CN104058936A - Method for separation and purification of p-cresol - Google Patents
Method for separation and purification of p-cresol Download PDFInfo
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- CN104058936A CN104058936A CN201410280902.5A CN201410280902A CN104058936A CN 104058936 A CN104058936 A CN 104058936A CN 201410280902 A CN201410280902 A CN 201410280902A CN 104058936 A CN104058936 A CN 104058936A
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- cresol
- oxalic acid
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- C07—ORGANIC CHEMISTRY
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- C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
- C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
- C07C37/685—Processes comprising at least two steps in series
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Abstract
The invention discloses a method for separation and purification of p-cresol. The method comprises the following steps: 1) complexation: adding toluene and a complexing agent of oxalic acid into a reaction kettle, heating, adding mixed cresol, insulating for reaction, and filtering to obtain a cresol- oxalic acid complex crude product; 2) purification: adding the p-cresol-oxalic acid complex crude product into a purification solvent, stirring and filtering to obtain a p-cresol-oxalic acid complex; 3) decomplexation: adding the p-cresol-oxalate complex into water, insulating for reaction, separating an upper organic phase while hot, extracting the lower aqueous phase by toluene, and merging the extraction liquid into the upper organic phase; and 4) distillation: distilling the upper organic phase to remove solvent so as to obtain p-cresol. Compared with the prior art, a purification step is added to ensure that the final isolated p-cresol has purity of no less than 99%; the amount of organic solvents is reduced, the complexation step employs water, and the organic solvent and water involved in the separation process can be used indiscriminately, thereby saving cost.
Description
Technical field
The present invention relates to a kind of method of separation industries p-cresol and meta-cresol mixture, be specifically related to that a kind of to take industrial p-cresol and meta-cresol mixture be raw material, by selecting Separation by Complexation method to purify, obtain the method for p-cresol.
Background technology
Phenol and methyl alcohol carry out the methylation reaction of phenol under solid catalyst effect, and product is cresols, mainly contains ortho-cresol, p-cresol and meta-cresol, and the xylenol of trace.The development of chemical industry and the exploitation of product innovation are had higher requirement to the purity of p-cresol.By rectifying, can isolate ortho-cresol, residual mother liquor comprises p-cresol, meta-cresol and a small amount of xylenol.Because of between/atmospheric boiling point of p-cresol differs and is less than 1.0 ℃, be difficult to carry out separation in the mode of rectifying.At present/separation method of p-cresol comprises physical method and the large class of chemical process two.Physical method has azeotropic distn, high pressure crystal partition method and molecular sieve absorption process; Chemical process has the derivative separation such as class inner complex partition method, alkylation.Wherein, molecular sieve absorption process is because molecular sieve is selected and preparation difficulty, and adsorptive capacity is limited, employing also less; Azeotropic distn is under the existence of p-cresol sodium, and p-cresol can steam with water azeotropic, and energy consumption is too large; High pressure crystal partition method needs the pressure of 100～300MPa, too high to equipment requirements, and investment is too many; Alkylation partition method needs alkylation and de-alkyl, high vacuum rectification etc., and equipment is comparatively complicated, invests greatlyr, and cost is higher; Class inner complex partition method is simple to operate, and raw material is easy to get, and various raw material reusable edible.
CN 1127241A report, usings piperazine or Uricida as extraction agent, and n-butyl ether, isopropyl ether or isoamyl oxide are made solvent, separating-purifying p-cresol from cresols.Yet this technique need to reclaim piperazine and bring very large energy consumption from water, and adopts expensive ether solvent, is difficult to realize industrialization.In US4394526, reported by inorganic salt (CaBr
2, LiBr, MgBr
2and MgCl
2) p-cresol in selectivity and cresols generates complex compound and realize separation and Extraction p-cresol from cresols, yet, in whole separating technology, adopting a large amount of low boiling point organic solvents, this technique does not possess the good market competitiveness.CN 103333052 report, adopts oxalic acid to isolate p-cresol from cresols (meta-cresol 58.5wt%, p-cresol 27.8wt%, 2,4-xylenol 5.7wt%, 2,5-xylenol 4.2wt%, and part ortho-cresol, phenol, ethyl phenol).But there are some shortcomings in the method:
1) in cresols, p-cresol content is less, only has 27.8wt%, and Oxalic Acid Method is used limited, cannot give play to best effect;
2) in reaction process, use volatile low boiling point solvent, as hexanaphthene, sherwood oil, thus increased the loss of solvent, and that solvent loss accounts for the proportion of process costs is maximum;
3) p-cresol-oxalate complex does not pass through purifying, directly separates complexing, and the quality index of the p-cresol obtaining is difficult to reach the requirement of relevant criterion;
4) in complex reaction, conciliate in complexation process and use two kinds of different organic solvents, between solvent, be difficult to realize effective separation, thereby increased the complexity of actually operating.
Summary of the invention
Technical problem to be solved by this invention is, provide a kind of by/mixture of p-cresol obtains pure p-cresol, and can realize the method for separated p-cresol and the meta-cresol mixture of circulation Separation by Complexation through disposable separation.
For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of method of separated p-cresol and meta-cresol mixture, the steps include:
1) complexing: add toluene and complexing agent oxalic acid in reactor, be warming up to 60～70 ℃, add cresols, insulation reaction 1～3h, filters, and obtains p-cresol-oxalate complex crystal crude product of filtrate and white fine particulate;
The add-on of described toluene is 2.1 ± 0.2 times of cresols quality, and described oxalic acid add-on is 1.0 ± 0.1 times of p-cresol molar weight in cresols;
2) p-cresol-oxalate complex crystal crude product purifying: by step 1) joins in purification solvent, stirs 1 ± 0.5h, filters, and obtains p-cresol-oxalate complex sterling;
3) solution complexing: by step 2) p-cresol-oxalate complex sterling of gained is added to the water, be warming up to 40～80 ℃, insulation reaction 1.5 ± 0.5h, (40～80 ℃) isolate upper organic phase while hot, lower floor's water extracts with toluene, and extraction liquid is incorporated to upper organic phase;
4) solvent is removed in upper organic phase distillation distillation: by step 3), obtains p-cresol, and the toluene distilling out is applied mechanically to step 1) or step 3) in;
5) the lower floor's water recovery complexing agent: by step 3) distills to obtain oxalic acid, applies mechanically to step 1), water is back to step 3) in.
Step 1) in, described cresols comprises p-cresol, meta-cresol and 2,6-xylenol, and it consists of: p-cresol 10～90wt.%, meta-cresol 10～90wt.%, 2,6-xylenol, 0～5wt.%.
Step 1), in, described complexing agent oxalic acid is anhydrous oxalic acid or two oxalic acid hydrates.
In step 2) in, the mixture that purification solvent is toluene-methyl alcohol, wherein the volume content of methyl alcohol is 1%～20%, is preferably 2%～10%.
Step 2) in, during filtration, the temperature of purification solvent is 0～24 ℃, is preferably 0～5 ℃.
Step 2), in, the quality of purification solvent is 1～4 times of p-cresol-oxalate complex crude product quality, is preferably 1～2 times.
Step 3), in, the consumption of separating water in complex reaction is 1～5 times of p-cresol-oxalate complex quality, is preferably 1～3 times.
Step 3), in, the temperature of separating complex reaction is preferably 45～55 ℃.
The disclosed technical scheme of the application has following advantage: with respect to previous separation method, the present invention has increased purification step, for the high purity of complexation-crystallization method separated product p-cresol provides safeguards.And the present invention adopts water as solvent in separating complexing step, greatly reduce process costs.Circulation Separation by Complexation method is a kind of environmentally friendly green separation method, the equal recycled of the toluene adopting in Separation by Complexation technique and water, and omnidistance separating technology does not have the discharge of the three wastes.
In addition, in the cresols that the present invention uses, the content of p-cresol is 71.3wt%, and example shows, than previous separation method, the present invention has obtained better separating effect.
In addition, present method can at utmost be extracted and isolate p-cresol, thereby makes the abundant enrichment of meta-cresol in surplus stock, and quality percentage composition is increased to 82.0～84.6% from 28.2%, can be used as the raw material of separation and Extraction meta-cresol.
Embodiment
Embodiment 1
The self-produced cresols of Chemical Group that circles in the air of take is raw material, comprising p-cresol 71.3wt%, and meta-cresol 28.2wt%, 2,6-dimethyl cresols 0.5wt%.First, in glass there-necked flask, add toluene and oxalic acid (Anhui anhydrous oxalic acid company limited), oxalic acid add-on is 1.0 times of p-cresol molar weight in raw material cresols, the add-on of toluene is 2.1 times of cresols quality, be heated to 70 ℃, add cresols, add insulation reaction 2h, be cooled to 5 ℃, crystallization 1h.Solid-liquid separation, solid is p-cresol-oxalate complex crude product, filtrate is the toluene solution of enrichment meta-cresol.P-cresol-oxalate complex crude product is joined in toluene-methyl alcohol, wherein the volume content of methyl alcohol is 4%, and the consumption of mixed solvent is 1 times of p-cresol-oxalate complex crude product quality, and 5 ℃ are stirred 1h, solid-liquid separation, solid is p-cresol-oxalate complex sterling that purity is greater than 99%.P-cresol-oxalate complex sterling is added to the water, and the add-on of water is 2.6 times of p-cresol-oxalate complex quality, is warming up to 50 ℃, and hydrolysis 1h, isolates upper organic phase while hot, and lower floor's water extracts with toluene, and extraction liquid is incorporated to upper organic phase.Organic phase is steamed and is desolventized toluene, obtains pure p-cresol, and recovered solvent toluene is applied mechanically to the hydrolysis reaction of next round.Water is removed in water distillation, and the anhydrous oxalic acid obtaining is applied mechanically the complex reaction to next round.
The compositional analysis of p-cresol extraction efficiency, p-cresol purity, cresols the results are shown in Table 1
Embodiment 2
Experimental installation and operation, with embodiment 1, only replace with anhydrous oxalic acid two oxalic acid hydrates, add the molar weight of two oxalic acid hydrates constant.
Embodiment 3
Experimental installation and operation, with embodiment 1, only change purification step into: the mixture that purification solvent is toluene-methyl alcohol.Wherein the content of methyl alcohol is 2%, and purification solvent consumption is 1.5 times of p-cresol-oxalate complex crude product, and filtration temperature is 0 ℃.
Embodiment 4
Experimental installation and operation, with embodiment 1, only change purification step into: the mixture that purification solvent is toluene-methyl alcohol.Wherein the content of methyl alcohol is 2%, and purification solvent consumption is 2 times of p-cresol-oxalate complex crude product, and filtration temperature is 5 ℃.
Embodiment 5
Experimental installation and operation, with embodiment 1, only change purification step into: the mixture that purification solvent is toluene-methyl alcohol.Wherein the content of methyl alcohol is 3%, and purification solvent consumption is 2 times of p-cresol-oxalate complex crude product, and filtration temperature is 3 ℃.
Embodiment 6
Experimental installation and operation, with embodiment 1, only change into separating complexing step: the consumption of water is 2 times of p-cresol-oxalate complex sterling quality, and hydrolysising reacting temperature is 45 ℃.
Embodiment 7
Experimental installation and operation, with embodiment 1, only change into separating complexing step: the consumption of water is 3 times of p-cresol-oxalate complex sterling quality, and hydrolysising reacting temperature is 50 ℃.
Embodiment 8
Experimental installation and operation are with embodiment 1, only by step 1) mesoxalic acid use recovery oxalic acid.
Embodiment 9
Experimental installation and operation are with embodiment 1, only by step 1) middle toluene use recovery toluene.
Embodiment 10
Experimental installation and operation are with embodiment 1, only by step 3) in water use recycle-water.
Table 1
| Embodiment | P-cresol extraction efficiency | P-cresol purity | M-and P-cresols ratio in complexing mother liquor |
| Embodiment 1 | 92.7％ | 99.4％ | 82.9％：15.6％ |
| Embodiment 2 | 90.5％ | 99.5％ | 80.1％：16.3％ |
| Embodiment 3 | 91.5％ | 99.3％ | 82.9％：15.6％ |
| Embodiment 4 | 87.6％ | 99.4％ | 82.9％：15.6％ |
| Embodiment 5 | 87.5％ | 99.5％ | 82.9％：15.6％ |
| Embodiment 6 | 92.0％ | 99.3％ | 82.9％：15.6％ |
| Embodiment 7 | 93.2％ | 99.3％ | 82.9％：15.6％ |
| Embodiment 8 | 92.5％ | 99.3％ | 82.5％：15.8％ |
| Embodiment 9 | 92.6％ | 99.2％ | 82.3％：16.2％ |
| Embodiment 10 | 92.9％ | 99.4％ | 82.9％：15.6％ |
The present invention has realized following effect:
1. present method has increased purification step, and the purity that separation obtains product p-cresol is 99.1～99.5%.Meet the index request of the JIS K8306-2013 of Japanese Industrial Standards.
2. complexing agent adopts cheap oxalic acid or two oxalic acid hydrates, has reduced process costs.
3. the complexing agent oxalic acid, the solvent toluene that in present method, reclaim all can be recycled, and reduce three waste discharge.
4. the by product that present method obtains is rich in meta-cresol, can be used as the raw material of separation and Extraction meta-cresol.
Claims (8)
1. a method for separating-purifying p-cresol, comprises the following steps:
1) complexing: add toluene and complexing agent oxalic acid in reactor, be warming up to 60～70 ℃, add the cresols of purification to be separated, insulation reaction 1～3h, filters, and obtains filtrate and p-cresol-oxalate complex crude product;
The add-on of described toluene is 2.1 ± 0.2 times of cresols quality, and described oxalic acid add-on is 1.0 ± 0.1 times of p-cresol molar weight in cresols;
2) p-cresol-oxalate complex crude product purifying: by step 1) adds in purification solvent, stirs 1 ± 0.5h, filters, and obtains p-cresol-oxalate complex;
Described purification solvent is the mixture of toluene and methyl alcohol, and wherein the volume content of methyl alcohol is 1%～20%;
3) p-cresol-oxalate complex solution complexing: by step 2) is added to the water, and is warming up to 40～80 ℃, and insulation reaction 1.5 ± 0.5h isolates upper organic phase under 40～80 ℃ of conditions, and lower floor's water extracts with toluene, and extraction liquid is incorporated to upper organic phase;
4) solvent is removed in upper organic phase distillation distillation: by step 3), obtains p-cresol.
2. the method for a kind of separating-purifying p-cresol according to claim 1, it is characterized in that: the step of described separating-purifying p-cresol also comprises: by step 3) in lower floor's water of obtaining distill, gained oxalic acid is applied mechanically to step 1), gained water is back to step 3) in; By step 4) toluene that obtains in still-process applies mechanically to step 1) or step 3) in.
3. the method for a kind of separating-purifying p-cresol according to claim 1, is characterized in that: step 1) in, the cresols of described purification to be separated, it consists of: p-cresol 10～90wt.%, meta-cresol 10～90wt.%, 2,6-xylenol, 0～5wt.%.
4. the method for a kind of separating-purifying p-cresol according to claim 1, is characterized in that: step 1) in, described complexing agent oxalic acid is anhydrous oxalic acid or two oxalic acid hydrates.
5. the method for a kind of separating-purifying p-cresol according to claim 1, is characterized in that: step 2) in, in described filtration procedure, purification solution temperature is 0～24 ℃.
6. the method for a kind of separating-purifying p-cresol according to claim 1, is characterized in that: step 2) in, the quality of described purification solvent is 1～4 times of p-cresol-oxalate complex crude product quality.
7. the method for a kind of separating-purifying p-cresol according to claim 1, is characterized in that: step 3) in, in described solution complex reaction, the quality of water is 1～5 times of p-cresol-oxalate complex quality.
8. the method for a kind of separating-purifying p-cresol according to claim 1, is characterized in that: step 3) in, the temperature of described solution complex reaction is 50 ± 5 ℃.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107057114A (en) * | 2017-05-19 | 2017-08-18 | 江苏飞亚化学工业有限责任公司 | A kind of emulsion-type high dispersive antioxidant |
| CN107118387A (en) * | 2017-05-19 | 2017-09-01 | 江苏飞亚化学工业有限责任公司 | A kind of composite type antioxidant agent |
| CN115304456A (en) * | 2022-08-09 | 2022-11-08 | 宁夏派可威生物科技有限公司 | Separation process for separating metacresol from urea |
| CN115636735A (en) * | 2022-10-27 | 2023-01-24 | 北京化工大学 | Process method for extracting and separating m-cresol and p-cresol mixture |
Citations (1)
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| CN103333052A (en) * | 2013-07-25 | 2013-10-02 | 北京旭阳化工技术研究院有限公司 | Method for preparing pure p-cresol and pure m-cresol by separating industrial mixed p-cresol and m-cresol |
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103333052A (en) * | 2013-07-25 | 2013-10-02 | 北京旭阳化工技术研究院有限公司 | Method for preparing pure p-cresol and pure m-cresol by separating industrial mixed p-cresol and m-cresol |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107057114A (en) * | 2017-05-19 | 2017-08-18 | 江苏飞亚化学工业有限责任公司 | A kind of emulsion-type high dispersive antioxidant |
| CN107118387A (en) * | 2017-05-19 | 2017-09-01 | 江苏飞亚化学工业有限责任公司 | A kind of composite type antioxidant agent |
| CN115304456A (en) * | 2022-08-09 | 2022-11-08 | 宁夏派可威生物科技有限公司 | Separation process for separating metacresol from urea |
| CN115304456B (en) * | 2022-08-09 | 2023-09-22 | 宁夏派可威生物科技有限公司 | Separation process for separating m-cresol from urea |
| CN115636735A (en) * | 2022-10-27 | 2023-01-24 | 北京化工大学 | Process method for extracting and separating m-cresol and p-cresol mixture |
| CN115636735B (en) * | 2022-10-27 | 2024-05-28 | 北京化工大学 | A process for extracting and separating a mixture of m-p-cresol |
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