Sodium gluconate is a chemical agent, which is widely used in construction, textile, water treatment and other industries. It can be used as cleaning agent, cement admixture, retarder, water reducer, water quality stabilizer and food additive. As its use becomes more and more important, more and more people want to make sodium gluconate. What are the methods to make sodium gluconate?

1.生物發(fā)酵法。該方法包括真菌發(fā)酵和細菌發(fā)酵，另外還有固定細胞發(fā)酵工藝，其中較普遍采用的是黑曲霉菌發(fā)酵制葡萄糖酸鈉工藝。該方法具有發(fā)酵速度快、發(fā)酵過程易于控制、產(chǎn)品易提取等特點，但同時也會出現(xiàn)產(chǎn)品色澤不易控制、無菌化要求程度高等不良現(xiàn)象。

1. Biological fermentation. The method includes fungal fermentation and bacterial fermentation, as well as fixed cell fermentation process, in which Aspergillus niger fermentation for sodium gluconate is widely used. This method has the characteristics of fast fermentation speed, easy control of fermentation process and easy extraction of products, but at the same time, it will also have adverse phenomena such as difficult control of product color and high aseptic requirements.

2.均相化學氧化法。結(jié)晶葡萄糖加水溶解后加入催化劑，控制一定的溫度，滴加次氯酸鈉溶液，同時滴加離子膜液堿來控制反應(yīng)體系的pH值，使平衡向生成葡萄糖酸鈉的方向移動。使用該方法生產(chǎn)葡萄糖酸鈉具有轉(zhuǎn)化率高，工藝過程簡單，成本低的優(yōu)點，但是其中間步驟多，副產(chǎn)物多，產(chǎn)物難于分離，因此在應(yīng)用上受到了限制。

2. Homogeneous chemical oxidation. After the crystalline glucose is dissolved with water, the catalyst is added, the temperature is controlled, the sodium hypochlorite solution is added dropwise, and the ionic membrane liquid alkali is added dropwise to control the pH value of the reaction system, so as to move the balance to the direction of generating sodium gluconate. The production of sodium gluconate by this method has the advantages of high conversion, simple process and low cost, but it has many intermediate steps, many by-products and difficult to separate the products, so its application is limited.

3.電解氧化法。該方法是在電解槽中加入一定濃度的葡萄糖溶液，再加入適宜的電解質(zhì)，在一定溫度、一定電流密度下恒電流電解。其工業(yè)參數(shù)的確定因加入電解質(zhì)的不同而異。電解氧化法雖然克服了生物發(fā)酵法和均相化學氧化法的某些缺點，但在工業(yè)生產(chǎn)中能耗大，不易控制，因此工業(yè)化生產(chǎn)中很少采用。

3. Electrolytic oxidation method. The method is to add a certain concentration of glucose solution into the electrolytic cell, then add a suitable electrolyte, and conduct constant current electrolysis at a certain temperature and current density. The determination of industrial parameters varies with the addition of electrolytes. Although electrolytic oxidation method overcomes some shortcomings of biological fermentation method and homogeneous chemical oxidation method, it is rarely used in industrial production because of its high energy consumption and difficult to control.

4.多相催化氧化法。配制一定量的葡萄糖溶液加入于四口燒瓶中，稱取適量催化劑加入到此燒瓶中，恒溫。該法工藝簡單，反應(yīng)平穩(wěn)，易于控制，反應(yīng)條件溫和，其葡萄糖轉(zhuǎn)化率在95%左右。

4. Heterogeneous catalytic oxidation. Prepare a certain amount of glucose solution and add it into a four port flask. Weigh an appropriate amount of catalyst and add it to the flask at constant temperature. The process is simple, the reaction is stable, easy to control, the reaction conditions are mild, and the glucose conversion is about 95%.