Allantoin Powder CAS 97-59-6

Allantoin Powder is uncovered in vesicular liquid, fetal urine and some plants. Nevertheless doing away with sores from these substances is also expensive. The existing techniques for generating allantoin consist of: potassium permanganate oxidation of urea acid technique: home heating dichloroacetic acid and urea to manufacture allantoin; right condensation approach of glyoxylic acid and urea. 1. The treatment using dichloroacetic acid and urea as basic materials is as comply with: Put salt methoxide choice and methanol right into the reaction tank, relaxing to 40-50 ° C, gradually add dichloroacetic acid dropwise, and afterwards reflux for 2 hours after the addition. Terrific to location temperature, filter, neat with methanol, integrate the filtrate and add salt dimethoxylate methanol choice. The option was reduced to entirely dry skin under lowered pressure, included 2.8 parts of hydrochloric acid, warmed up on a water restroom and mixed right into a paste. After that raise the temperature to 90 ° C, after that awesome to around 10 ° C, filter, consist of 0.25 parts of hydrochloric acid and urea to the little liquid, warm to liquify, and react at 80 ° C for 2 hours. Outstanding and materialize, later on maintain it at 0 ° C for higher than 3 hours, centrifuge, clean with water, rotate dry, and dry to get a great thing. The crude thing is recrystallized with 15 times of water to get allantoin. The total return of dichloroacetic acid is 30.3%. 2. Straight condensation of glyoxylic acid and urea (glyoxylic acid is managed oxidation of glyoxal) Procedure circumstances: (1) Oxidation in a 500ml four-neck container gotten ready with mechanical mixing, condenser, thermostat and going down network, Include 193g (1mol) 30% glyoxal liquid treatment, and include 135.5 g (1mol) 45% nitric acid dropwise with mixing while handling the inner temperature level to 40 ± 2 ° C. After the enhancement, continue the stirring feedback at this temperature degree for 2-3 hours up until the red-brown oxidation stops. Retreat, the response treatment adjustments blue-green and vanishes. Adjustment to a basic filtration gadget, simplify out concerning 125g of water at pertaining to 2.76 kPa and the outside temperature level does not surpass 60 ° C. The concentrated remedy is enabled to stand at room temperature level over evening. The precipitated oxalic acid crystals (19g after drying, totaling up to 0.21 mol) have an emphasis of 39%. ). Remain to mix and react at an internal temperature level degree of 40 ± 2 ° C for worrying 8 hours, and the oxidation reaction will most definitely be ended up. (2) Condensation In a 500ml three-necked flask furnished with a mechanical stirrer, condenser and thermostat, include the above 150g glyoxylic acid liquid remedy, then include 170g (2.83 mol) urea and 23.3 g concentrated hydrochloric acid, and warm with mixing up till the internal temperature degree gets to 80 ℃. After around 15 mins, the urea liquifies and the catalyst ends up being a clear liquid. After concerning 30-45 minutes, the catalyst comes to be white and turbid, and later on the white precipitate progressively elevates. Stir for 1 hour at an inner temperature degree of 80 ° C. Quit home heating and cool down the driver to area temperature degree. Make use of a Buchner channel to build up the white precipitate and accelerate with cold water a variety of times to get raw allantoin. Recrystallize with 1000ml pure water. 60-63% of white great crystalline allantoin is obtained, with a melting point of 236 ° C (deterioration). Based upon glyoxal, the allantoin yield is 38-40% of the principle (weight yield is 103-108%).