Wool hydrolysis method

Abstract

The invention relates to a wool hydrolysis method, and relates to the technical field of wool hydrolysis, the wool hydrolysis method comprises a wool pretreatment step, an acidic hydrolysis step and an isoelectric precipitation step; the wool pretreatment step comprises the following processes: stirring and mixing cleaned wool, imidazolium ionic liquid and water to obtain a mixture; and adding the mixture into magnetic heating equipment, carrying out magnetic field low-temperature stirring heat treatment, fishing out, washing with water, and draining to obtain the pretreated wool. On the basis of an existing wool hydrolysis process, through the synergistic effect of specific imidazolium ionic liquid and magnetic field low-temperature heat treatment, scale layers of wool can be effectively permeated, wool activation is achieved, favorable conditions are created for the subsequent hydrolysis process, and the hydrolysis process can be carried out in a low-medium-temperature and low-concentration acid solution. The production energy consumption is saved, the side reaction under the high-temperature hydrolysis condition is avoided, and the yield and the purity of the amino acid are improved.

Description

Technical Field

[0001] The invention relates to the technical field of wool hydrolysis, in particular to a wool hydrolysis method. Background Art

[0002] Wool is one of the earliest natural fibers used by humans. Its main chemical component is keratin, which can be used as one of the main raw materials for producing cystine. At present, the traditional method of producing cystine by acid hydrolysis of wool mainly involves washing the wool, removing impurities, and then hydrolyzing it under the catalysis of hydrochloric acid to form a hydrolyzate containing a variety of amino acids, which is neutralized to the isoelectric point of cystine and precipitated to separate the crude cystine. After acid dissolution, activated carbon decolorization, neutralization, filtration, and drying, L-cystine is prepared. However, due to the presence of the scale layer in the wool structure, the acid hydrolysis is severely restricted, resulting in the following deficiencies in the traditional wool acid hydrolysis method:

[0003] 1) It is necessary to use a high concentration of inorganic strong acid such as 8 mol / L or more for hydrolysis. However, the high concentration of inorganic strong acid has strong oxidizing property and produces some side reactions during hydrolysis, so that the hydrolyzate appears black, which affects the accurate regulation of the isoelectric points of various amino acids after hydrolysis, not only reducing the yield of amino acids, but also increasing the difficulty of separation and purification of amino acids, resulting in low purity of the obtained amino acids;

[0004] 2) The hydrolysis needs to be carried out at a high temperature above 100°C. The L-cystine content of the hydrolyzate obtained by hydrolysis below 90°C is extremely low. This process not only increases production energy consumption, but also easily leads to the occurrence of side reactions, further reducing the yield and purity of the obtained amino acids. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method for hydrolyzing wool.

[0006] The present invention provides a method for hydrolyzing wool, which comprises a wool pretreatment step, an acid hydrolysis step and an isoelectric point precipitation step;

[0007] The wool pretreatment step comprises the following processes:

[0008] The cleaned wool, imidazole ionic liquid and water are stirred and mixed to obtain a mixture;

[0009] The mixed material is added into a magnetic heating device for magnetic field low temperature stirring heat treatment, and then taken out for washing and draining to obtain pretreated wool;

[0010] The chemical structural formula of the imidazole ionic liquid is as follows:

[0011] Wherein, R1 is methyl, R2 is C7-C10 straight chain alkyl, and X is halogen.

[0012] Furthermore, the imidazolium ionic liquid includes at least one of 1-heptyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium bromide and 1-decyl-3-methylimidazolium chloride.

[0013] Furthermore, the weight ratio of the cleaned wool, the imidazole ionic liquid and the water is (50-60):(7-13):100.

[0014] Furthermore, the weight ratio of the cleaned wool, the imidazole ionic liquid and the water is 55:11:100.

[0015] Furthermore, the working condition parameters of the magnetic field low-temperature stirring heat treatment include: the flux coil current is 7-12A, the temperature is 45-58°C, the time is 25-35 minutes, and the stirring speed is 80-140rpm.

[0016] Furthermore, the working condition parameters of the magnetic field low-temperature stirring heat treatment include: the flux coil current is 9A, the temperature is 51°C, the time is 30 minutes, and the stirring speed is 100 rpm.

[0017] Further, the acidic hydrolysis step comprises the following process:

[0018] The pretreated wool is sheared, and then added into a hydrochloric acid aqueous solution with a concentration of 3 to 6 mol / L for acid hydrolysis to obtain a hydrolyzate;

[0019] The working condition parameters of the acidic hydrolysis include: a temperature of 60 to 75° C., a time of 7 to 12 hours, and a weight ratio of the pretreated wool to the hydrochloric acid aqueous solution of (0.5 to 1): (1 to 2.2).

[0020] Furthermore, the temperature of the acidic hydrolysis is 68° C., and the concentration of the hydrochloric acid aqueous solution is 5 mol / L.

[0021] Further, the isoelectric point precipitation step includes the following process:

[0022] The pH of the hydrolyzate is adjusted to 5.0 by using ammonia water with a concentration of 5.5-6.5 mol / L, and then the solution is allowed to stand for crystallization and filtered to dry to obtain L-cystine.

[0023] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0024] The embodiment of the present invention provides a method for hydrolyzing wool. Based on the existing wool hydrolysis process, the present invention can effectively penetrate the scale layer of wool by using the synergistic effect of imidazole ionic liquid containing a specific structure and magnetic field low-temperature heat treatment, realize the activation of wool, create favorable conditions for the subsequent hydrolysis process, and enable the hydrolysis process to be carried out at medium and low temperatures and low-concentration acidic solutions. This not only saves production energy consumption, but also avoids the occurrence of side reactions under high-temperature hydrolysis conditions, and improves the yield and purity of amino acids. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0027] In a first aspect, the present invention provides a method for hydrolyzing wool, the method comprising a wool pretreatment step, an acid hydrolysis step and an isoelectric point precipitation step;

[0028] The wool pretreatment step comprises the following processes:

[0029] The cleaned wool, imidazole ionic liquid and water are stirred and mixed to obtain a mixture;

[0030] The mixed material is added into a magnetic heating device for magnetic field low temperature stirring heat treatment, and then taken out for washing and draining to obtain pretreated wool;

[0031] The chemical structural formula of the imidazole ionic liquid is as follows:

[0032] Wherein, R1 is methyl, R2 is C7-C10 straight chain alkyl, and X is halogen.

[0033] The embodiment of the present invention provides a method for hydrolyzing wool. Based on the existing wool hydrolysis process, the present invention can effectively penetrate the scale layer of wool by using the synergistic effect of imidazole ionic liquid containing a specific structure and magnetic field low-temperature heat treatment, realize the activation of wool, create favorable conditions for the subsequent hydrolysis process, and enable the hydrolysis process to be carried out at medium and low temperatures and low-concentration acidic solutions. This not only saves production energy consumption, but also avoids the occurrence of side reactions under high-temperature hydrolysis conditions, and improves the yield and purity of amino acids.

[0034] In some specific embodiments, the imidazolium ionic liquid includes at least one of 1-heptyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium bromide and 1-decyl-3-methylimidazolium chloride.

[0035] In some specific embodiments, the weight ratio of the cleaned wool, the imidazole ionic liquid and the water is (50-60):(7-13):100.

[0036] In some specific embodiments, the weight ratio of the cleaned wool, the imidazole ionic liquid and the water is 55:11:100.

[0037] In some specific embodiments, the working condition parameters of the magnetic field low-temperature stirring heat treatment include: the flux coil current is 7-12A, the temperature is 45-58°C, the time is 25-35 minutes, and the stirring speed is 80-140rpm.

[0038] In some specific embodiments, the working condition parameters of the magnetic field low-temperature stirring heat treatment include: the flux coil current is 9A, the temperature is 51°C, the time is 30 minutes, and the stirring speed is 100 rpm.

[0039] In some specific embodiments, the acidic hydrolysis step comprises the following process:

[0040] The pretreated wool is sheared, and then added into a hydrochloric acid aqueous solution with a concentration of 3 to 6 mol / L for acid hydrolysis to obtain a hydrolyzate;

[0041] The working condition parameters of the acidic hydrolysis include: a temperature of 60 to 75° C., a time of 7 to 12 hours, and a weight ratio of the pretreated wool to the hydrochloric acid aqueous solution of (0.5 to 1): (1 to 2.2).

[0042] In some specific embodiments, the temperature of the acidic hydrolysis is 68° C., and the concentration of the hydrochloric acid aqueous solution is 5 mol / L.

[0043] In some specific embodiments, the isoelectric precipitation step comprises the following process:

[0044] The pH of the hydrolyzate is adjusted to 5.0 by using ammonia water with a concentration of 5.5-6.5 mol / L, and then the solution is allowed to stand for crystallization and filtered to dry to obtain L-cystine.

[0045] It should be noted that the component raw materials involved in the wool hydrolysis method provided in the embodiment of the present invention, unless otherwise specified or specified, can be directly commercially available products or homemade using existing public preparation methods; at the same time, the steps and parameters involved, unless otherwise specified or specified, can be carried out according to the processing technology of the existing hair hydrolysis method or directly using existing equipment, and the present invention document will not describe them one by one.

[0046] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0047] Example 1

[0048] This example provides a method for hydrolyzing wool, which comprises the following steps:

[0049] Wool pretreatment steps:

[0050] The cleaned wool, imidazole ionic liquid (specifically 1-octyl-3-methylimidazolium chloride) and water in a weight ratio of 55:11:100 are stirred and mixed to obtain a mixture;

[0051] The mixed material is added into a magnetic heating device for magnetic field low temperature stirring heat treatment, the flux coil current is 9A, the temperature is 51°C, the time is 30 minutes, the stirring speed is 100rpm, and then the mixed material is taken out, washed and drained to obtain the pretreated wool;

[0052] Acid hydrolysis steps:

[0053] The pretreated wool is sheared, and then added into a hydrochloric acid aqueous solution with a concentration of 5 mol / L for acidic hydrolysis to obtain a hydrolyzate; wherein the working condition parameters of the acidic hydrolysis include: a temperature of 68° C., a time of 9 hours, and a weight ratio of the pretreated wool to the hydrochloric acid aqueous solution of 0.8:1.5;

[0054] Isoelectric precipitation steps:

[0055] The pH of the hydrolyzate is adjusted to 5.0 using 6 mol / L ammonia water, and then the solution is allowed to stand for crystallization and filtered to dry to obtain L-cystine.

[0056] After testing and calculation, the yield of L-cystine obtained in this example was 6.4% and the purity was 99%.

[0057] Example 2

[0058] This example provides a method for hydrolyzing wool, which comprises the following steps:

[0059] Wool pretreatment steps:

[0060] The cleaned wool, imidazole ionic liquid (specifically 1-heptyl-3-methylimidazolium chloride) and water in a weight ratio of 50:7:100 are stirred and mixed to obtain a mixture;

[0061] The mixed material is added into a magnetic heating device for magnetic field low temperature stirring heat treatment, the flux coil current is 7A, the temperature is 58°C, the time is 25 minutes, the stirring speed is 140rpm, and then the mixed material is taken out, washed and drained to obtain pretreated wool;

[0062] Acid hydrolysis steps:

[0063] The pretreated wool is sheared, and then added into a hydrochloric acid aqueous solution with a concentration of 3 mol / L for acidic hydrolysis to obtain a hydrolyzate; wherein the working condition parameters of the acidic hydrolysis include: a temperature of 60° C., a time of 12 hours, and a weight ratio of the pretreated wool to the hydrochloric acid aqueous solution of 0.5:1;

[0064] Isoelectric precipitation steps:

[0065] The pH of the hydrolyzate is adjusted to 5.0 with 6 mol / L ammonia water, and then the solution is allowed to stand for crystallization and filtered to dry to obtain L-cystine.

[0066] After testing and calculation, the yield of L-cystine obtained in this example was 5.2% and the purity was 99%.

[0067] Example 3

[0068] This example provides a method for hydrolyzing wool, which comprises the following steps:

[0069] Wool pretreatment steps:

[0070] The cleaned wool, imidazole ionic liquid (specifically 1-decyl-3-methylimidazolium bromide) and water in a weight ratio of 60:13:100 are stirred and mixed to obtain a mixture;

[0071] The mixed material is added into a magnetic heating device for magnetic field low temperature stirring heat treatment, the flux coil current is 12A, the temperature is 45°C, the time is 35 minutes, the stirring speed is 140rpm, and then the mixed material is taken out, washed and drained to obtain pretreated wool;

[0072] Acid hydrolysis steps:

[0073] The pretreated wool is sheared, and then added into a 6 mol / L hydrochloric acid aqueous solution for acid hydrolysis to obtain a hydrolyzate; wherein the working condition parameters of the acid hydrolysis include: a temperature of 75° C., a time of 7 hours, and a weight ratio of the pretreated wool to the hydrochloric acid aqueous solution of 1:2.2;

[0074] Isoelectric precipitation steps:

[0075] The pH of the hydrolyzate is adjusted to 5.0 with 6 mol / L ammonia water, and then the solution is allowed to stand for crystallization and filtered to dry to obtain L-cystine.

[0076] After testing and calculation, the yield of L-cystine obtained in this example was 5.5% and the purity was 99%.

[0077] Comparative Example 1

[0078] This example provides a method for hydrolyzing wool, which is different from Example 1 only in that the imidazole ionic liquid is 1-butyl-3-methylimidazolium chloride; the remaining steps and parameters are the same.

[0079] After detection and calculation, the yield of L-cystine obtained in this example was 3.8%.

[0080] Comparative Example 2

[0081] This example provides a method for hydrolyzing wool, which differs from Example 1 only in that the magnetic field low-temperature stirring heat treatment is adjusted to a conventional low-temperature stirring heat treatment; the remaining steps and parameters are the same.

[0082] The above-mentioned method for hydrolyzing wool comprises the following steps:

[0083] Wool pretreatment steps:

[0084] The cleaned wool, imidazole ionic liquid (specifically 1-octyl-3-methylimidazolium chloride) and water in a weight ratio of 55:11:100 are stirred and mixed to obtain a mixture;

[0085] The mixed material is added into a heating device for low-temperature stirring heat treatment at a temperature of 51° C. for 30 minutes at a stirring speed of 100 rpm, and then taken out for washing and draining to obtain pretreated wool;

[0086] Acid hydrolysis steps:

[0087] The pretreated wool is sheared, and then added into a hydrochloric acid aqueous solution with a concentration of 5 mol / L for acidic hydrolysis to obtain a hydrolyzate; wherein the working condition parameters of the acidic hydrolysis include: a temperature of 68° C., a time of 9 hours, and a weight ratio of the pretreated wool to the hydrochloric acid aqueous solution of 0.8:1.5;

[0088] Isoelectric precipitation steps:

[0089] The pH of the hydrolyzate is adjusted to 5.0 with 6 mol / L ammonia water, and then the solution is allowed to stand for crystallization and filtered to dry to obtain L-cystine.

[0090] After detection and calculation, the yield of L-cystine obtained in this example was 3.1%.

[0091] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0092] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for hydrolyzing wool, characterized in that: The wool hydrolysis method comprises a wool pretreatment step, an acid hydrolysis step and an isoelectric point precipitation step; The wool pretreatment step comprises the following processes: The cleaned wool, imidazole ionic liquid and water are stirred and mixed to obtain a mixture; The mixed material is added into a magnetic heating device for magnetic field low temperature stirring heat treatment, and then taken out for washing and draining to obtain pretreated wool; The chemical structural formula of the imidazole ionic liquid is as follows: Wherein, R1 is methyl, R2 is C7-C10 straight chain alkyl, and X is halogen.

2. The method for hydrolyzing wool according to claim 1, characterized in that: The imidazolium ionic liquid includes at least one of 1-heptyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium bromide and 1-decyl-3-methylimidazolium chloride.

3. The method for hydrolyzing wool according to claim 1, characterized in that: The weight ratio of the cleaned wool, the imidazole ionic liquid and the water is (50-60):(7-13):

100.

4. The method for hydrolyzing wool according to claim 1, characterized in that: The weight ratio of the cleaned wool, the imidazole ionic liquid and the water is 55:11:

100.

5. The method for hydrolyzing wool according to claim 1, characterized in that: The working condition parameters of the magnetic field low-temperature stirring heat treatment include: the flux coil current is 7-12A, the temperature is 45-58°C, the time is 25-35 minutes, and the stirring speed is 80-140rpm.

6. The method for hydrolyzing wool according to claim 1, characterized in that: The working condition parameters of the magnetic field low-temperature stirring heat treatment include: the flux coil current is 9A, the temperature is 51°C, the time is 30 minutes, and the stirring speed is 100 rpm.

7. The method for hydrolyzing wool according to any one of claims 1 to 6, characterized in that: The acidic hydrolysis step comprises the following process: The pretreated wool is sheared, and then added into a hydrochloric acid aqueous solution with a concentration of 3 to 6 mol / L for acid hydrolysis to obtain a hydrolyzate; The working condition parameters of the acidic hydrolysis include: a temperature of 60 to 75° C., a time of 7 to 12 hours, and a weight ratio of the pretreated wool to the hydrochloric acid aqueous solution of (0.5 to 1): (1 to 2.2).

8. The method for hydrolyzing wool according to claim 7, characterized in that: The temperature of the acidic hydrolysis is 68° C., and the concentration of the hydrochloric acid aqueous solution is 5 mol / L.

9. The method for hydrolyzing wool according to claim 7, characterized in that: The isoelectric precipitation step comprises the following process: The pH of the hydrolyzate is adjusted to 5.0 by using ammonia water with a concentration of 5.5-6.5 mol / L, and then the solution is allowed to stand for crystallization and filtered and dried to obtain L-cystine.

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