Method 1. Use dried kelp or dried sargassum as raw material
Soaking and color fixation Take 120kg of dried kelp or 180kg of dried sargassum (generally the glue content is greater than 15%), remove sediment and other substances, add water (or seaweed lotion containing less than 2% mannitol) 2-3t, soak at room temperature For two hours, scrub with water to remove impurities such as mannitol, and recover mannitol from the solution. Wash the clean raw materials, add 1% formaldehyde solution of 15 times the dry weight of the raw materials, soak at room temperature for 16-24 hours, wash the fixed raw materials with water once, and chop them as appropriate.
Dried kelp (or dried sargassum) [water, HCHO]→[16-24h] finely ground kelp
Digestion Take 10-15g/L (1%-1.5%) sodium carbonate solution of 10-15 times the amount according to the dry weight of the raw material, and steam it to 40-45°C (spring, autumn) or 30-40°C (summer) or 50-55°C (winter) (Sargassum 65-70°C), add the color-fixed raw materials, heat and digest for 4 hours, until the materials become paste and reach the end of digestion to obtain a paste-like glue.
Color-fixing kelp [Na2CO3]→[heating and digesting for 4h] pasty glue
Precipitation Dilute the pasty glue solution with water to 60-70 times the dry weight of the raw material, stir evenly, let it settle at room temperature for 16-20 hours, release the supernatant, filter it through 80-100 mesh silk silk, and filter it with a fine cloth bag. A clear sodium alginate solution was obtained. The glue solution extruded from the lower layer of sediment was re-precipitated for 4-8 hours, finely filtered with a fine cloth bag, the residue was discarded, and the clarified filtrate was combined to obtain the glue solution.
Acid coagulation Add 60-70L of hydrochloric acid (or 40-50L of sulfuric acid) into 20000L of clarified glue in a trickle, stir slightly, let it stand for a while, the pH reaches 1-1.5, and the waste acid solution released from the lower part is clear and transparent, reaching the end point. The alginic acid after acid coagulation is washed with water until the pH of the lotion reaches 1.5-2, packed into bags, self-filtered for a while, and squeezed to obtain alginic acid.
Supernatant [HCl]→[pH1-1.5] seaweed liquid
Bleaching and degradation Take 200kg of alginic acid (moisture less than 90%) and mash it, add 80-100kg of ethanol with a volume fraction of 90% and 10-14L of 300g/L (30%) NaOH solution to obtain sodium alginate slurry, neutralization time No more than 8h, control pH7-8. After neutralization, add 24-30L of sodium hypochlorite solution (content 30-50g/L) for bleaching, then use about 5-7L of sodium sulfite solution (content 20-27g/L) to reduce the excess sodium hypochlorite, and control the pH to 8 until starch potassium iodide does not appear. until blue, ethanol was filtered off, and dried to obtain oligomeric sodium alginate.
Alginic acid [ethanol, NaOH] → [8h, pH7-8] sodium alginate slurry [NaClO, Na2SO3] → [pH8] oligomeric sodium alginate
Drying and pulverization Take the wet oligomeric sodium alginate, spread it evenly in a baking tray, dry it at 60-80°C for 2-8 hours, and pulverize it to obtain the finished product of white oligomeric sodium alginate.
Wet oligomeric sodium alginate[60-80℃,2-8h]→Oligomeric sodium alginate finished product
Method two, the preparation method of raw material with sea-tangle (mixed with 1/3 seaweed)
Soak, fix color, digest, precipitate kelp (mixed with 1/3 seaweed), remove sediment and other things, add water to soak for two hours, wash, put 0.8% formaldehyde solution 10 times the dry weight of raw materials to soak and fix color for more than 16 hours ( summer is short, winter is long). Take 10-15 times the amount of 10-15g/L (1%-1.5%) sodium carbonate according to the dry weight of raw materials, raise the temperature to about 80°C, add raw materials, keep warm at 50-60°C, stir and digest at 60r/min for 3-4h , Dilute the digestive solution with water that is 60-70 times the dry weight of the raw material, measure the viscosity of the solution with an Engler viscometer at 110 Pa·s, and settle for 8 hours. Release the supernatant, filter through 80-100 mesh silk, press filter the lower sediment, remove the residue, re-precipitate the filtered glue for 4-8 hours, combine the filtrates to obtain the supernatant.
Kelp (mixed with 1/3 seaweed) [water, HCHO] → [normal temperature 18h] solid color [Na2CO3, water] → [50-60℃, 3-4h] paste [water] → [8h] supernatant
Acid coagulation, neutralization, drying Take the clear glue solution and filter it into the acid polymerization tank, add hydrochloric acid at the same time, the glue tube and the acid tube double tubes touch together, the acid coagulation is rapid, within half an hour, and the pH is controlled at 1-1.5 , the alginic acid after acid coagulation is washed with water, the pH of the lotion is 1.5-2, bagged, self-filtered for a while, and press-filtered to obtain alginic acid with a water content of 85%-90%, then mix the alginic acid into pieces, and add an appropriate amount The sodium alginate slurry is neutralized by soda ash for no more than 8 hours. After the neutralization is uniform, spread it on a glass plate and directly dry it at 70-80°C, and then pulverize it at no more than 90°C to obtain crude sodium alginate.
Supernatant [HCl]→[pH1-1.5] alginic acid [water]→[pH1.5-2] alginic acid [Na2CO3]→[pH7-8, 8h] seaweed sodium slurry→[70-80℃] crude products
Bleaching and degradation Take 280L of soft water and heat it to 60-70°C, stir and sprinkle 10kg of sodium alginate evenly, continue heating and stirring to dissolve completely, then add an appropriate amount of sodium hypochlorite solution evenly, and stir well. During the reaction process, the viscosity of the glue solution gradually decreased, and the color of the reaction solution became lighter. After the viscosity was qualified, 2 kg of activated carbon was added immediately, stirred for 20 minutes, decolorized, and filtered while hot to obtain a clarified filtrate. Crude product [water, Na2CO3, activated carbon] → [60-70 ° C] clarified filtrate (oligomeric sodium alginate) precipitates, and the dried filtrate is passed to a sedimentation tank filled with 80% ethanol. Ethanol: filtrate = 2: 1 (volume ratio ) precipitation, add activated carbon 1kg, decolorize, press filter. Centrifuge the resulting sediment to dry the ethanol, take out the fibrous material and mash it, soak it in 90%-95% ethanol, fully dehydrate, and dry it again, check whether there is any foreign matter on the surface, if there is any foreign matter on the surface, scrape off the surface, and then make granules, 65 ℃ After drying, the finished product of oligomeric sodium alginate is obtained. The relative molecular mass is 20000-31000.
Oligomeric sodium alginate [ethanol] → [below 65°C] oligomeric sodium alginate finished product
The preparation takes 4 g of oligomeric sodium alginate, 50 g of glucose, 3 g of sodium chloride, 0.015 g of citric acid, and 0.113 g of disodium hydrogen phosphate (Na2HPO4·12H2O), add water for injection to 1000 ml.
Take 1/2 of the total amount of water for injection, slowly add sodium alginate under continuous stirring, heat properly until fully dissolved, then add sodium chloride, citric acid and disodium hydrogen phosphate and stir until fully dissolved. In addition, dissolve the glucose in a certain amount of water, mix it with the above solution, and then add water to the full amount. According to the total amount of liquid medicine, add 1-3g/L (0.1%-0.3%) activated carbon, boil for 20-30min, add 4-10 layers of filter paper to filter through a Buchner funnel, and obtain a colorless and clear liquid (relative viscosity is 2.4-3, pH5-7) and then filter with No. 3 vertical melting funnel, sub-package, and sterilize at 110-112°C for 50 minutes under 49kPa (0.5kgf/cm2) pressure to obtain colorless or almost colorless sodium alginate injection.
Oligomeric sodium alginate finished product → oligomeric sodium alginate injection.
