is 40°C , feed 400ml/min oxygen, add milk of lime (Ca(OH) ₂ ) aqueous solution under constant stirring, keep the pH value of the reaction solution at 8, until the pH value of the reaction solution remains unchanged for 20min, and the reaction ends at this time. Then the solution is filtered by suction, concentrated under reduced pressure, crystallized, and air-dried to obtain the product calcium gluconate.

Example 2:

Preparation of Calcium Gluconate

In the liquid phase reaction vessel, the mass ratio of glucose and Au in the Au/C catalyst is 1500:1, the glucose aqueous solution and the Au/C catalyst are mixed, the concentration of the glucose aqueous solution is 10% by weight, and the temperature of the reaction system is 45°C , feed 600ml/min oxygen, add milk of lime (Ca(OH) ₂ ) aqueous solution under constant stirring, keep the pH value of the reaction solution at 8.5, until the pH value of the reaction solution remains unchanged for 20min, then the reaction ends. Then the solution is filtered by suction, concentrated under reduced pressure, crystallized, and air-dried to obtain the product calcium gluconate.

Example 3:

Preparation of Calcium Gluconate

In the liquid phase reaction vessel, according to the mass ratio of glucose and Au in the Au/C catalyst is 3000:1, the glucose aqueous solution and the Au/C catalyst are mixed, the concentration of the glucose aqueous solution is 20% by weight, and the temperature of the reaction system is 55°C , feed 1000ml/min air, add milk of lime (Ca(OH) ₂ ) aqueous solution under constant stirring, keep the pH value of the reaction solution at 9, until the pH value of the reaction solution remains unchanged for 20min, then the reaction ends. Then the solution is filtered by suction, concentrated under reduced pressure, crystallized, and air-dried to obtain the product calcium gluconate.

Example 4:

Preparation of salts such as zinc, magnesium or ferrous gluconate

Taking the preparation of zinc gluconate as an example, the calcium gluconate solution prepared in any one of Examples 1, 2 or 3 is mixed with the zinc sulfate solution, calcium gluconate: zinc sulfate molar ratio=1:1, and heated for reaction. After the reaction is completed, the calcium sulfate precipitate is filtered out while it is hot, and then the filtrate is concentrated under reduced pressure, crystallized, and air-dried to obtain zinc gluconate.

The preparation of gluconate products such as magnesium gluconate and ferrous gluconate is the same as the above-mentioned zinc gluconate preparation process.

Example 5:

production of gluconic acid

Adjust 0.5 mol of calcium gluconate obtained in Example 1 into an aqueous solution, place it in a suitable reaction vessel, slowly add 0.5 mol of concentrated sulfuric acid under stirring, and heat and react in a water bath at 60° C. for 1.5 h. Filtrate the precipitated calcium sulfate precipitate while it is hot. After the filtrate is cooled, it flows through the exchange column of anion and cation exchange resins at an appropriate flow rate to obtain a high-purity gluconic acid solution.

Embodiment 6:

production of gluconic acid

Adjust 1 mol of calcium gluconate prepared in Example 2 into an aqueous solution, place it in a suitable reaction vessel, slowly add 1 mol of concentrated sulfuric acid under stirring, and heat and react in a water bath at 80°C for 1 h. Filter the precipitated calcium sulfate precipitate while it is hot, cool the filtrate, and purify the obtained gluconic acid with barium hydroxide and oxalic acid as precipitants to remove a small amount of SO ₄ ^2- and Ca ²⁺ , and excess Ba ²⁺ and oxalic acid The resulting barium oxalate precipitate was removed to obtain a high-purity gluconic acid solution.

Embodiment 7:

production of gluconic acid

Adjust 1.5 mol of calcium gluconate obtained in Example 3 into an aqueous solution, place it in a suitable reaction vessel, slowly add 1.5 mol of concentrated sulfuric acid under stirring, and heat and react in a water bath at 90° C. for 3 hours. Filtrate the precipitated calcium sulfate precipitate while it is hot. After the filtrate is cooled, it flows through the exchange column of anion and cation exchange resins at an appropriate flow rate to obtain a high-purity gluconic acid solution.

Embodiment 8:

Preparation of Zinc and Magnesium Gluconate Using Gluconic Acid as Intermediate

Zinc gluconate: adjust the gluconic acid solution obtained in Example 5 to a concentration of 0.1mol/L, add 0.05mol zinc oxide solid powder in batches under stirring in a water bath at 60°C, adjust the pH to less than 6, and react for 5 hours until the solution becomes transparent state. After filtration, the filtrate was concentrated under reduced pressure to about 1/3 of the original volume. Add 10ml of absolute ethanol and let it stand for about 8 hours to fully crystallize. Vacuum dried to obtain white crystalline zinc gluconate powder.

Magnesium gluconate: adjust the gluconic acid solution obtained in Example 6 to a concentration of 0.1mol/L, add 0.05mol magnesium oxide solid powder in batches under stirring in a water bath at 65°C, adjust the pH to less than 6, and react for 2 hours until the solution is transparent . After filtration, the filtrate was concentrated under reduced pressure to about 1/3 of the original volume. Add 10ml of absolute ethanol and let it stand for 9h to fully crystallize. Vacuum dried to obtain white crystalline magnesium gluconate powder.

Embodiment 9:

Preparation of sodium gluconate

In the liquid phase reaction vessel, the mass ratio of glucose and Au in the Au/C catalyst is 2000:1, the glucose aqueous solution and the Au/C catalyst are mixed, the concentration of the glucose aqueous solution is 5% by weight, and the temperature of the reaction system is 50°C , feed 800ml/min air, add Na(OH) aqueous solution under constant stirring, make the pH value of the reaction solution maintain at 8, until the pH value of the reaction solution remains unchanged for 10min, the reaction ends at this time. Then the solution is filtered by suction, concentrated under reduced pressure, crystallized, and air-dried to obtain the product sodium gluconate.

Claims (10)

1. gluconate preparation method comprises following process steps successively:

The powdered active carbon that 1. will be loaded with gold grain mixes with D/W, and keeping the temperature of gained mixing solutions is 40 ℃～55 ℃;

2. to step 1. the gained mixture feed 400～1000 ml/min oxygen or air, stir and add Ca (OH) down ₂The aqueous solution;

3. suction filtration, concentrate, crystallization, traditional technology means treatment step such as air-dry 2. gained solution obtain corresponding gluconate.

2. the gluconate preparation method of claim 1, it is characterized in that step 1. the granularity of described gold grain be 5～15nm, the specific surface area 800～1500m of described gac ²/ g, granularity 100～400 orders of described gac, described gold grain: described gac (mass ratio)=0.5～3: 100.

3. the gluconate preparation method of claim 1 is characterized in that the 1. described D/W weight percent concentration 1～20% of step, described gold grain: glucose (mass ratio)=1: 500～3000.

4. the gluconate preparation method of claim 1, it is characterized in that step 2. the pH value of gained solution be 8～9.

5. claim 1,2,3, one of 4 gluconate preparation method is characterized in that 2. adding vitriol in the gained solution to step.

6. the gluconate preparation method of claim 5 is characterized in that described vitriol is any of zinc sulfate, sal epsom or ferrous sulfate.

7. the gluconate preparation method of claim 6 is characterized in that described vitriol: the calglucon (mol ratio) that 2. step contains in the gained solution=1: 1.

8. gluconic acid preparation method comprises following process steps successively:

The powdered active carbon that 1. will be loaded with gold grain mixes with D/W, and keeping the temperature of gained mixing solutions is 40 ℃～55 ℃;

2. to step 1. the gained mixture feed 400～1000 ml/min oxygen or air, stir and add Ca (OH) down ₂The aqueous solution;

3. 2. add sulfuric acid in the gained mixture to step, 60 ℃～90 ℃ heating in water bath 1～3 hour handle to obtain gluconic acid solution through follow-up traditional technology.

9. the gluconic acid preparation method of claim 8, it is characterized in that step 1. the granularity of described gold grain be 5～15nm, the specific surface area 800～1500m of described gac ²/ g, granularity 100～400 orders of described gac, described gold grain: described gac (mass ratio)=0.5～3: 100, described gold grain: glucose (mass ratio)=1: 500～3000, step 2. the pH value of gained solution are 8～9.

10. the gluconic acid preparation method of claim 9 is characterized in that the 3. described sulfuric acid of step: the calglucon (mol ratio) that 2. step contains in the gained solution=1: 1.