CN103058915A - Method for extracting high-purity 2,4-dimethyl pyridine - Google Patents
Method for extracting high-purity 2,4-dimethyl pyridine Download PDFInfo
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- CN103058915A CN103058915A CN2013100445157A CN201310044515A CN103058915A CN 103058915 A CN103058915 A CN 103058915A CN 2013100445157 A CN2013100445157 A CN 2013100445157A CN 201310044515 A CN201310044515 A CN 201310044515A CN 103058915 A CN103058915 A CN 103058915A
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- lutidine
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Abstract
The invention discloses a method for extracting high-purity 2,4-dimethyl pyridine. The method comprises the following steps of: treating impurities in a 2,4-dimethyl pyridine hydrochloride crystal; adding the washed salt crystal into a methyl benzene solvent which is 0.5-10 times as much as the mass of the crystal; washing 2,4-dimethyl pyridine hydrochloride through the methyl benzene solvent, and repeating twice by other conditions and steps identical to the previous conditions and steps. Obtained 2,4-dimethyl pyridine forms salt once again with concentrated hydrochloric acid, so as to prepare 2,4-dimethyl pyridine with purity greater than 99%, and total yield of forming salt in two times is higher than 85%. Most importantly, content of 2,4-dimethyl pyridine in a crude dimethyl pyridine raw material is changed from 20-70%, and difference with an experimental result is not great, so that industrialization performance is remarkably improved.
Description
Technical field
The present invention relates to the Chemicals production field, be specifically related to a kind of extraction high purity 2, the method for 4-lutidine.
Background technology
As everyone knows, 2,4-lutidine has important use at medicine and dyestuffs industries, also is a kind of common basic chemical industry raw material.The current coal tar distillation that is mainly derived from, it is difficult to obtain by chemosynthesis, but in the coal tar distillation process, the fraction of boiling point between 156～163 ℃ mainly comprises 2,4-lutidine (40%～70%), 2, the mixture of 5-lutidine (10%～35%) and other lutidine because three's boiling point is very approaching, can not further separate with rectificating method again.The separation method of developing thus outside a kind of rectifying is extremely important.
In the prior art, the method for separating 2,4-lutidine mainly contains three kinds: the first, such as the method that US Patent No. 2320322 provides, 2,4-lutidine and 2, the hydrochloride boiling point of 5-lutidine is difference to some extent, Given this, can be isolated by rectifying again.But this method does not have practical significance, because 2,4-dimethyl pyrazole thiamine hydrochloride boiling point is 251 ℃, 2,5-dimethyl pyrazole thiamine hydrochloride boiling point is 245 ℃, and difference of them is very little, and boiling point is very high, and it is very difficult to operate, and the result also just can obtain 80% purity.And this method can only separate the mixture that only contains 2,4-lutidine and 2,5-lutidine, but in fact is difficult to obtain such raw material.
The second, mention in the US Patent No. 2456377, when lutidine mixture during with dry hydrogen chloride gas salify, 2, the 4-lutidine can preferential salify, and in other words, the amount of using the hydrogenchloride that lacks than mixing lutidine raw material total mole number is salify with it, 2,4-lutidine purity is improved.In this method, used dry hydrogen chloride gas, if oneself produce, difficulty is very large, uses the hydrogenchloride steel cylinder, and industrial cost is very high.This method also can only obtain 2 of 95% purity, the 4-lutidine.
The third, 2510876 pairs of second methods of US Patent No. are improved, replace hydrogen chloride gas and 2 with concentrated hydrochloric acid, 4-lutidine salify, during salify, need reflux that the water in the reaction system is divided to fall by water trap, when moisture nearly separates terminal point, hydrochloride is separated out, again by filtering or centrifugal method, with hydrochloride (mainly being 2,4-dimethyl pyrazole thiamine hydrochloride) and the lutidine of salify not (a small amount of 2,4-lutidine and most 2,5-lutidine and other lutidine) separate.The hydrochloride solid that obtains is free with highly basic again, such as sodium hydroxide solution, thereby obtain purity be 94%～97% 2, the 4-lutidine.Also mention in this method, if need the product of 99% above purity, need again with the phosphoric acid salify once, further purification.This method obviously is of practical significance than front two kinds of methods, but shortcoming is yield low (being up to 50%), purity not high enough (being generally 94%～97%) is purified to more than 99%, need to again become salt refining with phosphoric acid, whether key is not provide reference example in the patent, do not know feasible.
In view of the problem of above existence, invent the extraction high purity 2 that a kind of practicality is good, operating performance is higher, the method for 4-lutidine is imperative.
Summary of the invention
The technical problem to be solved in the present invention mainly is: the method yield that relates to separation 2,4-lutidine in the prior art is low, purity is not high enough.
The present invention extracts 2 for solving in the aforesaid method three, and the poor technical problem of yield low-purity of 4-lutidine has been done some important improvement.The present invention has used and has been almost 2, the hydrochloric acid of 4-lutidine equivalent, rather than 0.5 equivalent in the method three, used the toluene of polarity as solvent, but not the nonpolar petroleum naphtha that adopts in the aforesaid method three, finally obtain 2, the purity of 4-lutidine is more than 93%, yield can reach more than 95%.
To achieve these goals, the invention provides a kind of extraction high purity 2, the method for 4-lutidine may further comprise the steps:
At first, choose purity and be 20%～70% 2,4-lutidine raw material adds the solvent of 1～10 times of crude pyridine quality therein.
Temperature is controlled between 40～100 ℃ and 30%～39% hydrochloric acid of 0.1～2.0 times of quality is added drop-wise in the reaction flask, after hydrochloric acid dropwises, is warming up to backflow, minute water.
When telling the water of 0.1～2.0 times of weight, stopped heating, be cooled to 0～60 ℃ after, solid is separated out, and filters.
To 2, impurity in the 4-lutidine crystal of hydrochloride is processed, and washed salt crystallization is put in the toluene solvant of 0.5～10 times of crystalline quality, with toluene solvant washing 2,4-dimethyl pyrazole thiamine hydrochloride, twice of other conditions and step repetition same as described above.
Free with 10%～50% sodium hydroxide solution to 2,4-dimethyl pyrazole thiamine hydrochloride, minute oil-yielding stratum, the reject water layer, this moment 2,4-lutidine purity is 85%～95%.
With 2 of 85%～95% purity obtained above, the 4-lutidine is raw material, repeats above steps, can obtain 2 of 98% above purity, the 4-lutidine.
In provided by the invention one preferred enforcement, the solvent that uses in the described step 1 comprises toluene, benzene or its mixture.
In provided by the invention one preferred enforcement, described method also comprises rectification step, cuts 157～159 fractions and obtains purity 2,4-lutidine more than 98%.
In provided by the invention one preferred enforcement, choose 2 of 60% left and right sides content in the described step 1,4-lutidine raw material is best.
In provided by the invention one preferred enforcement, the solvent that adds 2 times of quality in the described step 1 is best.
In provided by the invention one preferred enforcement, temperature is controlled at below 80 ℃ in the described step 2, and the hydrochloric acid quality of adding is 0.8～2 times and is the best.
In provided by the invention one preferred enforcement, tell 0.2～0.3 times of water in the described step 3, be cooled to 20 ℃ and react best.
In provided by the invention one preferred enforcement, the solvent quality of washing is 2～3 times of the bests in the described step 4.
The invention has the beneficial effects as follows: among the present invention with purity be 93% 2,4-lutidine and concentrated hydrochloric acid be salify again, thereby has obtained 2 more than 99%, the 4-lutidine, twice salify total recovery is up to more than 85%.The more important thing is, in thick lutidine raw material, the content of 2,4-lutidine from 20% to 70% changes, and the experimental result difference is little, this has just obviously improved its industrial voltinism, because industrial method by rectifying obtains 70% left and right sides content 2, the thick lutidine raw material of 4-lutidine also is extremely difficult, and this need to be up to the reflux ratio more than 50, efficient is low, and energy consumption is high.
Embodiment
For the technological method that US Patent No. 2510876 provides, the present invention exists the yield technical problem low, purity difference of extracting 2,4-lutidine to improve to it.Used among the present invention and be almost 2, the hydrochloric acid of 4-lutidine equivalent, rather than 0.5 equivalent in US Patent No. 2510876 supplying methods, used the toluene of polarity as solvent, but not nonpolar petroleum naphtha, thereby obtain purity at 2 more than 93%, the 4-lutidine, yield is up to more than 95%.
Of the present inventionly improve crucial being: with purity be 93% 2,4-lutidine and concentrated hydrochloric acid be salify again, reaches 2 more than 99% thereby obtained purity, 4-lutidine product, twice salify total recovery is up to more than 85%.The more important thing is, in the thick lutidine raw material 2, the content of 4-lutidine changes from 20%～70%, the experimental result difference is little, and this has just obviously improved its industrial voltinism, because industrial method by rectifying obtains 70% left and right sides content 2, the thick lutidine raw material of 4-lutidine also is extremely difficult, this need to be up to the reflux ratio more than 50, and efficient is low, and energy consumption is high.
Embodiment 1:
In being furnished with the 500mL four-hole boiling flask of mechanical stirring and water-and-oil separator, adding 100g crude pyridine raw material and (contain 60% 2,4-lutidine, 0.93M) with 150mL toluene.
Under constantly stirring, will control temperature below 80 ℃, slowly 37% hydrochloric acid (55g, 0.56M) is added drop-wise in the reaction flask.Drip and finish, be warming up to backflow, minute water.After 25mL water was removed in reduction of a fraction, the bottle wall had solid to separate out, and reaction is reached home, stopped heating.
After being cooled to room temperature, there are a large amount of solids to separate out, filter, filter cake toluene wash (200 * 3).Filter cake is free with 20% sodium hydroxide solution, minute oil-yielding stratum, and the reject water layer obtains 2,4-lutidine product 60g, yield 100%, purity is 93.5%.
In being furnished with the 500mL four-hole boiling flask of mechanical stirring and water-and-oil separator, add purity obtained above and be 93.5% 2,4-lutidine (60g, 0.56M) and 150mL toluene.
Under constantly stirring, the control temperature slowly is added drop-wise to 37% hydrochloric acid (55g, 0.56M) in the reaction flask below 80 ℃.Drip and finish, be warming up to backflow, minute water.After 25mL water was removed in reduction of a fraction, the bottle wall had solid to separate out, and reaction is reached home, stopped heating.
After being cooled to room temperature, there are a large amount of solids to separate out, filter, filter cake toluene wash (200 * 3).Filter cake is free with 20% sodium hydroxide solution, minute oil-yielding stratum, and the reject water layer obtains 2,4-lutidine product 58g.Again rectifying cuts 157～159 fractions, gets 2,4-lutidine 49.8%, total recovery: 83%, and purity: 99.6%.
Embodiment 2
In being furnished with the 500mL four-hole boiling flask of mechanical stirring and water-and-oil separator, adding 100g crude pyridine raw material and (contain 20% 2,4-lutidine, 0.18M) with 150mL toluene.
Under constantly stirring, will control temperature below 80 ℃, slowly 37% hydrochloric acid (17g, 0.18M) is added drop-wise in the reaction flask.Drip and finish, be warming up to backflow, minute water.After 10mL water was removed in reduction of a fraction, the bottle wall had solid to separate out, and reaction is reached home, stopped heating.
After being cooled to room temperature, there are a large amount of solids to separate out, filter, filter cake toluene wash (100 * 3).Filter cake is free with 20% sodium hydroxide solution, minute oil-yielding stratum, and the reject water layer obtains 2,4-lutidine product 20g, yield 100%, purity is 90.5%.
In being furnished with the 500mL four-hole boiling flask of mechanical stirring and water-and-oil separator, add purity obtained above and be 90.5% 2,4-lutidine (60g, 0.56M) and 200mL toluene.
Under constantly stirring, the control temperature slowly is added drop-wise to 37% hydrochloric acid (17g, 0.18M) in the reaction flask below 80 ℃.Drip and finish, be warming up to backflow, minute water.After 10mL water was removed in reduction of a fraction, the bottle wall had solid to separate out, and reaction is reached home, stopped heating.
After being cooled to room temperature, there are a large amount of solids to separate out, filter, filter cake toluene wash (100 * 3).Filter cake is free with 20% sodium hydroxide solution, minute oil-yielding stratum, and the reject water layer obtains 2,4-lutidine product 58g.Again rectifying cuts 157～159 fractions, gets 2,4-lutidine 16g, total recovery: 80%, and purity: 99.2%.
The description of above preferred embodiment makes those skilled in the art can make or use the present invention.The various modifications of these embodiment are apparent for a person skilled in the art, and the General Principle of definition can be applied among other embodiment and do not deviate from the spirit or scope of the present invention here.Therefore, the present invention is not limited to shown here embodiment, and will meet the most wide in range scope consistent with the principle that discloses and novel feature here.
Claims (8)
1. one kind is extracted high purity 2, and the method for 4-lutidine is characterized in that, may further comprise the steps:
Step 1, purity be 20%～70% 2, in the 4-lutidine raw material, add the solvent of 1～10 times of crude pyridine quality;
Step 2 is controlled at temperature between 40～100 ℃ and 30%～39% hydrochloric acid of 0.1～2.0 times of quality is added drop-wise in the reaction flask, after hydrochloric acid dropwises, is warming up to backflow, minute water;
Step 3, when telling the water of 0.1～2.0 times of weight, stopped heating, be cooled to 0～60 ℃ after, solid is separated out, and filters;
Step 4 is processed the impurity in 2, the 4-lutidine crystal of hydrochloride, washed salt crystallization is put in the toluene solvant of 0.5～10 times of crystalline quality, with toluene solvant washing 2,4-dimethyl pyrazole thiamine hydrochloride, twice of other conditions and step repetition same as described above;
Step 5, free with 10%～50% sodium hydroxide solution to 2,4-dimethyl pyrazole thiamine hydrochloride, minute oil-yielding stratum, the reject water layer, this moment 2,4-lutidine purity is 85%～95%;
Step 6 will be with 2 of 85%～95% purity obtained above, and the 4-lutidine is raw material, and the step of repeating step 2～5 namely obtains 2 of 98% above purity, the 4-lutidine.
2. method according to claim 1 is characterized in that: the solvent that uses in the described step 1 comprises toluene, benzene or its mixture.
3. method according to claim 1, it is characterized in that: described method also comprises rectification step, cuts the 157-159 fraction, obtains purity 2,4-lutidine more than 98%.
4. method according to claim 1 is characterized in that: choose 2 of 60% content in the described step 1,4-lutidine raw material.
5. method according to claim 1 is characterized in that: the solvent that adds 2 times of quality in the described step 1.
6. method according to claim 1, it is characterized in that: temperature is controlled at below 80 ℃ in the described step 2, and the hydrochloric acid quality of adding is 0.8～2 times.
7. method according to claim 1 is characterized in that: tell 0.2～0.3 times of water in the described step 3, be cooled to 20 ℃ and react.
8. method according to claim 1 is characterized in that: the solvent quality of washing is 2～3 times in the described step 4.
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| CN2013100445157A CN103058915A (en) | 2013-02-05 | 2013-02-05 | Method for extracting high-purity 2,4-dimethyl pyridine |
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| CN2013100445157A CN103058915A (en) | 2013-02-05 | 2013-02-05 | Method for extracting high-purity 2,4-dimethyl pyridine |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107382830A (en) * | 2017-08-17 | 2017-11-24 | 滨海金海立医药化工有限公司 | A kind of separation method for drawing pyridine derivate in azoles production |
| CN114804481A (en) * | 2022-04-15 | 2022-07-29 | 山东潍坊润丰化工股份有限公司 | Treatment method of pyridine-containing wastewater |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2320322A (en) * | 1943-05-25 | Process osi separating | ||
| US2456377A (en) * | 1948-12-14 | Process of separating z | ||
| US2510876A (en) * | 1950-06-06 | Recovery of z | ||
| CA472081A (en) * | 1951-03-13 | Henry Engel Karl | Recovery of 2,4-lutidine and 2,3-lutidine |
-
2013
- 2013-02-05 CN CN2013100445157A patent/CN103058915A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2320322A (en) * | 1943-05-25 | Process osi separating | ||
| US2456377A (en) * | 1948-12-14 | Process of separating z | ||
| US2510876A (en) * | 1950-06-06 | Recovery of z | ||
| CA472081A (en) * | 1951-03-13 | Henry Engel Karl | Recovery of 2,4-lutidine and 2,3-lutidine |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107382830A (en) * | 2017-08-17 | 2017-11-24 | 滨海金海立医药化工有限公司 | A kind of separation method for drawing pyridine derivate in azoles production |
| CN107382830B (en) * | 2017-08-17 | 2019-10-29 | 滨海金海立医药化工有限公司 | A kind of separation method drawing pyridine derivate in azoles production |
| CN114804481A (en) * | 2022-04-15 | 2022-07-29 | 山东潍坊润丰化工股份有限公司 | Treatment method of pyridine-containing wastewater |
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Application publication date: 20130424 |