Complexing Crystallization Separation purification meta-cresol technology
Technical field
The invention belongs to field of chemical separation and purification, relate to a kind of complexing crystallization process and separate purification meta-cresol technology.
Background technology
Cresols is important fine-chemical intermediate, comprise three kinds of isomer, promptly ortho-cresol, p-cresol, meta-cresol are domestic comparatively well sold and in short supply fine chemical product, especially domestic seriously supply falls short of demand to, meta-cresol, annually needs that import is a great deal of satisfies domestic market demand.Meta-cresol is widely used in fields such as agricultural chemicals, medicine, spices, dyestuff, oxidation inhibitor, stopper, UV light absorber, fuel dope, rubber ingredients, coating, fodder additives and synthetic materials.
Between, p-cresol is owing to boiling point separates with conventional method near being difficult to very much.Between, the separation method of p-cresol can be divided into physical method and chemical process generally.Physical method divides azeotropic distn, dissociation extraction method, high pressure crystal partition method, molecular sieve adsorption again: chemical process has class huge legendary turtle compound partition method, alkylation methods etc.
Shang Sihua etc. (chemical research and application, the 15th the 6th phase of volume) have proposed urea and meta-cresol eutectic method compartment/p-cresol; Yin Kailiang (Jiangsu Petrochemical Engineering College journal, the 11st the 2nd phase of volume) has studied the infrared spectra of urea and meta-cresol compound crystal.More than two pieces of articles to meta-cresol and urea crystallization in toluene solvant done introduction.More than research all is to make solvent with toluene.There are shortcomings such as the toluene consumption is big, productive rate is not high and the toluene boiling point is higher relatively, the recovery energy consumption is big in the solvent that toluene is done crystallization reaction.
US3855195A has introduced aromatics (toluene, vinylbenzene, chlorobenzene) when making solvent, the complexing crystallization reaction situation of urea and cresols.Set forth in the JP2010059137 by in cresols, adding urea and water, generated emulsion, method from emulsion from the separation and Extraction meta-cresol.Above-mentioned article is not all mentioned with alkane solvent in the very weak normal hexane of polarity particularly.
Summary of the invention
The object of the invention is to provide the processing method of the separation purification meta-cresol that a kind of solvent load is few, productive rate is high.
Now the present invention is summarized.
(1) dissolving of urea in mixing phenol: adding mixes phenol in reactor, to wherein adding a certain proportion of urea, by in water-bath or oil bath heating, urea is all dissolved and certain time in mixing phenol solution again.
(2) crystallization: along with the reduction of temperature, meta-cresol can and constantly be separated out with the crystalline form with complex compound that urea forms, and along with the increase of crystalline amount, the viscosity of mixture is also increasing.When temperature is reduced to a certain degree, in mixture, at the uniform velocity dripping a certain amount of normal hexane as solvent.
(3) crystal solution is separated: filter the xln that experiment produces, with the normal hexane washing leaching cake for several times, obtain the urea one meta-cresol complex compound crystal of white in the time of suction filtration.
(4) crystallisate pyrolysis: white crystal is placed on carries out pyrolysis in 40 ℃ in the water-bath, the meta-cresol that produces after the pyrolysis is present in organic phase, and urea then is dissolved in aqueous phase.
(5) separatory: to separating funnel, static layering treats that layering obviously separates lower floor's water in the back, gets upper organic phase and does purity assay the solution after the pyrolysis.
Complexing Crystallization Separation purification meta-cresol technology, it is characterized in that, step is as follows: the dissolving of urea in mixing phenol: add in reactor and mix phenol, mixed phenol contains ortho-cresol 10.907wt%, p-cresol 34.276wt%, meta-cresol 53.176wt%, xylenol 1.641%; To wherein adding urea, urea and meta-cresol mol ratio are 1.0-1.8 again; By at water-bath or oil bath heat temperature raising to 85-105 ℃, continue 40-80min, make urea all dissolvings in mixing phenol solution; Cooling adds the normal hexane in the normal hexane groove when 60 ℃ of temperature, the volume ratio of normal hexane and meta-cresol is 1-3; At the subzero 20 ℃ of crystallization 1-2 of subzero 10-hours, finish crystallization operation afterwards; Then slurry is sent in the strainer, finished the solid, liquid lock out operation; Filtrate rectifying is reclaimed, and crystalline solid adds entry, and heating obtains water and organic two-phase 40 ℃ of hydrolysis; Water reclaims, and organic phase is a meta-cresol.
With respect to toluene, the productive rate of meta-cresol is higher when making the solvent of complexing crystallization reaction with normal hexane, and the usage quantity of solvent can reduce 1/3rd.When solvent is reclaimed in rectifying, relatively low because of the boiling point of normal hexane, can use less relatively energy consumption with regard to recyclable solvent.
Description of drawings
Fig. 1 process flow sheet of the present invention.
Embodiment
In conjunction with the accompanying drawings the present invention is summarized in detail now.Accompanying drawing is the process flow sheet of complexing Crystallization Separation meta-cresol.Raw material mixes the mixed phenol of the storage of raw materials in the phenol groove.The raw material that reacts used mixes phenol and mainly contains ortho-cresol (10.907wt%), p-cresol (34.276wt%), meta-cresol (53.176wt%), xylenol (1.641%) for mixing the phenol isomer.Raw material mixes phenol and enters in the reactor, and simultaneously, urea is also put into reactor.Urea and meta-cresol mol ratio are 1.0-1.8.In reactor, be warming up to 85-105 ℃, continue 40-80min.Cooling adds the normal hexane in the normal hexane groove when 60 ℃ of temperature, the volume ratio of normal hexane and meta-cresol is 1-3.Afterwards, reaction solution enters crystallizer.Subzero 10-20 ℃ crystallization 1-2 hour, finish crystallization operation.Then slurry is sent in the strainer, finished the solid, liquid lock out operation.Filtrate enters rectifying tower, reclaims normal hexane by rectifying.The crystalline solid phase that is filtered out by strainer enters splitter, and the water in splitter adding tank decomposes about 40 ℃ simultaneously, obtains organic phase and water two-phase, and water reclaims, and organic phase is a meta-cresol.Whole technology has only raw material to mix the phenol inlet and by-product mixes phenol outlet and the outlet of product meta-cresol, and other normal hexanes, urea can be at system's internal recycle, and this flow process can be added the normal hexane and the urea of loss at any time.
Example (1)
In reactor, add raw material and mix phenol (the mixed phenol composition of raw material: ortho-cresol 10.907wt%, p-cresol 34.276wt%, meta-cresol 53.176wt%, xylenol 1.641%), add complexing agent urea again, the mol ratio that its add-on and raw material mix meta-cresol in the phenol is 1.4: 1, puts into oil bath, be warming up to 95 ℃, reacted one hour.After reaction is finished, when question response liquid is cooled to 60 ℃, drip normal hexane, the volume ratio that normal hexane consumption and raw material mix phenol is 2.Dropwise the back there-necked flask is placed in the low temperature thermostat bath,, filter after 1 hour-15 ℃ of maintenances, filtrate rectifying is reclaimed, and crystalline solid adds the deionized water of three times of quality, and heating hydrolysis obtains water and organic two-phase.Organic phase is the product meta-cresol.With gc analysis meta-cresol product.Experimental result sees Table 1.
[Comparative Examples] example 2 experimental installations and operation are with example (1), and just the solvent that drips is that toluene is while the volume ratio of the mixed phenol of toluene consumption and raw material is 3.Experimental result sees Table 1.
[Comparative Examples] example 3 experimental installations and operation are with example (2), and just crystallization time is 2 hours.Experimental result sees Table 1.
Example 4 experimental installations and operation are with example (1), and just crystallization time is 2 hours.Reaction result sees Table 1.
Example 5 experimental installations and operation are with example (1), and just the normal hexane consumption that drips is 3 with the volume ratio of the mixed phenol of raw material.Experimental result sees Table 1.
Example 6 experimental installations and operation are with example (1), and just the normal hexane consumption that drips is 1 with the specific volume ratio that raw material mixes phenol.Experimental result sees Table 1.
Example 7 experimental installations and operation are with example (1), and just the temperature of complex reaction is 105 ℃.Experimental result sees Table 1.
Example 8 experimental installations and operation together routine (1) the just temperature of complex reaction are 85 ℃.Reaction result sees Table 1.
Example 9 experimental installations and operation be with example (1), just and Tc be 2 hours for-10 ℃ and crystallization time.Experimental result sees Table 1.
Example 10 experimental installations and operation are with example (1), and just Tc is-20 ℃.Experimental result sees Table 1
Example 11 experimental installations and operation are with example (1), and just the reaction times is 40min, and experimental result sees Table 1
Example 12 experimental installations and operation are with example (1), and just the reaction times is 80min, and experimental result sees Table 1
Example 13 experimental installations and operation are with example (1), and just urea and meta-cresol mol ratio are 1.0: 1, and experimental result sees Table 1
Example 14 experimental installations and operation are with example (1), and just urea and meta-cresol mol ratio are 1.8: 1, the results are shown in Table 1
Table 1
The present invention produces a desired effect.When the effect during as the solvent of crystallization reaction with normal hexane will be significantly better than the time with toluene effect, and the relative toluene consumption of the consumption of normal hexane has reduced 1/3rd.When solvent is reclaimed in rectifying, relatively low because of the boiling point of normal hexane, can use less relatively energy consumption with regard to recyclable solvent.