CN1045603C - Process for extracting caffeine from waste tea dust - Google Patents
Process for extracting caffeine from waste tea dust Download PDFInfo
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- CN1045603C CN1045603C CN97113394A CN97113394A CN1045603C CN 1045603 C CN1045603 C CN 1045603C CN 97113394 A CN97113394 A CN 97113394A CN 97113394 A CN97113394 A CN 97113394A CN 1045603 C CN1045603 C CN 1045603C
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- tea dust
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Abstract
The present invention provides a technology for extracting caffeine from waste tea dust, which can avoid damage of caffeine caused by alkaline lime water with a high caffeine yield. The present invention is characterized in that the caffeine (crude product) is prepared by two-stage leaching and crystallization. In the first stage of the leaching, water is used as solvent for overflowing leaching by boiling. In the second stage of the leaching, ethanol whose concentration is from 70 to 80% is used as solvent for ethanol leaching. Finally, the leaching liquid is concentrated and crystallized to obtain caffeine crude products, and then the caffeine crude products are refined into caffeine.
Description
The present invention relates to tealeaves is the method that raw material extracts natural caffeine, particularly a kind of technology of extracting caffeine from useless tea dust.
Caffeine is called trimethyl-xanthine again, can be used for treating illness such as neurasthenia and spiritual holddown; It is the important source material of all kinds of antipyretic-antalgic medicines of preparation; Also often make the bitters of food and drink.Caffeine is the acicular crystals that white has mercerising, belong to oblique system, the odorless bitter, being placed on for a long time has weathering in the air, lose crystal water when being heated to 100 ℃, the distillation phenomenon is arranged, significantly distil when being heated to 120 ℃, the fusing point of Caffein anhydrous is 235～238 ℃, it is the weakly alkaline material, be soluble in hot water, chloroform, the benzene equal solvent, be slightly soluble in cold water, cold ethanol and acetone etc., be insoluble in ether.
It is synthetic obtaining caffeine approach one, the 2nd, from the natural products such as tealeaves that contain caffeine, extract.Natural caffeine mainly is with the byproduct in the coffee production course of processing or can extracts in machinable byproduct in China and foreign countries.China's tea yield is higher, and tea processing factory is distributed more widely, and just adopting tealeaves since the fifties is that raw material extracts natural caffeine.Learn that from relevant document content of caffeine is higher in the useless tea dust, is about 1～1.2%, useless tea dust in tea making process or low-grade thick tea dust provide the favourable resources of production than horn of plenty for producing caffeine.
Domestic in recent years existing many patent application or reported in literature that from tealeaves, extract caffeine.The technology of getting caffeine from the tealeaves middle age can be divided into two big classes: the one, and subliming method, the 2nd, extraction process, extraction process is divided into CO supercritical extraction and other solvent extraction methods again, the processing method of solvent lixiviate is many, it is more to be that mainly filtrate processing that lixiviate comes out is obtained caffeine crystalline method, and mainly contains following method in leaching stages: 1. ethanol soaks filtration repeatedly; 2. boiling water boiling filtration repeatedly; 3. magnesium oxide aqueous solution boiling filtration repeatedly; 4. the lixiviate of the dilute methanol aqueous solution is filtered.In addition, the comprehensive technological method that extracts tea-polyphenol, chlorophyll, caffeine, catechin from tealeaves has also been studied by units such as Xia Men university, Sichuan Agricultural University, Wuxi Light Industry College.
Solvability according to caffeine, can adopt " lixiviate---crystallization " method, be that the solvent extraction extracts, except containing caffeine, also contain a large amount of tannic acids and other biological alkali such as a spot of chromoprotein matter vegetable jelly and theophylline in the vat liquor of gained.
Useful boiling water boiling filtration adds plumbic acetate, sodium hydroxide impurity elimination crystalline technology in " lixiviate---the crystallization " method that adopts at present, or add sulfuric acid and filter and to add magnesium oxide again and filter, concentrate, then add again saturated calcium hydroxide, technology through periodic crystallisation, also useful ethanol lixiviate filtrate concentrate to add magnesium oxide, evaporate to dryness, adds multiple working procedures such as dilute sulphuric acid concentrates, chloroform extraction and make caffeine through adding water again, and other kinds of processes.
In existing " lixiviate---crystallization " method, the principal element that influences extraction yield is a tannic acid.Tannic acid can form with caffeine and be difficult to the compound that crystallization is separated out, adopt " liming extraction " though a large amount of tannic acids can be removed, but because the alkalescence of liming is very strong, when tea dust being boiled for a long time processing, can make side reactions such as part caffeine generation hydrolysis, decarboxylation, degraded, thereby cause the caffeine extraction yield to descend.
The present invention proposes a kind of technology of extracting caffeine from useless tea dust, and this law can be avoided the destruction of caustic lime water to caffeine, obtains higher caffeine productive rate.
Purpose of the present invention can reach by following measure: this technology is characterised in that: divide two sections lixiviate crystallizations to produce caffeine (crude product), one section lixiviate is to add entry at useless tea dust, adopts water as solvent to carry out the boil water lixiviate; Two sections lixiviates are through concentrated, slag making with the water extract after one section lixiviate, in the slag making material that obtains, add 70～80% ethanol and carry out pure lixiviate as solvent, concentrate vat liquor at last and carry out crystallization and obtain the caffeine crude product, further carry out the refining of caffeine again.
During one section flooding, the clear water of quantitative useless tea dust and 2.5 times of amounts is warming up to boiling in reactor, boiling water boiled about 2～3 hours, and the water extract that obtains is evaporated to paste, add the calcium oxide slag making then, the add-on of calcium oxide is 1/3 of a tea dust amount.
During two sections ethanol lixiviates, add the ethanol lixiviate in the material after slag making, the amount of amount of alcohol added and useless tea dust is 1: 1, should stir in alcohol extracting, the alcohol extracting time should be controlled between 3～5 hours, after alcohol extracting is finished, earlier vat liquor is separated with slag, concentrate then and reclaim ethanol, ethanol content is lower than 1% with its filtration in the solution to be concentrated, and the filtrate crystallization is made caffeine (crude product).
Caffeine crude product refining is that quantitative caffeine crude product that above-mentioned operation is obtained and 10 times water carry out heat of solution, when treating its boiling, adding proper amount of active carbon again decolours, carry out heat filtering immediately after the decolouring, filtrate is left standstill crystallization, after the crystallization, it is carried out centrifugation, cleans crystal, filters after drying and can obtain qualified caffeine purified product, and temperature preferably is controlled between 60～65 ℃ when dry.
The present invention is described further below in conjunction with embodiment and accompanying drawing thereof.
Fig. 1 is the segmentation lixiviate crystallization processes schematic flow sheet that proposes according to the present invention.
Segmentation lixiviate crystallization process, promptly be in leaching process, to divide two stages, one section lixiviate adopts water as solvent to boil lixiviate, the ethanol of two sections lixiviate employings 70% carries out lixiviate as solvent, concentrate vat liquor at last and carry out crystallization and obtain caffeine, the flow process of segmentation lixiviate crystallization process mainly is divided into: flooding (boiling), concentrate, slag making, pure lixiviate, reconcentration and crystallization, seven operations such as refining.
One, the thick water lift lixiviate of caffeine
In the flooding operation, the tea dust that will give up earlier adds in the lixiviate still, adds the clear water of about 2.5 times of amounts while stirring, is warming up to boiling, keeps and can filter in about 2～3 hours, and residue is capable of using as feed; In leaching process,, can replenish an amount of water as one sees fit if vat liquor is less.Stir while concentrating, until being condensed into paste, this moment dope density=1.26～1.30g/ml.
Slag making: the concentrated solution that concentration kettle (I) is sent here adds calcium oxide (CaO) powder while hot, stirs while adding, and until leather hard, the amount of calcium oxide approximately is 1/3 of a tea dust amount.The alcohol lixiviate
After treating that the slag making operation is finished, material changed over to add 70～80% ethanol in the lixiviate jar while hot and carry out alcohol extracting, the amount of alcoholic acid amount and tea dust is suitable.Should suitably stir in the alcohol extracting process, the alcohol extracting time should be controlled between 3～5 hours.
Concentrate (II) and reclaim ethanol: after treating that alcohol extracting is finished, earlier vat liquor is separated with slag, and alcohol extract is sent into concentration kettle (II) carry out concentrating under reduced pressure, concentrate the ethanol that reclaims and to be used further to alcohol extracting, after ethanol content is lower than 1% in the solution to be concentrated, can be with its filtered while hot, and filtrate delivered to crystallizer.
Crystallization (I): the alcohol extracting concentrated solution is statically placed in the crystallizer (I), allow its natural cooling crystallization, after to be crystallized the finishing it is carried out centrifugation, can obtain content and be 90% caffeine crude product, capable of circulation the delivering in the concentration tank (II) of mother liquor of this moment concentrates and utilizes.
Two, caffeine is refining
Decolouring: the caffeine crude product that above-mentioned operation obtains is sent in the dissolving vessel, the water that adds 10 times carries out heat of solution, when treating its boiling, adds an amount of gac again and decolours, carry out heat filtering after the decolouring immediately except that removing slag, the filtrate that obtain this moment is limpid substantially colourless.
Crystallization (II): will decolour and filtrate filtered is delivered in the crystallizer (II) and left standstill crystallization, to be crystallized fully after, it is carried out centrifugation, cleans crystal, filters after drying, can obtain qualified caffeine purified product, temperature preferably is controlled between 60～65 ℃ when dry, in treating process, requiring the filtrate after the decolouring is limpid colourless liquid substantially, during qualitative analysis in the filtrate Ca be (-); In addition, drying temperature can not be too high, in order to avoid caffeine distils and causes damage, has again, wants time of drying suitably, and the overlong time caffeine can weathering lose crystal water.
The raw material consumption of segmentation extracting technology: need by producing 1 kilogram of refining caffeine: 110 kilograms of useless tea dusts (or thick tea dust), 30 kilograms of unslaked limes, 95% industrial spirit is converted to the concentration that is suitable for for 25～30 kilograms.
The consumption of useless tea dust is relevant with its place of production and quality, the useless tea dust in the different places of production, and its extraction yield has difference, and its consumption is difference to some extent also; The caffeine extraction yield (productive rate) that obtains by this technology is about 9 ‰.The caffeine that extracts is smart brilliant, carries out sampling inspection by the requirement and the regulation of Pharmacopoeia of the People's Republic of China nineteen ninety version (two ones), more than its quality is all qualified.
The alcoholic acid consumption is relevant with recovery, reclaims technology controlling and process and must get well, and its consumption can correspondingly reduce.
The present invention is a kind of technology simple products extraction yield height, is convenient to operation, and product matter is better, relatively is fit to township and village enterprises and utilizes useless tea dust to extract the production technique of caffeine.
Claims (4)
1. a technology of extracting caffeine from useless tea dust is characterized in that: divide two sections lixiviate crystallizations to produce caffeine (crude product) to useless tea dust, add water as solvent at useless tea dust during one section lixiviate and carry out the boil water lixiviate; Be the warp of the water extract after one section lixiviate is concentrated, slag making during two sections lixiviates, in the slag making material, add 70～80% ethanol and carry out pure lixiviate, concentrate vat liquor at last and carry out crystallization and obtain the caffeine crude product, further carry out the refining of caffeine again as solvent.
2. technology according to claim 1, it is characterized in that: during one section flooding, the clear water of quantitative useless tea dust and 2.5 times of amounts is warming up to boiling in reactor, boiling water boiled about 2～3 hours, the water extract that obtains is evaporated to paste, add the calcium oxide slag making then, the add-on of calcium oxide is 1/3 of a tea dust amount.
3. technology according to claim 1, it is characterized in that: during two sections ethanol lixiviates, add the ethanol lixiviate in the material after slag making, the amount of amount of alcohol added and useless tea dust is 1: 1, should stir in alcohol extracting, the alcohol extracting time should be controlled between 3～5 hours, after alcohol extracting is finished, earlier vat liquor is separated with slag, concentrate then and reclaim ethanol, ethanol content is lower than 1% with its filtration in the solution to be concentrated, and the filtrate crystallization is made caffeine (crude product).
4. technology according to claim 1, it is characterized in that: caffeine crude product refining is that quantitative caffeine crude product that above-mentioned operation is obtained and 10 times water carry out heat of solution, when treating its boiling, adding proper amount of active carbon again decolours, carry out heat filtering immediately after the decolouring, filtrate is left standstill crystallization, after the crystallization, it is carried out centrifugation, cleans crystal, filters after drying and can obtain qualified caffeine purified product, temperature is controlled between 60～65 ℃ when dry.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97113394A CN1045603C (en) | 1997-08-19 | 1997-08-19 | Process for extracting caffeine from waste tea dust |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97113394A CN1045603C (en) | 1997-08-19 | 1997-08-19 | Process for extracting caffeine from waste tea dust |
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| Publication Number | Publication Date |
|---|---|
| CN1172112A CN1172112A (en) | 1998-02-04 |
| CN1045603C true CN1045603C (en) | 1999-10-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN97113394A Expired - Fee Related CN1045603C (en) | 1997-08-19 | 1997-08-19 | Process for extracting caffeine from waste tea dust |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104496990A (en) * | 2014-10-27 | 2015-04-08 | 芜湖天远科技开发有限责任公司 | Method for extracting caffeine by low temperature crystallization |
| CN113717173B (en) * | 2021-08-31 | 2022-12-09 | 上海赛奥分离技术工程有限公司 | Method for recovering caffeine from caffeine refining mother liquor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1067895A (en) * | 1992-08-06 | 1993-01-13 | 重庆华康生物化工厂 | From tealeaves, extract the production technique of natural caffeine |
| CN1097757A (en) * | 1993-07-23 | 1995-01-25 | 煤炭科学研究总院合肥研究所 | Process for preparing tea natural alkaloid-caffeine |
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1997
- 1997-08-19 CN CN97113394A patent/CN1045603C/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1067895A (en) * | 1992-08-06 | 1993-01-13 | 重庆华康生物化工厂 | From tealeaves, extract the production technique of natural caffeine |
| CN1097757A (en) * | 1993-07-23 | 1995-01-25 | 煤炭科学研究总院合肥研究所 | Process for preparing tea natural alkaloid-caffeine |
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| Publication number | Publication date |
|---|---|
| CN1172112A (en) | 1998-02-04 |
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