Method for extracting caffeine by low temperature crystallization

[0029] (1) Soak the tea leaves in pure water, the weight ratio of the tea water is 1:7, the temperature of the pure water is 85°C, and the soaking time is 40 minutes to obtain the leaching solution;

[0030] (2) Repeat step (1) 3 times;

[0031] (3) Extract the leachate with chloroform, the weight ratio of chloroform to the leachate is 1:5, to obtain the extract;

[0032] (4) obtain caffeine crude product after carrying out chloroform recovery to extract;

[0033] (5) dissolving the caffeine crude product and water at a weight ratio of 1:8 at 80-100°C, and filtering the solution to obtain a filtrate;

[0034] (6) Activated carbon is put into the filtrate to decolorize, the temperature is maintained at 60-80° C., and the time is 40 minutes to obtain a decolorization solution;

[0035] (7) the decolorizing solution is filtered to obtain the filtrate;

[0036] (8) The filtrate undergoes natural crystallization at a temperature of 10-20° C. to obtain high-purity caffeine.

[0037

[0039] (1) Soak the tea leaves in pure water, the weight ratio of the tea water is 1:10, the temperature of the pure water is 90°C, and the soaking time is 50 minutes to obtain the extract;

[0040] (2) Repeat step (1) 3 times;

[0041] (3) Extract the leachate with chloroform, the weight ratio of chloroform to the leachate is 1:5, to obtain the extract;

[0042] (4) obtain caffeine crude product after carrying out chloroform recovery to extract;

[0043] (5) Dissolving the caffeine crude product and water at a weight ratio of 1:8 at 80-100°C, and filtering the solution to obtain a filtrate;

[0044] (6) Activated carbon is put into the filtrate for decolorization, the temperature is kept at 60-80°C for 45 minutes to obtain a decolorization solution;

[0045] (7) the decolorizing solution is filtered to obtain the filtrate;

[0046] (8) The filtrate undergoes natural crystallization at a temperature of 10-20° C. to obtain high-purity caffeine.

[0047] In this embodiment, the

[0049] (1) Soak the tea leaves in pure water, the weight ratio of the tea water is 1:9, the temperature of the pure water is 95°C, and the soaking time is 50 minutes to obtain the leaching solution;

[0050] (2) Repeat step (1) 4 times;

[0051] (3) Extract the leachate with chloroform, the weight ratio of chloroform to the leachate is 1:5, to obtain the extract;

[0052] (4) obtain caffeine crude product after carrying out chloroform recovery to extract;

[0053] (5) Dissolve the caffeine crude product and water at a weight ratio of 1:8 at 80-100°C, and filter the solution to obtain the filtrate; extract the filtrate with chloroform, and the weight ratio of chloroform to the leachate is 1:5 , to obtain the extract, recover the extract with chloroform to obtain the crude caffeine again, then dissolve the crude caffeine and water again at a ratio of 1:8 by weight at 80-100°C, and filter the solution to obtain the filtrate again ;

[0054] (6) Activated carbon is put into the fi