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A method for improving the lignin yield of tobacco stems through low-temperature pretreatment of sodium hydroxide/urea/thiourea aqueous solution

A low-temperature pretreatment and sodium hydroxide technology, applied in the field of lignin extraction, can solve the problems of no chemical modification of lignin and low yield, and achieve the effects of small structural change, improved yield and high purity

Active Publication Date: 2018-07-06
CHINA TOBACCO HENAN IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, this treatment method focuses on the degradation of cellulose and the conversion rate of sugar, etc., and does not involve the chemical modification of lignin in the pretreatment process and the low yield.

Method used

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  • A method for improving the lignin yield of tobacco stems through low-temperature pretreatment of sodium hydroxide/urea/thiourea aqueous solution
  • A method for improving the lignin yield of tobacco stems through low-temperature pretreatment of sodium hydroxide/urea/thiourea aqueous solution

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A kind of sodium hydroxide / urea / thiourea aqueous solution low-temperature pretreatment method that improves the lignin yield of tobacco stem, comprises the following steps:

[0025] ①Pre-dry the tobacco stems, crush them, pass through a 40-mesh sieve, and have a moisture content of 6.62% (measured according to the tobacco industry standard YC31-1996 oven method); add 35g of the sieved tobacco stem powder to sodium hydroxide / urea / sulfur In urea / water solution (liquid-solid ratio: 25mL: 1g), stir and react at -8°C for 30min, filter through a 600-mesh filter cloth, wash with water until neutral, and obtain a residue of 12.39g; sodium hydroxide / urea / thiourea / water solution is obtained by the following Component composition in weight percent: sodium hydroxide 8%, urea 8%, thiourea 6.5%, balance is water;

[0026] ②Add the residue obtained in step ① into the acetic acid-sodium acetate buffer solution (solid-to-liquid ratio: 1g:40mL) at pH 4.8, add cellulase, and shake at 50°C...

Embodiment 2

[0035] A kind of sodium hydroxide / urea / thiourea aqueous solution low-temperature pretreatment method that improves the lignin yield of tobacco stem, comprises the following steps:

[0036] ①Dry the tobacco stems in advance, crush them, pass through a 60-mesh sieve, and have a moisture content of 6.53% (measured according to the tobacco industry standard YC31-1996 oven method); add 35g of the sieved tobacco stem powder to sodium hydroxide / urea / sulfur In aqueous urea solution (liquid-solid ratio: 15mL: 1g), stir and react at -10°C for 20min, filter through a 600-mesh filter cloth, wash with water until neutral, and obtain a residue of 12.98g; sodium hydroxide / urea / thiourea / water solution consists of the following weight The composition of the percentage: sodium hydroxide 6%, urea 7%, thiourea 7%, the balance is water;

[0037] ②Add the residue obtained in step ① into the acetic acid-sodium acetate buffer solution with a pH of 6.0 (solid-to-liquid ratio: 1g:20mL), add cellulase, ...

Embodiment 3

[0046] A method for improving the lignin yield of tobacco stems through low-temperature pretreatment of sodium hydroxide / urea / thiourea / water solution, comprising the following steps: ① pre-drying the tobacco stems, pulverizing them, passing through an 80-mesh sieve, and having a moisture content of 6.03% (according to Tobacco industry standard YC31-1996 oven method); add 35g of sieved tobacco stem powder into sodium hydroxide / urea aqueous solution (liquid-solid ratio is 30mL: 1g), stir and react at -9°C for 40min, filter through 600 mesh Cloth filtration, washing to neutrality, obtains 12.75g; Sodium hydroxide / urea / thiourea aqueous solution is made up of the following components in weight percent: sodium hydroxide 7%, urea 6%, thiourea 5%, balance is water;

[0047] ②Add the residue obtained in step ① into the acetic acid-sodium acetate buffer solution with a pH of 4.5 (solid-to-liquid ratio: 1g:45mL), add cellulase, shake and react at a constant temperature at 60°C for 60 hour...

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Abstract

The invention belongs to a method for low-temperature pretreatment of sodium hydroxide / urea / thiourea aqueous solution to improve the lignin yield of tobacco stems. The tobacco stem powder is subjected to low-temperature pretreatment by using sodium hydroxide-urea-thiourea-water mixture, On the one hand, it breaks the connection between cellulose-hemicellulose-lignin in tobacco stem powder, on the other hand, it can dissolve part of cellulose, hemicellulose, water-soluble components, etc., and the residue is subjected to enzymatic hydrolysis-mild acid hydrolysis After treatment, tobacco stem lignin with little structural change and high purity can be obtained at last, and the yield can also be significantly increased, which is beneficial to further research on tobacco lignin.

Description

technical field [0001] The invention belongs to the technical field of lignin extraction, and in particular relates to a method for improving the lignin yield of tobacco stems through low-temperature pretreatment of sodium hydroxide / urea / thiourea aqueous solution. Background technique [0002] With the improvement of smokers' health awareness, reducing harm and coke has become the only way for the future development of the tobacco industry. Among them, lignin is the main aromatic component in tobacco leaves, and is the main source of harmful substances such as polycyclic aromatic hydrocarbons and aromatic amines in tar; pyrolysis will produce catechols and alkyl catechols, causing astringent taste and cancer-promoting activity. In recent years, studying the pyrolysis mechanism of tobacco lignin under the condition of smoking and burning cigarettes is a new idea for reducing tar and harm of cigarettes, which requires the separation of lignin with less structural change from ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08H7/00
CPCC08H6/00
Inventor 楚文娟李文伟李顥程向红冯业双
Owner CHINA TOBACCO HENAN IND