CN106928172A - A kind of process for refining of dibenzofuran - Google Patents

Abstract

The present invention relates to a kind of process for refining of dibenzofuran, as raw material, direct crystallisation by cooling centrifugation obtains the thick dibenzofuran containing dibenzofuran 85% or so to the dibenzofuran cut containing dibenzofuran 55%~65% that it is obtained with washing oil Residual oil or heavy wash oil rectifying, and thick dibenzofuran adds 95% ethanol and DMF（N, N dimethylformamide）Mixed solvent rising temperature for dissolving, a certain amount of water is then added dropwise and separates out impurity fluorenes as precipitating reagent, solution crystallisation by cooling after heat filtering, be centrifugally separating to obtain dibenzofuran of the content more than 98%, yield is more than 85%.Mixed solvent and precipitating reagent, two-step method refine dibenzofuran, it is to avoid secondary rectifying, reduce energy consumption, the whole technique is had the multiple advantages such as simple to operate, good product quality, product yield high, solvent load is few, safety and environmental protection.

Description

A kind of process for refining of dibenzofuran

Technical field

Dibenzofuran in the present invention is coal tar deep processing product, belongs to chemical technology field, particularly a kind of from coal tar In refine dibenzofuran technique.

Background technology

Contain dibenzofuran 1%~2%, the category component that content is higher, purposes is larger in coal tar.Dibenzofuran can be used as heat carrier and food Product and the preservation of timber against decay agent etc..Its deep processing product, such as dibenzofuran 2,3- acid can be used to produce dyestuff, 3- aminoalkyl dibenzofuran Can be used as convulsion relieving agent and anodyne, chlorination dibenzofuran can be used as the additive of electrically insulating material, and sulfonated polycondensate can be used as weaving Auxiliary agent and wetting agent etc..

Separation and refining method on dibenzofuran is write in Wang Zhaoxiong, Gao Jinsheng etc.《The refined and utilization of coke chemicals》One That is introduced in book is more detailed（P313~315）, dibenzofuran long distillate is cut by rectifying of raw material of heavy wash oil（Dibenzofuran content 55%~65%）, secondary rectifying cuts narrow fraction（Dibenzofuran content 80.8%）, then make solvent crystallisation by cooling with alpha-methyl-naphthalene and obtain Dibenzofuran product of the content more than 95%.Have many advantages, such as solvent with alpha-methyl-naphthalene, but still suffer from two problems, one is to solvent Alpha-methyl-naphthalene requires height in itself, and alpha-methyl-naphthalene content is more than 80%, and beta-methylnaphthalene is more few better due to crystalline temperature high content, and Alpha-methyl-naphthalene and beta-methylnaphthalene boiling point only differ 3.5 DEG C, and intersolubility is again especially good, so either rectification method or crystallisation will Obtain that the little alpha-methyl-naphthalene cut of beta-methylnaphthalene content is extremely difficult, cost is very high, economically infeasible；Two is alpha-methyl-naphthalene Cut is poor to the removal ability of impurity fluorenes, it requires that dibenzofuran narrow fraction does not allow fluorenes to be mixed into as far as possible, and the impurity of dibenzofuran is main just It is acenaphthene and fluorenes, does not allow fluorenes to be mixed into extremely difficult, reflux ratio that will be very big during rectifying, such energy consumption can be very high, while in cutting oxygen Fluorenes one occurs that other cuts will be changed to during fluorenes narrow fraction, and at this moment dibenzofuran content is also very high, and this can largely have lost The yield of dibenzofuran.Another method is that, dibenzofuran narrow fraction crystallisation by cooling, centrifugal filtration obtains thick dibenzofuran, then tied again with alcohol Crystalline substance obtains dibenzofuran product twice, and thick dibenzofuran and Alcohol by weight compare 1: 1.5~2.The problem of this method is that rectifying twice could be obtained To narrow fraction, high energy consumption；Alcohol is poor to the solvability of dibenzofuran, and solvent consumption is big；Alcohol is very poor to the solvability of impurity fluorenes, The fluorenes content in strict limitation dibenzofuran narrow fraction is needed, difficulty is big when so secondary rectifying obtains narrow fraction, high energy consumption, yield are low. Institutes Of Technology Of Taiyuan's beam knows strong Master's thesis《The extraction of fluorenes and dibenzofuran in washing oil》In be also use alpha-methyl-naphthalene cut make molten Agent is crystallized, and equally exists problem above.

The B propositions of patent CN 102731282 carry out the side of supercritical extract dibenzofuran with methyl alcohol, ethanol and toluene as solvent Method, the quality and yield of product is all fine, but supercritical extract needs high temperature（235℃）And high pressure（7MPa）, equipment requirement is high, Investment is big, and industrialized production is not appropriate at present.The A of patent CN 102898269 are also to be carried out by extractant of Supercritical Ethanol Supercritical extract, acenaphthene, fluorenes and the dibenzofuran of high concentration are obtained through cooling system cooling, it is last it is purified, crystallize, be filtrated to get it is high-purity The finished product of degree, equally exists the problem that equipment requirement is high, investment is big, be not suitable for industrialized production at present.

The A of patent CN 103012341, disclose a kind of method of industrial continuous production high-purity technical dibenzofuran.It with Heavy wash oil is raw material, first prepares the dibenzofuran cut that fluorenes content is less than 1% and dibenzofuran content is 70%~75%, then made with n-butanol Dibenzofuran cut solvent, by once recrystallizing, obtains industrial dibenzofuran product of the purity more than 96%.Dibenzofuran and fluorenes boiling point difference are only There are 10 DEG C, to prepare fluorenes content less than 1% and dibenzofuran content is substantially exactly to obtain above-mentioned in 70%~75% dibenzofuran cut Dibenzofuran narrow fraction is, it is necessary to big reflux ratio, high energy consumption, yield are low.

Technique of the invention is exactly the refined work of a kind of new dibenzofuran developed on the basis of above technology advantage and disadvantage are summarized Skill, this technique with the dibenzofuran cut containing dibenzofuran 55%~65% be raw material, without limit dibenzofuran cut in impurity fluorenes content and The content of acenaphthene, with raw material obtain easily, few, simple to operate equipment investment, good product quality, product yield be high, solvent load Less, the multiple advantages such as safety and environmental protection.

The content of the invention

The purpose of the present invention aims to provide a kind of process for refining of dibenzofuran, and it is with the dibenzofuran cut containing dibenzofuran 55%~65% Raw material, is obtained after thick dibenzofuran, solvent dissolve by cut crystallisation by cooling and goes removal of impurity fluorenes and recrystallization to go removal of impurities with precipitating reagent water Matter acenaphthene obtains dibenzofuran of the content more than 98%, and yield is 85% or so.This technique have raw material obtain easily, equipment investment it is few, behaviour Make the multiple advantages such as simple, good product quality, product yield high, solvent load is few, safety and environmental protection.

Technical scheme is comprised the steps of, and its process flow diagram is shown in Fig. 1：

Step 1：Added in the crystallizer with stirring after dibenzofuran cut containing dibenzofuran 55%~65% is heated into 90 DEG C of dissolvings, control Mixing speed processed is 15r/min~20r/min, and material then is dropped into 20 DEG C~25 DEG C, centrifugation with the rate of temperature fall of 10 DEG C/h The thick dibenzofuran of content 85% or so is obtained after separation；

Step 2：In mass ratio it is 1 by thick dibenzofuran and mixed solvent containing dibenzofuran 85% or so:0.5 ratio is added with stirring Crystallizer in, 60 DEG C are warmed up under stirring condition and are completely dissolved, the water equivalent to solvent quality 20% under constant temperature stirring condition It is added dropwise into crystallizer, 30min is dripped off, then heat filtering, obtains filtrate and a small amount of filter cake, mixed solvent here is by 95% Ethanol and DMF（N,N-dimethylformamide）In mass ratio 4:1 ratio is mixed；

Step 3：Filtrate after step 2 heat filtering is extracted into another crystallizer and is dropped with the speed of 10 DEG C/h under agitation To 20 DEG C, centrifugation obtains the dibenzofuran product of filtrate and content more than 98% to temperature；

Step 4：It is used to produce Industrial fluorene after a small amount of filtration cakes torrefaction that step 2 is obtained；

Step 5：Step 3 is obtained into filtrate by solvent recovery kettle vacuum distillation recovered solvent, 5 meters of silk screens high is added on kettle and is filled out The rectifying column of material, controls tower top temperature to realize the initial gross separation of ethanol, water and DMF by flowing back, and ethanol and DMF press 4:1 ratio Example mixing circulation is utilized, and water is reused as dropwise addition with water, and the Residual oil after recycling design time is fitted on washing oil Residual oil or heavy is washed Continue to produce dibenzofuran cut in oil.

In coal tar wash oil, the front and rear component of dibenzofuran is respectively the thick dibenzofuran after acenaphthene and fluorenes, thus the crystallization of dibenzofuran cut In impurity be exactly mainly acenaphthene and fluorenes, obtain the dibenzofuran cut containing dibenzofuran 55%~65% and be easy to, but to obtain very low containing fluorenes Dibenzofuran narrow fraction is then very difficult, but because the general solubility in a solvent of fluorenes is lower than dibenzofuran, recrystallization cannot be removed, so existing There is technique to have to remove removal of impurity fluorenes by the way of rectifying obtains narrow fraction mostly, thus the production cycle is long, energy consumption is big, product Yield is low.Due to acenaphthene, dibenzofuran and fluorenes, the difference of solubility causes to add the priority separated out after water sedimentation agent suitable in the mixed solvent Sequence is different, and fluorenes is first separated out, and is separated out after dibenzofuran, and acenaphthene is not separated out, and using this principle, present invention process is targetedly from compound Solvent and precipitating reagent, take the operating procedure of two-step method, and first the impurity fluorenes removal for separating out, then crystallisation by cooling obtains dibenzofuran, Impurity acenaphthene has then been stayed in solution, so as to obtain high-quality and dibenzofuran product in high yield.

The technological improvement that the present invention is done mainly has at 2 points：One is the mixed solvent constituted from ethanol and DMF as thick The recrystallization solvent of dibenzofuran removes removal of impurity acenaphthene；Two is the impurity fluorenes for first removing indissoluble as precipitating reagent from water.This 2 points improvement The present invention is set to have the advantages that in process of production following prominent：

1. due to can first remove removal of impurity fluorenes, it is possible to make raw material from the dibenzofuran cut containing dibenzofuran 55%~65%, without logical Cross secondary rectifying to limit the content of impurity fluorenes, raw material obtains easy, and energy consumption is low, while the equipment for decreasing secondary rectifying is thrown Enter；

2. dibenzofuran cut can not removed during solubilizer direct crystallization obtains the thick dibenzofuran of 85% content except acenaphthene and fluorenes it Other outer impurity, make recrystallization process solvent consumption few, and product yield is high and safety and environmental protection；

3. adding appropriate DMF in ethanol can promote the dissolving of thick dibenzofuran, reduce the usage amount of recrystallization process solvent, while In turn ensure that the yield of dibenzofuran；

4. water is dissolved each other with ethanol and DMF, and the dissolving power of mixed solvent can be reduced after addition, thus is played a part of precipitating reagent and made The fluorenes of most indissoluble crystallizes precipitation first, and the amount and crystallization temperature of control addition water can ensure the quality and yield of dibenzofuran.

5. two-step method operation, a step heat filtering goes removal of impurity fluorenes, step recrystallization to remove removal of impurity acenaphthene, whole technological operation letter Single, flow is short.

6. solvent recovery kettle vacuum distillation recovered solvent and waste water, solvent mixing circulation utilization in proportion, waste water is used as drop Plus reused with water, whole process safety and environmental protection.

Brief description of the drawings

Fig. 1 is process flow diagram of the invention.

Specific embodiment

The present invention is further illustrated by the following examples：

Embodiment 1

As shown in figure 1, the dibenzofuran cut containing dibenzofuran 58.26% is heated to 90 DEG C of fusings in storage tank, volume is then added to for 8m3 Dibenzofuran crystallizer in, add 6000kg, 25 DEG C, then constant temperature 1h are at the uniform velocity cooled to the speed of 10 DEG C/h under agitation, Thick dibenzofuran 3770kg is centrifugally separating to obtain afterwards, and containing dibenzofuran 84.11%, the yield of this process is 90.71%.

The de- brilliant oil being centrifuged out is used to wash benzene in being blended into washing oil.

Thick dibenzofuran obtained above is added in the dibenzofuran crystallizer of volume 8m3 with strip machine, mixed solvent is added 1885kg（Mixed solvent is by 95% ethanol and DMF in mass ratio 4:1 ratio is mixed）, stirring be warmed up to 60 DEG C completely it is molten Solution, is added dropwise water 377kg under stirring condition, 30min is dripped off, it is impossible to drop it is too fast, lead in filter while hot, vacuum filtration, filter Liquid is directly pumped in another dibenzofuran crystallizer, and 20 DEG C, constant temperature 1h, afterwards centrifugation are at the uniform velocity cooled to the speed of 10 DEG C/h Dibenzofuran 3030kg is obtained, containing dibenzofuran 98.12%, the yield of this process is 93.76%, and total recovery is 85.05%.

Filter cake after vacuum filtration is used to produce Industrial fluorene.

Filtrate enters solvent recovery kettle rectification under vacuum recycling design, and 5 meters of rectifying columns of wire packing high are provided with kettle, passes through Flow back to control tower top temperature to realize the initial gross separation of ethanol, water and DMF, ethanol and DMF in mass ratio 4:1 mixing circulation profit With water is reused as dropwise addition with water, and the Residual oil after recycling design returns continuation in being fitted on washing oil Residual oil or heavy wash oil and produces Dibenzofuran cut.

Embodiment 2

Dibenzofuran cut 6000kg containing dibenzofuran 60.38% is added in dibenzofuran crystallizer, even with the speed of 10 DEG C/h under agitation Speed cools to 23 DEG C, then constant temperature 1h, and thick dibenzofuran 3860kg is centrifugally separating to obtain afterwards, containing dibenzofuran 85.26%, the receipts of this process Rate is 90.84%.

Thick dibenzofuran obtained above is added in dibenzofuran crystallizer with strip machine, mixed solvent 1930kg is added, stirring rises Temperature is completely dissolved to 60 DEG C, and dropwise addition water 386kg under stirring condition, 30min is dripped off, led in filter while hot, vacuum filtration, filter Liquid is extracted into another dibenzofuran crystallizer, and 20 DEG C are at the uniform velocity cooled to the speed of 10 DEG C/h, and constant temperature 1h is centrifugally separating to obtain dibenzofuran 3150kg, containing dibenzofuran 98.25%, the yield of this process is 94.04%, and total recovery is 85.43%.

Filtrate is entered the rectification under vacuum of solvent recovery kettle and reclaims two kinds of solvents and waste water, two kinds of solvents mixing circulation profit in proportion With waste water is reused as dropwise addition with water.

Embodiment 3

Dibenzofuran cut 6000kg containing dibenzofuran 62.56% is added in dibenzofuran crystallizer, even with the speed of 10 DEG C/h under agitation Speed cools to 20 DEG C, then constant temperature 1h, and thick dibenzofuran 3990kg is centrifugally separating to obtain afterwards, containing dibenzofuran 85.72%, the receipts of this process Rate is 91.12%.

Thick dibenzofuran obtained above is added in dibenzofuran crystallizer with strip machine, mixed solvent 1995kg is added, stirring rises To 60 DEG C, dropwise addition water 399kg under stirring condition, 30min is dripped off, led in filter while hot temperature, and vacuum filtration, filtrate is extracted into separately In one dibenzofuran crystallizer, 20 DEG C are at the uniform velocity cooled to the speed of 10 DEG C/h, constant temperature 1h is centrifugally separating to obtain dibenzofuran 3280kg, Containing dibenzofuran 98.56%, the yield of this process is 94.52%, and total recovery is 86.12%.

Filtrate is entered the rectification under vacuum of solvent recovery kettle and reclaims two kinds of solvents and waste water, two kinds of solvents mixing circulation profit in proportion With waste water is reused as dropwise addition with water.

Claims (1)

1. a kind of process for refining of dibenzofuran, it is characterised in that comprise the steps of：

Step 1：Added in the crystallizer with stirring after dibenzofuran cut containing dibenzofuran 55%~65% is heated into 90 DEG C of dissolvings, control Mixing speed processed is 15r/min~20r/min, and material then is dropped into 20 DEG C~25 DEG C, centrifugation with the rate of temperature fall of 10 DEG C/h The thick dibenzofuran of content 85% or so is obtained after separation；

Step 2：In mass ratio it is 1 by thick dibenzofuran and mixed solvent containing dibenzofuran 85% or so:0.5 ratio is added with stirring Crystallizer in, 60 DEG C are warmed up under stirring condition and are completely dissolved, the water equivalent to solvent quality 20% under constant temperature stirring condition It is added dropwise into crystallizer, 30min is dripped off, then heat filtering, obtains filtrate and a small amount of filter cake, mixed solvent here is by 95% Ethanol and DMF（N,N-dimethylformamide）In mass ratio 4:1 ratio is mixed；

Step 3：Filtrate after step 2 heat filtering is extracted into another crystallizer and is dropped with the speed of 10 DEG C/h under agitation To 20 DEG C, centrifugation obtains the dibenzofuran product of filtrate and content more than 98% to temperature；

Step 4：It is used to produce Industrial fluorene after a small amount of filtration cakes torrefaction that step 2 is obtained；

Step 5：Step 3 is obtained into filtrate by solvent recovery kettle vacuum distillation recovered solvent, 5 meters of silk screens high is added on kettle and is filled out The rectifying column of material, controls tower top temperature to realize the initial gross separation of ethanol, water and DMF by flowing back, and ethanol and DMF press 4:1 ratio Example mixing circulation is utilized, and water is reused as dropwise addition with water, and the Residual oil after recycling design time is fitted on washing oil Residual oil or heavy is washed Continue to produce dibenzofuran cut in oil.