CN114315792B - Method for enriching thiaindene from mixture of thiaindene and naphthalene by solvent crystallization coupling extraction rectification method - Google Patents
Method for enriching thiaindene from mixture of thiaindene and naphthalene by solvent crystallization coupling extraction rectification method Download PDFInfo
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Abstract
The invention provides a solvent crystallization coupling extraction rectification method for enriching thiamine from a mixture containing thiamine and naphthalene, which comprises the following steps. a) Dissolving: dissolving a mixture containing thiaindene and naphthalene in a certain amount of extraction solvent to form a solution at 60-100 ℃; b) And (3) crystallization: cooling the solution in the step a) to room temperature to crystallize naphthalene and other impurities from the solution in the step a); c) And (3) filtering: filtering and separating crystals crystallized from naphthalene and other impurities in the step b) to obtain crystallization mother liquor; d) And (3) extracting and rectifying the crystallization mother liquor, and carrying out extraction and rectification under normal pressure or reduced pressure, wherein the theoretical plate number is 10-50, and the reflux ratio is 1-5, so as to obtain the thiamine enriched fraction. The method adopts the solvent crystallization coupling extraction rectification process to enrich the thiamine from the mixture containing the thiamine and naphthalene, and is suitable for enriching the thiamine from the downstream products of coal tar.
Description
Technical Field
The invention relates to a method for enriching thiamine, in particular to a method for enriching thiamine from a mixture containing thiamine and naphthalene, and in particular relates to a method for enriching thiamine from a coal tar downstream product.
Background
Thiabendazole is also called benzothiophene, is an important fine chemical raw material and is widely used in the fields of medicines, pesticides, optical materials, dyes and the like. The mass fraction of thiaindene in the coal tar is about 0.4%, thiaindene resources in the tar are mainly concentrated in naphthalene fraction after tar distillation, about 10% of thiaindene in naphthalene crystallization residual oil is not fully utilized at present.
The boiling point of the thiamphenicol is similar to that of naphthalene, and the thiamphenicol is difficult to separate by adopting a common rectification method. According to the characteristic that thiaindene and naphthalene have different solubilities in a solvent, separation can be carried out by a solvent crystallization method, and the existing process for preparing refined naphthalene by solvent crystallization is adopted. For example, chinese patent application publication No. CN1038087A, publication No. 12/20 of 1989, discloses a process for producing refined naphthalene from crude naphthalene, which comprises recrystallizing crude naphthalene with alcohol as solvent. The invention discloses a process for preparing refined naphthalene by solvent crystallization, which uses methanol, ethanol and acetone as solvents to crystallize and refine crude naphthalene, wherein the publication number of the Chinese patent application is CN1040576A, and the publication date is 21 of 3 of 1990. Chinese patent application publication No. CN1057252a, publication No. 12/25 1991, discloses a process for producing refined naphthalene, which comprises crystallizing and refining crude naphthalene with ethanol mixed solvent. The separation of thiaindene from naphthalene by a solvent crystallization method is mainly used for refining naphthalene at present, and monohydric alcohol is commonly used as a crystallization solvent.
The Chinese patent CN200810204062.9 discloses a method for enriching thiamine from a mixture containing thiamine and naphthalene, which adopts dihydric alcohol as a crystallization solvent, and remarkably improves the enrichment degree of the thiamine.
Experimental results show that when the ratio of the thiamine content to the naphthalene content in the material is close to 1:1, the ratio of the thiamine content to the naphthalene content of the solvent crystal is still close to 1:1, so that the solvent crystal method is difficult to separate and refine. Other methods are needed to break the balance point of the thiaindene content and the naphthalene content of 1:1, and further improve the enrichment degree of the thiaindene.
By adopting the extractive distillation technology, adding a certain high boiling point solvent to the distillation system tends to significantly increase the relative volatilities between the components so that separation becomes easy. Xu Zhizhen et al, university of North China, 1999, 29 (1): 29. JP62-149633, 1987, uses extractive distillation to refine naphthalene.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to provide a method for enriching thiamine from a mixture containing thiamine and naphthalene by solvent crystallization coupling extraction rectification so as to improve the enrichment degree of the thiamine.
The technical scheme of the invention is that the method for enriching thiamine from the mixture of thiamine and naphthalene by using a solvent crystallization coupling extraction rectification method comprises the following steps:
a) Dissolving: dissolving a mixture containing thiamine and naphthalene in an extraction solvent, wherein the mass ratio of the mixture containing thiamine and naphthalene to the extraction solvent is 1:0.5 to 1:4, forming a solution at 60-100 ℃;
b) And (3) crystallization: cooling the solution in the step a) to room temperature to crystallize naphthalene and other impurities from the solution in the step a);
c) And (3) filtering: filtering and separating crystals crystallized from naphthalene and other impurities in the step b) to obtain crystallization mother liquor;
d) And (3) extracting and rectifying: and (3) extracting and rectifying the crystallization mother liquor, and carrying out extraction and rectification under normal pressure or reduced pressure, wherein the theoretical plate number is 10-50, and the reflux ratio is 1-5, so as to obtain the thiamine enriched fraction.
The above-mentioned mother liquor for crystallization refers to a liquid obtained after filtration and separation. The main component of the crystal obtained by crystallization is naphthalene.
The mass ratio of the mixture containing thiamine and naphthalene to the extractive distillation solvent may depend on the thiamine content in the mixture containing thiamine and naphthalene. For raw materials with higher thiaindene content, the solvent consumption is more, so that the yield of the thiaindene is improved; for raw materials with low thiaindene content, the solvent consumption is less, so that the enrichment degree of the thiaindene is improved.
According to the method for enriching thiaindene from the mixture of thiaindene and naphthalene by the solvent crystallization coupling extraction and rectification method, preferably, the mixture containing thiaindene and naphthalene in the step a) is refined naphthalene crystallization residual oil or naphthalene fraction after coal tar distillation. I.e. industrial naphthalene.
The process for the enrichment of thiaindene from mixtures of thiaindene and naphthalene according to the invention by solvent crystallization coupled extractive distillation is preferably characterized in that the extraction solvent in step a) is a compound having a boiling point higher than that of thiaindene and which is capable of generating a strong interaction with thiaindene molecules.
Further, the extraction solvent in the step a) is one or more selected from triethylene glycol, tetraethylene glycol and N-Methyldiethanolamine (MDEA). The extraction solvent is characterized by a compound with a boiling point higher than that of thiaindene and capable of generating stronger interaction with thiaindene molecules. Triethylene glycol is a triol and tetraethylene glycol is tetraethylene glycol.
Preferably, in step a), the mass ratio of the mixture containing thiaindene and naphthalene to the extraction solvent is 1:0.5-1:3.
further, in step a), the mass ratio of the mixture containing thiaindene and naphthalene to the extraction solvent is 1:0.5-1:2.
the beneficial effects of the invention are as follows:
the existing solvent crystallization method and extraction and rectification method are mainly used for refining naphthalene to separate thiaindene from naphthalene, and the aim is to improve the purity of the crystallized product naphthalene. Chinese patent No. CN200810204062.9 proposes a method for enriching thiamine from a mixture containing thiamine and naphthalene, using a glycol as a solvent, performing solvent crystallization on the thiamine mixture, and then distilling to remove the glycol solvent to obtain the enriched thiamine.
Unlike the enrichment method of thiamine in the mixture proposed by Chinese patent No. CN200810204062.9, the present invention provides a solvent crystallization coupling extraction rectification method for enriching thiamine from the mixture containing thiamine and naphthalene, wherein the enrichment degree of thiamine is obviously improved by further enriching thiamine through extraction rectification in addition to the enrichment of thiamine through solvent crystallization.
In addition, when the ratio of the thiamine content to the naphthalene content in the material is close to 1:1, the thiamine and the naphthalene are difficult to separate by a solvent crystallization method, so that the enrichment degree of the thiamine is further improved. The invention provides a solvent crystallization coupling extraction rectification process, which can break the balance point of the thiaindene content and the naphthalene content of 1:1 and further improve the enrichment degree of the thiaindene.
Detailed Description
For a better understanding of the present invention, the following examples are further illustrated, but are not limited to the following examples. For the purposes of illustrating the present invention, the thiaindene naphthalene ratio and thiaindene concentrate ratio are defined herein as follows:
thiaindene naphthalratio = thiaindene content in mixture/naphthalene content in mixture
Thiaindene concentration ratio = thiaindene naphthalene ratio of product/thiaindene naphthalene ratio of starting material
Embodiment one:
500g of a refined naphthalene crystallization residue having a thiaindene-containing content of 9.20% and a naphthalene content of 74.36% and a thiaindene-naphthalene ratio of 0.124 was dissolved in 500g of triethylene glycol at 80℃and stirred to form a solution. The solution is then cooled naturally to room temperature to crystallize naphthalene and other impurities. The solution was then filtered to separate out crystals, and the filtrate obtained was a mother liquor of crystallization. The thiaindene content was 7.98%, the naphthalene content was 25.92% and the thiaindene naphthalene ratio was 0.308 by gas chromatography. The thiamine concentration ratio was 2.484 and the thiamine recovery rate was 63.49%. Obviously, the thiamphenicol is effectively separated and enriched relative to naphthalene.
Embodiment two:
3000g of a triethylene glycol mixed solution containing 7.98% of thiaindene and 25.92% of naphthalene with a thiaindene naphthalene ratio of 0.308 is subjected to extractive distillation. The volume of the rectifying still is 5000 ml, the inner diameter of the rectifying column is 40 mm, the effective height of the column is 1600 mm, the column is filled with structured packing, the theoretical plate number is about 25, and the values of the pressure at the top of the column and the pressure at the bottom of the column can be displayed. Under the condition of reflux ratio of 4 and tower pressure of 35-60KPa, the thiaindene and naphthalene are extracted, rectified and separated, and the experimental results are shown in table 1.
TABLE 1 extractive distillation experiment results with triethylene glycol as extractant
| Fraction number | Bottom temperature of tower | Distillation yield (g) | Naphthalene content, percent | Thiaindene content, percent | Thiaindene naphthalene ratio | Concentration ratio |
| 1 | 224 | 88.0 | 14.60 | 1.51 | 0.103 | 0.334 |
| 2 | 224 | 87.0 | 65.25 | 11.13 | 0.171 | 0.555 |
| 3 | 228 | 95.0 | 67.58 | 13.16 | 0.195 | 0.633 |
| 4 | 231 | 85.0 | 68.34 | 12.95 | 0.189 | 0.614 |
| 5 | 235 | 99.0 | 68.97 | 13.28 | 0.193 | 0.627 |
| 6 | 238 | 109.0 | 69.98 | 16.10 | 0.230 | 0.747 |
| 7 | 241 | 98.0 | 66.72 | 19.65 | 0.295 | 0.958 |
| 8 | 241 | 92.0 | 60.87 | 23.70 | 0.389 | 1.263 |
| 9 | 243 | 50.0 | 49.86 | 28.52 | 0.572 | 1.857 |
As can be seen from the experimental results in Table 1, the fraction above 241℃was cut to obtain a thiaindene-and-naphthalene further thiaindene-enriched fraction. Because the content of thiaindene in the raw materials is low, no fraction with the content of thiaindene being more than that of naphthalene is obtained after extraction and rectification.
Embodiment III:
3000g of a triethylene glycol mixed solution with 11.56% of thiaindene and 23.27% of naphthalene are subjected to extractive distillation, wherein the thiaindene-naphthalene ratio is 0.497. The thiaindene is extracted, rectified and separated under the conditions of about 25 theoretical plates, reflux ratio of 4 and tower pressure of 41-60KPa, and the experimental results are shown in Table 2.
TABLE 2 extractive distillation experiment results with triethylene glycol as extractant
| Fraction number | Bottom temperature of tower | Distillation yield (g) | Naphthalene content, percent | Thiaindene content, percent | Thiaindene naphthalene ratio | Concentration ratio |
| 1 | 210 | 107 | 51.35 | 10.85 | 0.211 | 0.425 |
| 2 | 213 | 80 | 58.52 | 19.57 | 0.334 | 0.672 |
| 3 | 217 | 82 | 57.74 | 20.41 | 0.353 | 0.710 |
| 4 | 223 | 95 | 58.59 | 21.88 | 0.373 | 0.751 |
| 5 | 228 | 117 | 57.83 | 23.27 | 0.402 | 0.809 |
| 6 | 234 | 91 | 57.58 | 24.92 | 0.433 | 0.871 |
| 7 | 240 | 92 | 57.14 | 26.71 | 0.465 | 0.936 |
| 8 | 245 | 85 | 57.45 | 27.27 | 0.475 | 0.956 |
| 9 | 248 | 81 | 56.65 | 27.19 | 0.480 | 0.966 |
| 10 | 253 | 53 | 28.47 | 36.30 | 1.275 | 2.565 |
| 11 | 257 | 80 | 26.96 | 36.00 | 1.335 | 2.687 |
| 12 | 259 | 60 | 25.51 | 44.10 | 1.729 | 3.479 |
As can be seen from the experimental results in Table 2, a fraction above 253℃was taken to obtain a thiaindene fraction enriched in thiaindene and naphthalene further, and the thiaindene content in this thiaindene fraction was greater than that in naphthalene, which was not obtained by enriching thiaindene by crystallization from a solvent.
Embodiment four:
3000g of a triethylene glycol mixed solution with the thiaindene content of 19.27% and the naphthalene content of 27.07% and the thiaindene naphthalene ratio of 0.712 are subjected to extractive distillation. The thiaindene is extracted, rectified and separated under the conditions of theoretical plate number of about 25, reflux ratio of 4 and tower pressure of 39-49KPa, and the experimental results are shown in Table 3.
TABLE 3 extractive distillation experiment results with triethylene glycol as extractant
| Fraction number | Bottom temperature of tower | Distillation yield (g) | Naphthalene content, percent | Thiaindene content, percent | Thiaindene naphthalene ratio | Concentration ratio |
| 1 | 203 | 110.7 | 33.29 | 13.80 | 0.415 | 0.583 |
| 2 | 207 | 111.9 | 39.00 | 19.70 | 0.505 | 0.709 |
| 3 | 216 | 90.5 | 40.53 | 22.64 | 0.559 | 0.785 |
| 4 | 221 | 109.4 | 42.18 | 25.41 | 0.602 | 0.846 |
| 5 | 223 | 102.2 | 42.57 | 25.82 | 0.607 | 0.853 |
| 6 | 224 | 120.1 | 45.58 | 18.87 | 0.414 | 0.581 |
| 7 | 224 | 56.4 | 45.43 | 21.06 | 0.464 | 0.652 |
| 8 | 224 | 129.2 | 40.99 | 24.26 | 0.592 | 0.831 |
| 9 | 226 | 104.2 | 41.11 | 33.86 | 0.824 | 1.157 |
| 10 | 232 | 107.1 | 40.61 | 37.27 | 0.918 | 1.289 |
| 11 | 234 | 109.6 | 36.01 | 40.43 | 1.123 | 1.577 |
| 12 | 236 | 92.4 | 26.55 | 46.10 | 1.736 | 2.438 |
| 13 | 238 | 90.0 | 11.30 | 29.95 | 2.650 | 3.722 |
From the experimental results in Table 3, it can be seen that the fraction above 226 ℃ is intercepted, and a thiaindene fraction further enriched in thiaindene can be obtained; the fraction with the thiaindene content being more than naphthalene content can be obtained by intercepting the fraction with the temperature of more than 234 ℃, and the fraction with the thiaindene content being more than naphthalene content can not be obtained by only enriching the thiaindene by solvent crystallization.
Fifth embodiment:
3000g of tetraethylene glycol mixed solution with 6.33% thiaindene content and 49.57% naphthalene content and thiaindene naphthalene ratio of 0.128 are subjected to extractive distillation. The thiaindene is extracted, rectified and separated under the conditions of about 25 theoretical plates, reflux ratio of 4 and tower pressure of 24-29KPa, and the experimental results are shown in Table 4.
TABLE 4 extractive distillation experiment results with tetraethyleneglycol as extractant
From the experimental results in Table 4, it can be seen that the fraction above 221 ℃ is intercepted to obtain the thiamine fraction further enriched in thiamine; as the used extractive distillation raw material thiaindene naphthalene is lower, the obtained thiaindene-enriched fraction has lower thiaindene content.
Example six:
3000g of a mixed solution of thiaindene with a content of 5.87% and a content of naphthalene with a content of 27.24% and an N-methylglycol amine (MDEA) with a thiaindene naphthalene ratio of 0.215 was subjected to extractive distillation. The thiaindene is extracted, rectified and separated under the conditions of about 25 theoretical plates, reflux ratio of 4 and tower pressure of 32-40KPa, and the experimental results are shown in Table 5.
Table 5N-methylglycol amine (MDEA) as extractant
| Fraction number | Bottom temperature of tower | Distillation yield (g) | Naphthalene content, percent | Thiaindene content, percent | Thiaindene naphthalene ratio | Concentration ratio |
| 1 | 202 | 64.9 | 45.27 | 5.59 | 0.123 | 0.572 |
| 2 | 203 | 75.5 | 63.03 | 8.54 | 0.135 | 0.628 |
| 3 | 203 | 65.0 | 70.29 | 10.45 | 0.149 | 0.693 |
| 4 | 205 | 71.1 | 73.04 | 12.10 | 0.166 | 0.772 |
| 5 | 207 | 55.4 | 71.99 | 12.93 | 0.180 | 0.837 |
| 6 | 206 | 77.0 | 72.41 | 14.41 | 0.199 | 0.926 |
| 7 | 208 | 79.5 | 70.24 | 16.92 | 0.241 | 1.121 |
From the experimental results in Table 5, it can be seen that the fraction above 208℃is cut off to obtain a thiaindene fraction which is further enriched in thiaindene; as the used extractive distillation raw material thiaindene naphthalene is lower, the obtained thiaindene-enriched fraction has lower thiaindene content.
The invention provides a method for enriching thiamine from a mixture containing thiamine and naphthalene. The method adopts the solvent crystallization coupling extraction rectification process to enrich the thiamine from the mixture containing the thiamine and naphthalene, and is suitable for enriching the thiamine from the downstream products of coal tar.
Claims (4)
1. A method for enriching thiamine from a mixture of thiamine and naphthalene by a solvent crystallization coupling extraction rectification method is characterized by comprising the following steps of: which comprises the following steps:
a) Dissolving: dissolving a mixture containing thiamine and naphthalene in an extraction solvent, wherein the mass ratio of the mixture containing thiamine and naphthalene to the extraction solvent is 1:0.5-1: 4, forming a solution at 60-100 ℃; the extraction solvent is selected from one or more of triethylene glycol, tetraethylene glycol and N-Methyldiethanolamine (MDEA);
b) And (3) crystallization: cooling the solution in the step a) to room temperature to crystallize naphthalene and other impurities from the solution in the step a);
c) And (3) filtering: filtering and separating crystals crystallized from naphthalene and other impurities in the step b) to obtain crystallization mother liquor;
d) And (3) extracting and rectifying: and (3) extracting and rectifying the crystallization mother liquor, and carrying out extraction and rectification under normal pressure or reduced pressure, wherein the theoretical plate number is 10-50, and the reflux ratio is 1-5, so as to obtain the thiamine enriched fraction.
2. The method for enriching thiamine from the mixture of thiamine and naphthalene by the solvent crystallization coupling extraction rectification method according to claim 1, wherein the method comprises the following steps of: the mixture containing thiaindene and naphthalene in the step a) is refined naphthalene crystallization residual oil or naphthalene fraction after coal tar distillation.
3. The method for enriching thiamine from the mixture of thiamine and naphthalene by the solvent crystallization coupling extraction rectification method according to claim 1, wherein the method comprises the following steps of: in step a), the mass ratio of the thiaindene-and naphthalene-containing mixture to the extraction solvent is 1:0.5-1:3.
4. the method for enriching thiamine from the mixture of thiamine and naphthalene by the solvent crystallization coupling extraction rectification method according to claim 1, wherein the method comprises the following steps of: in step a), the mass ratio of the thiaindene-and naphthalene-containing mixture to the extraction solvent is 1:0.5-1:2.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1038087A (en) * | 1988-10-12 | 1989-12-20 | 吉林化工学院 | The production method of refined naphthalene |
| CN1040576A (en) * | 1989-09-19 | 1990-03-21 | 马红龙 | Technology for production of refined naphthalene by crystalization in solvents |
| CN1057252A (en) * | 1991-07-12 | 1991-12-25 | 唐山市焦化厂 | A kind of production method of refined naphthalene |
| CN101747317A (en) * | 2008-12-04 | 2010-06-23 | 上海宝钢化工有限公司 | Method for enriching thianaphthene from mixture containing thianaphthene and naphthalene |
| CN109627139A (en) * | 2017-10-09 | 2019-04-16 | 中国石化扬子石油化工有限公司 | Indane separation method in a kind of cracking carbon nine |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1038087A (en) * | 1988-10-12 | 1989-12-20 | 吉林化工学院 | The production method of refined naphthalene |
| CN1040576A (en) * | 1989-09-19 | 1990-03-21 | 马红龙 | Technology for production of refined naphthalene by crystalization in solvents |
| CN1057252A (en) * | 1991-07-12 | 1991-12-25 | 唐山市焦化厂 | A kind of production method of refined naphthalene |
| CN101747317A (en) * | 2008-12-04 | 2010-06-23 | 上海宝钢化工有限公司 | Method for enriching thianaphthene from mixture containing thianaphthene and naphthalene |
| CN109627139A (en) * | 2017-10-09 | 2019-04-16 | 中国石化扬子石油化工有限公司 | Indane separation method in a kind of cracking carbon nine |
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