DL-Malic acid CAS 617-48-1

DL-sodium hydrogen malate is a good food additive, which is widely used in aquatic products and meat food because it can increase the freshness of food and give it a good taste. Because it has a certain saltiness, it can be used as a substitute for table salt for food processing and manufacturing, and the amount of table salt can be reduced. In addition, since the content of sodium in DL-sodium hydrogen malate is lower than that of table salt, replacing table salt with DL-sodium hydrogen malate is more suitable for patients with high blood pressure, kidney disease and heart disease.

CN201510001761.3 provides a preparation method of DL-sodium hydrogen malate with simple method and high yield. The technical problem to be solved by this invention adopts the following technical scheme to realize: a kind of preparation method of DL-sodium hydrogen malate is, in the presence of a small amount of anhydrous sodium carbonate, trihydrate DL-disodium malate crystal and DL- The malic acid solids are mixed and ground under solvent-free conditions to form the reaction. The invention utilizes a solvent-free solid grinding reaction method to prepare DL-sodium hydrogen malate, has the characteristics of easy operation, high raw material utilization rate and high product yield, and has no pollution to the environment, conforming to the concept of green chemistry.

In recent years, people have begun to pay attention to cheap biomass materials as biosorbents. For example, biomass materials such as wood chips, rice husks, peanut husks, and corn stalks have been widely used in the treatment of printing and dyeing wastewater. As agricultural waste, flax has large yield, low cost and biodegradability, so it has great development prospects as an adsorbent to treat industrial dye wastewater. CN201610891927.8 provides a preparation method and application of a DL-malic acid modified flax adsorbent.

In order to achieve the above purpose, the technical scheme adopted in the present invention is: a preparation method of a DL-malic acid modified flax adsorbent, comprising the following steps:

S1. After washing the flax with tap water and distilled water, place it in a 70°C oven to dry to constant weight, pulverize it, and pass it through a 180-mesh sieve;

S2. Weigh 10 g of the flax powder obtained in step S1, soak it with 250 mL of sodium hydroxide solution of a certain concentration, and place it on a magnetic heating stirrer for magnetic stirring for 12 h, then filter it with a Buchner funnel and rinse it with deionized water to The pH of the filtrate is close to neutral. After drying the filter residue in an oven at 80°C, it is naturally cooled to room temperature and dried in a drying oven to obtain NaOH modified flax;

S3. Weigh 0.5 g of the obtained NaOH-modified flax into a conical flask, add 200 mL of DL-malic acid with a concentration of 0.8 mol/L, stir at 60° C. for 2 h with a magnetic heating stirrer, and then filter with a Buchner funnel Rinse with deionized water until the pH of the filtrate is close to neutral, dry the filter residue at 80°C, and cool it to room temperature naturally to obtain a flax adsorbent.