CN108911956B - Purification process of cracking by-product in condensation reaction - Google Patents
Purification process of cracking by-product in condensation reaction Download PDFInfo
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Abstract
The invention provides a purification process of cracking byproducts in condensation reaction, which comprises the following steps of preparing an organic fraction and purifying in the condensation reaction: washing, removing high-temperature reaction and a light component removal tower sequentially by products generated in the process of preparing 3, 5-dimethylphenol from isophorone, mixing NaOH solution with the concentration of 5% with front fraction of the light component removal tower at the temperature of 30-40 ℃ to enable phenolic substances in the NaOH solution to react with alkali to generate sodium phenolate dissolved in a water phase and an organic phase insoluble in the water phase, washing the organic phase at normal temperature, and then carrying out phase separation to obtain an organic phase as an organic fraction; purification in the condensation reaction: and carrying out Michael addition and elimination reaction on the organic fraction, acetone, water and a catalyst in a reactor to generate isophorone, and sequentially carrying out first-step normal-pressure light removal, second-step normal-pressure light removal, third-step reduced-pressure light removal, heavy-weight removal and impurity removal on a reacted mixture in a normal-pressure distillation tower to extract mesitylene and isophorone.
Description
Technical Field
The invention belongs to a purification process, and particularly relates to a purification process of cracking byproducts mesitylene and mesityl oxide in a condensation reaction.
Background
Isophorone (Isophorone, ISO) is the product of the condensation of acetone, with a chemical name: 3,5, 5-trimethyl-2-cyclohexen-1-one, molecular formula: C9H14O, molecular weight: 138.21, colorless or light yellow transparent liquid, high boiling point, low hygroscopicity, good solubility, dispersibility, and leveling property, and is a good solvent for polymer materials, and can dissolve nitrocellulose, acrylic acid ester, alkyd resin, polyester, epoxy resin, etc. Because of the same unsaturated structure, the double bond can further react to generate important products such as alcohol, acid, amine, ester, isocyanate and the like, and the double bond has wide application in industries such as plastics, pesticides, medicines, coatings and the like.
3, 5-dimethylphenol is white crystals. Molecular formula is C8H10O, molecular weight 122.17, melting point: 63-66 ℃, boiling point: 222 ℃, density: 0.968, CAS 108-68-9, dissolved in water and ethanol. For the manufacture of phenolic resins, pharmaceuticals, insecticides, dyes and explosives; the intermediate is used for preparing carbamate pesticide-carboximidamide, can be used for producing rubber accelerators, anti-aging agents, medicaments, spices, phenolic resin and the like, can be used as an additive of steel rolling cold rolling oil, and can prolong the service life of the cold rolling oil; it can be used for producing pesticide, rubber accelerator, antiaging agent, medicine, perfume, phenolic resin, etc. And the additive is also used as an additive of cold rolling oil for steel rolling, and can prolong the service life of the cold rolling oil.
The reaction process for preparing 3, 5-dimethylphenol by aromatizing isophorone is mainly carried out by two competitive routes. One of the processes is a phenolic ketone rearrangement process after the demethanization of isophorone, and 3, 5-dimethylphenol is mainly generated; the other process is the decomposition process of isophorone, which can generate various byproducts such as 1,3, 5-trimethylbenzene, m-xylene, toluene, m-cresol, diacetone alcohol, mesityl oxide, acetone and the like.
The reaction formula for preparing 3, 5-dimethylphenol by aromatizing isophorone is as follows:
acetone is firstly condensed to generate diacetone alcohol in the presence of strong base, then is dehydrated to generate mesityl oxide, and then is condensed, cyclized and dehydrated with acetone to obtain isophorone, and the selectivity and the conversion rate in the process are both lower. A large amount of patents and literature data are available at home and abroad to study the reaction mechanism of the method, and a large amount of detailed and meticulous work is also performed on the optimization of technological process parameters.
From the reported data, no patent and literature data are reported on the application of mesitylene and mesityl oxide generated in the process of preparing 3, 5-dimethylphenol from isophorone serving as a raw material in acetone condensation reaction, and the intensive research on the aspect is in a blank state.
Therefore, the method has positive significance for applying the two byproducts, namely mesitylene and mesityl oxide, generated in the process of generating 3, 5-dimethylphenol by arylation to the research of the process for preparing isophorone by acetone condensation, can realize the full utilization of the auxiliary materials and also can properly improve the yield of the reaction by reasonably optimizing the process, and has obvious economic significance.
Disclosure of Invention
The invention aims to provide a purification process of cracking byproducts in condensation reaction, which has higher reaction yield.
According to one aspect of the present invention, there is provided a process for purifying a cleavage by-product in a condensation reaction, comprising
Preparation of organic fraction: washing a product generated in the process of preparing 3, 5-dimethylphenol from isophorone to obtain a washed organic phase, performing weight removal treatment on the washed organic phase in a weight removal tower to obtain a weight removal organic phase, performing weight removal treatment on the weight removal organic phase in a light removal tower to obtain a light removal kettle liquid and a light removal front fraction for refining 3, 5-dimethylphenol, and washing an organic phase generated by the reaction of a 5% NaOH solution and the light removal front fraction to obtain an organic fraction;
purification in the condensation reaction: carrying out Michael addition and elimination reaction on the organic fraction, acetone, process water and a catalyst in a reactor to generate isophorone, carrying out first-step heat-source-free lightness removing treatment on the reacted mixture in an atmospheric distillation tower to obtain a first-step lightness removing product, continuously carrying out second-step atmospheric lightness removing treatment on the first-step lightness removing product in the atmospheric distillation tower to obtain a second-step lightness removing kettle liquid, carrying out third-step reduced lightness removing treatment on the second-step lightness removing kettle liquid in a reduced pressure distillation tower to obtain a third-step lightness removing kettle liquid, carrying out weight removing treatment on the third-step lightness removing kettle liquid in a weight removing tower to obtain a weight removing extracted liquid, wherein the weight content of the weight removing extracted liquid is not higher than 2%,
the heavy extraction liquid is subjected to impurity removal treatment in an impurity removal tower, impurity removal front fraction is collected under the conditions that the kettle temperature is not higher than 120 ℃, the top temperature is 90-100 ℃, the vacuum degree is-0.09 MPa and the pressure difference is 6-8Kpa, and is used as a raw material for extracting mesitylene or directly used as a composite organic solvent, the fraction of which the main component is mesitylene is extracted under the conditions that the kettle temperature is 120-125 ℃, the top temperature is 100-105 ℃, the vacuum degree is-0.095 MPa and the pressure difference is 6-8Kpa, and the fraction of which the main component is isophorone is extracted under the conditions that the kettle temperature is 130-150 ℃, the top temperature is 110-120 ℃, the vacuum degree is-0.098 MPa and the pressure difference is 6-8 Kpa.
In some embodiments, the organic fraction is free of phenolic substances and is liquid at room temperature, the main substance component comprises, by mass percent, 32-34% of mesitylene, 48-51% of mesitylene, and 15-20% of other components, the other components comprise 8-11% of acetone, 3-4% of diacetone alcohol, 2% of water, and the other components comprise 2-3% of water.
In some embodiments, the second atmospheric-pressure-lightness-removing overhead product is used as a raw material for the condensation reaction, and the third vacuum-lightness-removing overhead product is used as a raw material for the condensation reaction.
In some embodiments, the mesityl oxide is added during the preparation of isophorone.
In some embodiments, the flow ratio of acetone to organic fraction is 9:1 to 8:1, the feed flow of process water is controlled according to 15-20% of the total mass flow, the catalyst is 30% KOH solution, the amount of the catalyst is 0.1% of the total mass flow, the reaction temperature is 180-.
In some embodiments, the first step of the non-heat source light removal of the reaction liquid is carried out in an atmospheric distillation tower by using the reaction heat of 180-185 ℃, the kettle temperature is 120-130 ℃, the top temperature is 55-57 ℃, the removed products are mainly acetone and water, wherein the acetone is 95-98%, and the acetone is completely returned to the condensation reaction process to be used as the raw material.
In some embodiments, the second atmospheric light removal step is continuously performed in an atmospheric distillation tower, the temperature at the top of the tower is controlled to be 56-60 ℃, the extracted amount is controlled by adjusting the opening of a valve for heating steam, the micro-positive pressure in the tower is achieved, the pressure difference between the bottom of the tower and the top of the tower is 6-8Kpa, the temperature of the bottom of the tower is 70-80 ℃, the content of acetone in the bottom of the tower is controlled to be less than or equal to 5%, and the content of acetone in the material extracted from the top of the tower can reach more than 90%, and the whole material is returned to the condensation reaction process to be used as a raw material.
In some embodiments, the third step of pressure reduction and dehydration is performed in a reduced pressure rectification tower, the vacuum degree of the reduced pressure rectification tower is controlled to be-0.05-0.06 Mpa, the temperature of the top of the tower is 56-80 ℃, the temperature of the bottom of the tower is 70-100 ℃, the pressure difference is 6-8Kpa, the content of acetone in the bottom of the tower is controlled to be less than or equal to 1%, and the content of acetone in the material extracted from the top of the tower can reach 80-85% and is completely returned to the condensation reaction process to be used as a raw material.
In some embodiments, the mesitylene is purified by distillation: delivering the mesitylene in the crude product tank into a rectifying tower, and extracting the mesitylene with the content higher than 98 percent by adjusting the reflux ratio under the conditions of the kettle temperature of 120-130 ℃, the top temperature of 105-110 ℃, the vacuum degree of-0.098 Mpa and the pressure difference of 6-8Kpa to obtain a mesitylene finished product.
The beneficial effects are as follows: the invention applies the two byproducts of mesitylene and isopropylidene acetone generated in the process of generating 3, 5-dimethylphenol by aromatization to the process for preparing isophorone by acetone condensation, can realize the full utilization of auxiliary materials and properly improve the yield of reaction by the reasonable optimization of the process, and has obvious economic significance.
Drawings
FIG. 1 is a schematic flow diagram of a process for purifying a cleaved byproduct in a condensation reaction according to one embodiment of the present invention.
Detailed Description
3, 5-dimethylphenol is used as an important fine chemical product, the application range is wider and wider, and the preparation of 3, 5-dimethylphenol by catalytic cracking by using isophorone as a raw material is a very convenient and efficient production process. The isophorone can be cracked and dehydrated at high temperature to generate mesitylene, meanwhile, the isophorone can be decomposed to form mesityl oxide, the two byproducts have low total content in the cracking process, and the two byproducts are generally collected as industrial byproducts and are not deeply utilized. The method comprises the steps of treating the byproduct by a certain procedure to obtain an organic fraction with use value, and then adding the organic fraction into a process for preparing isophorone by acetone liquid phase condensation, so that raw materials and auxiliary materials are fully utilized.
FIG. 1 schematically shows a process for purifying a cleavage by-product in a condensation reaction according to an embodiment of the present invention. As shown in fig. 1, the purification process of the cleavage by-product in the condensation reaction includes preparation of an organic fraction and purification in the condensation reaction.
Definition of organic fraction: the organic phase mixed liquid rich in the by-products of the mesitylene and the mesitylene, which is obtained by treating all products generated in the process of preparing the 3, 5-dimethylphenol by catalytic cracking by using the isophorone through washing, removing heavy components, removing light components, alkalifying and washing and phase splitting, is called as the organic fraction. The organic fraction is characterized by containing no phenolic substances, is liquid at normal temperature, and comprises the main substance components of 32-34% of mesitylene, 48-51% of mesitylene and 15-20% of other components by mass percent, wherein the other components comprise 8-11% of acetone, 3-4% of diacetone alcohol, 2% of water and 2-3% of other components by mass percent.
Preparation of organic fraction: washing a product generated in the process of preparing 3, 5-dimethylphenol from isophorone to obtain a washed organic phase, performing weight removal treatment on the washed organic phase in a weight removal tower to obtain a weight removal organic phase, performing weight removal treatment on the weight removal organic phase in a light removal tower to obtain a light removal kettle liquid and a light removal front fraction for refining 3, 5-dimethylphenol, and washing an organic phase generated by the reaction of a 5% NaOH solution and the light removal front fraction to obtain an organic fraction. In particular the organic fraction acquisition process: all products generated in the process of preparing 3, 5-dimethylphenol by catalytic cracking by using isophorone as a raw material are washed, subjected to heavy component removal, light component removal, alkalization, water washing, acidification and phase separation to obtain a mixture rich in mesitylene and mesitylene.
And (3) washing process: washing a reaction product of isophorone at a high temperature (0.4-0.8% of mesitylene, 1.0-1.5% of mesitylene, 2.0-5.0% of isophorone, 90-94% of 3, 5-dimethylphenol and 1.0-3.0% of other components) under the action of process water, controlling the washing temperature to be 98-102 ℃, the pressure to be less than or equal to 0.05Mpa and the pH to be 9-10, directly carrying out continuous phase separation treatment in a washing tower after washing, obtaining an upper organic phase, sending the upper organic phase to the next step of de-weighting treatment, and sending a lower aqueous phase rich in a catalyst to a special catalyst recovery process for collection treatment.
The weight removal process comprises the following steps: removing the residue, carbon deposition and other substances generated in the high-temperature reaction process from the organic phase obtained from the upper layer of the washing tower in a de-heavy tower, wherein the de-heavy process conditions comprise a kettle temperature of 140-. And all organic matters extracted from the top of the heavy component removal tower enter the light component removal tower for secondary treatment.
And (3) a lightness removing process: rectifying the organic matter recovered from the top of the heavy component removal tower in a light component removal tower to respectively obtain a front fraction at the top of the tower and a bottom liquid, wherein the process parameters of the light component removal tower are that the tower kettle is at 140 ℃ plus one material, the tower top is at 110 ℃ plus one material, and the vacuum degree is-0.085 Mpa. The front fraction taken out from the top of the light component removal tower mainly comprises low boiling point fractions such as mesitylene, mesitylene and phenols, and the fractions contain phenols and need dephenolization treatment. The main component of the tower bottom liquid after light component removal is a crude product of 3, 5-dimethylphenol, and the crude product enters a refining process to extract a finished product of 3, 5-dimethylphenol.
Alkalization: mixing 5% NaOH solution with the front cut fraction of the light component removal tower at 30-40 ℃ to react the phenolic substances with alkali to generate sodium phenolate which is dissolved in a water phase, carrying out acidification phase separation on the water phase to separate out phenolic substances, and sending the separated phenolic substances to a 3, 5-dimethylphenol refining process. Whereas the water-insoluble organic phase needs to be washed with water.
Washing and phase splitting: because the organic phase in the last step contains a small amount of free alkali to be purified, the organic phase obtained after alkalization is washed at normal temperature and then subjected to phase separation, and the removal of the free alkali can cause subsequent material foaming and various side reactions, thereby generating uncontrollable danger. The organic phase after water washing and phase separation is the organic fraction. The main content of the organic fraction is about 80-85% without further treatment, and the organic fraction is directly used as a raw material to be mixed with acetone and fed into the condensation reaction.
Purification in the condensation reaction: carrying out Michael addition and elimination reaction on the organic fraction, acetone, water and a catalyst in a reactor to generate isophorone, carrying out first-step heat source-free lightness removing treatment on the reacted mixture in an atmospheric distillation tower to obtain a first-step lightness removing product, continuously carrying out second-step atmospheric lightness removing treatment on the first-step lightness removing product in the atmospheric distillation tower to obtain a second-step lightness removing kettle liquid, carrying out third-step reduced lightness removing treatment on the second-step lightness removing kettle liquid in a reduced pressure distillation tower to obtain a third-step lightness removing kettle liquid, carrying out weight removing treatment on the third-step lightness removing kettle liquid in a weight removing tower to obtain a weight removing extracted liquid, wherein the weight content of the weight removing extracted liquid is not higher than 2%,
the heavy extraction liquid is subjected to impurity removal treatment in an impurity removal tower, impurity removal front fraction is collected under the conditions that the kettle temperature is not higher than 120 ℃, the top temperature is 90-100 ℃, the vacuum degree is-0.09 MPa and the pressure difference is 6-8Kpa, and is used as a raw material for extracting mesitylene or directly used as a composite organic solvent, the fraction of which the main component is mesitylene is extracted under the conditions that the kettle temperature is 120-125 ℃, the top temperature is 100-105 ℃, the vacuum degree is-0.095 MPa and the pressure difference is 6-8Kpa, and the fraction of which the main component is isophorone is extracted under the conditions that the kettle temperature is 130-150 ℃, the top temperature is 110-120 ℃, the vacuum degree is-0.098 MPa and the pressure difference is 6-8 Kpa.
The organic fraction is subjected to Michael addition and elimination reaction in a reactor together with acetone, water and a catalyst to generate isophorone in the next step, and the process flow is condensation reaction-lightness removal-weight removal-impurity removal-rectification. The finished product mesitylene is obtained through the process flow.
Explanation of the condensation reaction process: the first reaction in the process of preparing isophorone by acetone condensation is that acetone is condensed to generate diacetone alcohol, then the diacetone alcohol is dehydrated to form mesityl oxide, and the third step is that the mesityl oxide is condensed with acetone to generate isophorone; on the other hand, a certain amount of mesitylene is also produced in the process of preparing isophorone by acetone condensation, the amount of the mesitylene is about 0.2-0.5% in normal production, and the mesitylene in the two parts is enriched and purified along with material flow to obtain a mesitylene finished product.
Condensation reaction: the flow ratio of the acetone to the organic fraction is 9: 1-8: 1, the feed flow of the process water is controlled according to 15-20% of the total mass flow to control the supplementary water flow, the catalyst is a KOH solution with the concentration of 30%, the dosage of the KOH solution is 0.1% of the total mass flow, the reaction temperature is 180-. After the reaction is finished according to the process conditions, the content of the reaction liquid is 74.59% of acetone, 6.33% of mesityl oxide, 0.88% of diacetone alcohol, 0.96% of mesitylene, 12.99% of isophorone, 2.23% of heavy components, 2.02% of other components, 19.34% of water, and the pH value is 9-10, and the reaction liquid is light yellow transparent liquid.
The light component removal process is carried out in three steps:
the first step is light removal without heat source: the reaction liquid is subjected to primary light component removal by utilizing reaction heat (180-185 ℃), the light component removal process is carried out in an atmospheric distillation tower, the kettle temperature is 120-130 ℃ (the reason that the temperature of the reaction liquid is high), the top temperature is 55-57 ℃, products removed in the process are mainly acetone and water, wherein the acetone is 95-98%, and the acetone is completely returned to the condensation reaction process to be used as a raw material. The discharge content of the kettle liquid is 48 percent of acetone, 12.95 percent of mesitylene, 1.96 percent of mesitylene, 1.83 percent of diacetone alcohol, 26.57 percent of isophorone, 4.56 percent of heavy components and 4.13 percent of the rest.
The second step is normal pressure lightness removing: the process is continuously carried out in an atmospheric distillation tower because the acetone content in the first-step kettle liquid is still high, the temperature of the top of the tower is controlled to be 56-60 ℃, the extraction amount is controlled by adjusting the opening degree of a valve for heating steam, the micro-positive pressure in the tower is achieved, the pressure difference between the tower kettle and the top of the tower is 6-8Kpa, the temperature of the tower kettle is 70-80 ℃, and the process control key point is that the acetone content in the tower kettle is less than or equal to 5%. The acetone content in the material extracted from the tower top can reach more than 90 percent and is completely returned to the condensation reaction process to be used as the raw material. The discharge content of the kettle liquid is 2 percent of acetone, 24.4 percent of mesitylene, 3.69 percent of mesitylene, 3.47 percent of diacetone alcohol, 50.07 percent of isophorone, 8.59 percent of recombinant component and 7.78 percent of others.
And step three, reducing pressure and removing lightness: the process is carried out in a reduced pressure rectifying tower, in order to reduce the volatilization of light components such as acetone and the like, the vacuum degree of the rectifying tower is controlled to be-0.05-0.06 Mpa, the tower top temperature is 56-80 ℃, the tower kettle temperature is 70-100 ℃, the pressure difference is 6-8Kpa, and the process is controlled to have the key point that the acetone content in the tower kettle is not more than 1%. The acetone content in the material extracted from the tower top can reach 80-85%, and the material is returned to the condensation reaction process and used as raw material. The discharge content of the kettle liquid is 0.6 percent of acetone, 24.76 percent of mesitylene, 3.74 percent of mesitylene, 3.52 percent of diacetone alcohol, 50.78 percent of isophorone, 8.71 percent of heavy components and 7.89 percent of the rest.
The weight removal process comprises the following steps: the material after light component removal enters a heavy component removal tower under the vacuum condition of-0.085 Mpa, the temperature of the tower kettle is 190 ℃ and the temperature of the tower top is 110 ℃ and 130 ℃, and the differential pressure is 2-3Kpa, and the control key point of the process is that the total content of the heavy components of the produced liquid at the tower top is not higher than 2 percent. The contents of the materials extracted from the top of the tower are 0.64 percent of acetone, 26.57 percent of mesitylene, 4.01 percent of mesitylene, 3.8 percent of diacetone alcohol, 54.51 percent of isophorone, 2 percent of heavy components and 8.47 percent of others. The tower bottom is mainly used for treating residues and tar as solid waste.
Removing impurities: the function of the impurity removing tower is to realize the primary separation of materials of each component, four different fractions are obtained, namely a front fraction, a crude mesitylene product, a crude isophorone product and a back fraction (kettle residue), the process is carried out in one clearance rectifying tower, and the separation of the multiple components is realized according to the parameters of different regulating towers of the fractions.
(1) The front fraction collection process comprises the following steps: under the conditions of kettle temperature not higher than 120 deg.C, top temperature 90-100 deg.C, vacuum degree-0.09 Mpa and pressure difference 6-8Kpa, the fraction containing mesitylene as main component is extracted, and the contents of said fraction are acetone 2.08%, mesitylene 82.02%, diacetone alcohol 12.34%, mesitylene 0.78% and other components 2.78%. The front cut fraction can be used as raw material for extracting the mesityl oxide or directly used as a composite organic solvent.
(2) The collection process of mesitylene fraction: under the conditions of the kettle temperature of 120-125 ℃, the top temperature of 100-105 ℃, the vacuum degree of-0.095 Mpa and the pressure difference of 6-8Kpa, the fraction with the main component of mesitylene is extracted, and the contents of the fraction are 12.05 percent of mesitylene, 54.37 percent of mesitylene, 8.13 percent of isophorone and 25.45 percent of the rest. The mesitylene in the component reaches more than 50 percent, further purification conditions are provided, and the fraction is completely fed into a mesitylene crude product tank and then rectified and purified to obtain a mesitylene finished product.
(3) Collecting a crude isophorone fraction: under the conditions of the kettle temperature of 130-150 ℃, the top temperature of 110-120 ℃, the vacuum degree of-0.098 Mpa and the pressure difference of 6-8Kpa, a fraction with the main component of isophorone is extracted, the content of the fraction is 0.97% of mesitylene, 0.29% of isophorone 93.72%, 0.37% of heavy components and 4.65% of other components, the fraction is used as a raw material for obtaining an isophorone finished product through next purification, and the further purification process of the fraction is out of the specification and the range of the patent.
(4) And (3) post-fraction: after the front fraction, the mesitylene fraction and the isophorone crude fraction are respectively purified, the residue with the total amount of about 5-8% remained in the bottom of the rear tower is also called bottom residue, and the main components of the residue are isophorone 34.38%, heavy components 22.77% and the other 42.85%. Although the content of the isophorone in the fraction is high, the conventional rectification process is difficult to further separate, because the flowability of the still residue is rapidly deteriorated due to the content of the isophorone which is further compressed, so that the after fraction/still residue is difficult to discharge from the rectification tower, and the normal operation of the rectification tower is influenced.
Rectifying and purifying mesitylene: delivering the mesitylene in the crude product tank into a rectifying tower, and extracting the mesitylene with the content higher than 98 percent by adjusting the reflux ratio under the conditions of the kettle temperature of 120-130 ℃, the top temperature of 105-110 ℃, the vacuum degree of-0.098 Mpa and the pressure difference of 6-8Kpa to obtain a mesitylene finished product.
The above description is only for the embodiments of the present invention, and it is obvious to those skilled in the art that various changes and modifications can be made without departing from the inventive concept of the present invention, and these changes and modifications are all within the scope of the present invention.
Claims (8)
1. A process for the purification of a cleavage by-product in a condensation reaction, comprising the preparation of an organic fraction: washing a product generated in the process of preparing 3, 5-dimethylphenol from isophorone to obtain a washed organic phase, performing weight removal treatment on the washed organic phase in a weight removal tower to obtain a weight removal organic phase, performing weight removal treatment on the weight removal organic phase in a light removal tower to obtain a light removal kettle liquid and a light removal front fraction for refining 3, 5-dimethylphenol, and washing an organic phase generated by the reaction of a 5% NaOH solution and the light removal front fraction to obtain an organic fraction; purification in the condensation reaction: carrying out Michael addition and elimination reaction on the organic fraction, acetone, process water and a catalyst in a reactor to generate isophorone, carrying out first-step heat source-free lightness removing treatment on a reacted mixture in an atmospheric distillation tower to obtain a first-step lightness removing product, continuously carrying out second-step atmospheric lightness removing treatment on the first-step lightness removing product in the atmospheric distillation tower to obtain a second-step lightness removing kettle liquid, carrying out third-step reduced lightness removing treatment on the second-step lightness removing kettle liquid in a reduced pressure rectification tower to obtain a third-step lightness removing kettle liquid, carrying out weight removing treatment on the third-step lightness removing kettle liquid in a weight removing tower to obtain a weight removing extracted liquid, carrying out the weight removing extracted liquid in a impurity removing tower, carrying out impurity removing treatment on the weight removing extracted liquid in the impurity removing tower, collecting impurity removing front fraction under the conditions that the kettle temperature is not higher than 120 ℃, the top temperature is 90-100 ℃, the vacuum degree is-0.09 MPa and the pressure difference is 6-8KPa, the fraction with main component of mesitylene is extracted as raw material for extracting mesitylene or directly used as compound organic solvent under the conditions of kettle temperature of 120-125 ℃, top temperature of 100-105 ℃, vacuum degree of-0.095 MPa and differential pressure of 6-8KPa, the fraction with main component of isophorone is extracted under the conditions of kettle temperature of 130-150 ℃, top temperature of 110-120 ℃, vacuum degree of-0.098 MPa and differential pressure of 6-8KPa,
the organic fraction does not contain phenolic substances, is liquid at normal temperature, and comprises 32-34% of mesitylene, 48-51% of mesitylene and 15-20% of other components by mass percent, wherein the other components comprise 8-11% of acetone, 3-4% of diacetone alcohol, 2% of water and 2-3% of other components.
2. The process for purifying the cracking by-product in the condensation reaction according to claim 1, wherein the overhead product of the atmospheric pressure lightness-removing in the second step is used as the raw material of the condensation reaction, and the overhead product of the reduced pressure lightness-removing in the third step is used as the raw material of the condensation reaction.
3. The process of claim 1, wherein mesityl oxide is added during the production of isophorone.
4. The process for purifying the cracking by-product in the condensation reaction as claimed in claim 1, wherein the flow ratio of acetone to the organic fraction is 9: 1-8: 1, the feed flow of the process water is controlled by the make-up water flow according to 15-20% of the total mass flow, the catalyst is 30% KOH solution, the amount of the catalyst is 0.1% of the total mass flow, the reaction temperature is 180-185 ℃, the reaction pressure is 1.8-2.2MPa, and the retention time is 30-45 min.
5. The process for purifying the cracking by-product in the condensation reaction as claimed in claim 1, wherein the first step of the heat-source-free light removal of the reaction solution is carried out by using the reaction heat of 180-185 ℃, the first step of the heat-source-free light removal is carried out in an atmospheric distillation tower, the temperature of the kettle is 120-130 ℃, the top temperature is 55-57 ℃, the removed products are mainly acetone and water, wherein the acetone is 95-98%, and the acetone is completely returned to the condensation reaction process to be used as the raw material.
6. The process for purifying the cracking by-product in the condensation reaction according to claim 1, wherein the second atmospheric light removal is continuously performed in an atmospheric distillation tower, the temperature of the top of the tower is controlled to be 56-60 ℃, the extraction amount is controlled by adjusting the opening degree of a valve for heating steam, the micro positive pressure in the tower is achieved, the pressure difference between the bottom of the tower and the top of the tower is 6-8KPa, the temperature of the bottom of the tower is 70-80 ℃, the content of acetone in the bottom of the tower is controlled to be less than or equal to 5%, and the content of acetone in the material extracted from the top of the tower can reach more than 90% and is completely returned to the condensation reaction process to be used as a raw material.
7. The process for purifying the cracking by-product in the condensation reaction according to claim 1, wherein the third step of the pressure reduction and light component removal is carried out in a pressure reduction rectifying tower, the vacuum degree of the pressure reduction rectifying tower is controlled to be-0.05 to-0.06 MPa, the temperature at the top of the tower is controlled to be 56 to 80 ℃, the temperature at the bottom of the tower is controlled to be 70 to 100 ℃, the pressure difference is controlled to be 6 to 8KPa, the content of acetone in the bottom of the tower is controlled to be less than or equal to 1%, and the content of acetone in the material extracted from the top of the tower can reach 80 to 85%, and the material is completely returned to the condensation reaction process to be used as a raw material.
8. The process for the purification of cracking byproducts in condensation reactions as claimed in claim 1, wherein the rectification purification of mesitylene: delivering the mesitylene in the crude product tank into a rectifying tower, and extracting the mesitylene with the content higher than 98 percent by adjusting the reflux ratio under the conditions of the kettle temperature of 120-130 ℃, the top temperature of 105-110 ℃, the vacuum degree of-0.098 MPa and the pressure difference of 6-8KPa to obtain a mesitylene finished product.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50160240A (en) * | 1974-05-15 | 1975-12-25 | ||
| US5352839A (en) * | 1993-09-09 | 1994-10-04 | Aristech Chemical Corporation | Isophorone process |
| CN103435461A (en) * | 2013-07-24 | 2013-12-11 | 河北工业大学 | Production technology for isophorone |
| CN104355969A (en) * | 2014-10-16 | 2015-02-18 | 荣成青木高新材料有限公司 | Preparation method of 3, 5-dimethylphenol |
| CN107573227A (en) * | 2017-08-30 | 2018-01-12 | 中国石油大学(华东) | Acetone vapour phase condensation prepares the device and method of isophorone |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50160240A (en) * | 1974-05-15 | 1975-12-25 | ||
| US5352839A (en) * | 1993-09-09 | 1994-10-04 | Aristech Chemical Corporation | Isophorone process |
| CN103435461A (en) * | 2013-07-24 | 2013-12-11 | 河北工业大学 | Production technology for isophorone |
| CN104355969A (en) * | 2014-10-16 | 2015-02-18 | 荣成青木高新材料有限公司 | Preparation method of 3, 5-dimethylphenol |
| CN107573227A (en) * | 2017-08-30 | 2018-01-12 | 中国石油大学(华东) | Acetone vapour phase condensation prepares the device and method of isophorone |
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