Method for producing L-(R) propylidene glycerin
A technology of propylidene glycerol and its production method, which is applied in the direction of organic chemistry, can solve the problems of complicated process, unsuitable for large-scale production, and low production efficiency, and achieve the effect of reducing costs
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Embodiment 1
[0032] Synthesis of L-gulonic acid-1,4-lactone
[0033] Dissolve 23.1 grams of vitamin C in 170 milliliters of water, add 2.2 grams of 5% palladium / carbon catalyst, at 50 ° C and 5.05 × 10 5 Catalyzed hydrogenation under Pa for 24 hours, filtered to remove the catalyst, and evaporated the water under reduced pressure to obtain L-gulonic acid-1,4-lactone, which was recrystallized with a mixed solvent of methanol and ethanol to obtain 22 grams of the product with a yield of 95%. , melting point 182-183.5℃; [α] D 20 is +55.2° (c=1, H 2 O);
[0034] IR(KBr)1770cm -1 ;
[0035] 1 H-NMR (Me 2 SO-d 6 ):
[0036] δ=5.80 (d, 1, OH), 5.30 (d, 1, OH), 4.95 (d, 1, OH) 4.45-4.07 (m, 3), 4.00-3.35 (m, 3), 4.00-3.35 ( m, 3).
[0037] Synthesis of 5,6-O-isopropylidene-L-gulonic acid-1,4-lactone
[0038]Dissolve 221.6 grams of L-gulonic acid-1,4-lactone in 2000 milliliters of N,N-dimethylformamide, cool to 10°C, add 1.8 grams of p-toluenesulfonic acid while stirring, keep the tempe...
Embodiment 2
[0046] Synthesis of L-gulonic acid-1,4-lactone
[0047] Dissolve 200 kg of vitamin C in 1000 liters of water, add 20 kg of 10% palladium / carbon catalyst, at 50 ° C and 5.05 × 10 5 Catalyzed hydrogenation under Pa for 24 hours, filtered to remove the catalyst, and evaporated the water under reduced pressure to obtain a white solid of L-gulonic acid-1,4-lactone, which was recrystallized with a mixed solvent of methanol and ethanol to obtain 196 kg of white cubic crystals , yield 98%, melting point 183-183.5°C, [α] 25 is +55.5° (c=1, H 2 O).
[0048] Synthesis of 5,6-O-isopropylidene-L-gulonic acid-1,4-lactone
[0049] Dissolve 190 kg of L-gulonic acid-1,4-lactone in 1500 liters of N,N-dimethylformamide, cool to 10°C, add 1.8 kg of p-toluenesulfonic acid while stirring, keep the temperature below 10°C and drop Add 150 kg of 2,2-dimethoxypropane, continue stirring at room temperature for 24 hours, then add 220 kg of sodium carbonate decahydrate, filter after 2 hours, and disti...
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