CN105194998A - Treatment method for tail gas in benzophenone preparation - Google Patents
Treatment method for tail gas in benzophenone preparation Download PDFInfo
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- CN105194998A CN105194998A CN201510619976.1A CN201510619976A CN105194998A CN 105194998 A CN105194998 A CN 105194998A CN 201510619976 A CN201510619976 A CN 201510619976A CN 105194998 A CN105194998 A CN 105194998A
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- tail gas
- absorption tower
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Abstract
The invention discloses a treatment method for tail gas in benzophenone preparation. The treatment method includes A, injecting the tail gas from the bottom of a primary absorption tower upwardly, and absorbing hydrogen chloride by spraying water at the top of the primary absorption tower; B, injecting the tail gas subjected to absorption in the step A from the bottom of a secondary absorption tower upwardly, and absorbing the hydrogen chloride by spraying water at the top of the secondary absorption tower again; C, injecting the tail gas subjected to absorption in the step B from the bottom of a tertiary absorption tower upwardly, and absorbing the hydrogen chloride by spraying water at the top of the tertiary absorption tower for the third time; D, injecting the tail gas subjected to absorption in the step C into a purifying tower full of phosgene absorbing catalysts; E, enabling the tail gas subjected to decomposition and absorption in the step D to enter an alkali neutralization container full of a sodium hydroxide solution, and completing treatment. The treatment method for the tail gas in benzophenone preparation is low in cost and high in environmental friendliness.
Description
Technical field
The present invention relates to chemical field, be specifically related to a kind of processing method preparing tail gas in benzophenone.
Background technology
Benzophenone is white glossiness prismatic crystallization.Resembling rose, sweet taste, 1G is dissolved in 7.5ml ethanol, 6ml ether, is dissolved in chloroform, water insoluble, relative density (d504) 1.0869, fusing point 48.5 DEG C, boiling point 305.4 DEG C, index of refraction (n45.2D) 1.5975, flash-point 138 DEG C, irritant.Molecular formula: C
13h
10o, structural formula
; Molecular weight: 182; Physical and chemical performance: proportion: 1.098(g/cm
3, 20 DEG C), boiling point: 306 DEG C, water insoluble, is dissolved in many organic solvents such as ethanol, benzene, chloroform.Purposes: ultra-violet absorber, organic synthesis raw material and medicine intermediate, spices fixastive.
Existing benzophenone synthetic route has phosgenation, chlorobenzoyl chloride method, carbon dioxide process, carbon monoxide method, benzoic acid (or benzoyl oxide) method, carbon tetrachloride method, catalytic oxidation, decarboxylation method etc.Wherein phosgenation is with phosgene and benzene for raw material, take lewis acid as catalyst, carries out Friedel-Crafts reaction, through hydrolysis, layered shaping, refining etc. prepares benzophenone.It is high that the method has product quality, and reaction yield is higher, and process conditions are gentle, do not need by advantages such as special reagent and raw material are easy to get.The raw material that existing phosgenation prepares phosgene is mainly alchlor, benzene photoreactive gas, obtains through photochemical, hydrolysis, alkali cleaning, water-benzene distillation, distillation; Photochemical: to get alchlor 1 part and 1 part of phosgene is photochemical in photochemical still; Hydrolysis: in temperature less than 30 DEG C hydrolysis; Alkali cleaning: add sodium carbonate alkali cleaning, obtains material phase; Water-benzene distillation: obtain crude product; Finished product is obtained again after distillation rectifying; Wherein the molecular formula of benzene is C
6h
6, structural formula
, molecular weight is 78; Physico-chemical property: density: 0.879(g/cm
320 DEG C), boiling point: 80.4 DEG C; Basic chemical raw materials, water insoluble, be dissolved in many organic solvents such as ethanol, ether, gasoline, under certain condition, in molecule, hydrogen is replaced and produce halogenation, sulfonating reaction, and also can play addition reaction with chlorine, benzene is inflammable, explosive material; Explosion limit: mix 1.5 ~ 8%(volume ratio with air).
Aluminum trichloride (anhydrous) molecular formula: AlCl
3, molecular weight: 133.5, physico-chemical property: density 2.41(g/cm
320 DEG C) solubility: 69.9(g/100gH
2o20 DEG C) water-soluble, generate AlCl
36H
2o, also can be dissolved in ethanol, ether, releases large calorimetric, AlCl during dissolving
3there is strong adduction, generate dimeric molecule (AlCl
3)
2, the catalyst that alchlor can do organic synthesis also can be used for process lubricating oil and manufactures anthraquinone etc.; Outward appearance: the particle of faint yellow, yellow or grayish or powder, do not have and be greater than the block of 10mm.
The molecular formula of phosgene is COCl
2; Structural formula is
, molecular weight is 98.92, physical and chemical performance:
Proportion D
, 1.441, boiling point is 8.2 DEG C, is colourless gas, has rotten apple taste, have asphyxiating under normal temperature, belong to extremely toxic substance, aerial safe level is 0.5mg/m
3, phosgene is soluble in the organic solvent such as arsenic trichloride and glacial acetic acid, chloroform, toluene, chlorobenzene, water-soluble hardly; Be colourless gas under normal temperature, have rotten apple taste, have asphyxiating, belong to extremely toxic substance, aerial safe level is 0.5mg/m
3, phosgene is soluble in the organic solvent such as arsenic trichloride and glacial acetic acid, chloroform, toluene, chlorobenzene, water-soluble hardly.
Produce principle be: benzene under alchlor makes the condition of catalyst with phosgene generation acylation reaction; generate benzophenone-alchlor complex compound; namely obtain product through hydrolysis, alkali cleaning, distillation, sheeting, the mechanism of reaction and chemical equation are: (1) photochemical reaction: benzene generates benzophenone-alchlor complex compound with phosgene reaction under alchlor makes catalysts conditions:
。
(2) hydrolysis: benzophenone alchlor complex compound is met water decomposition and generated benzophenone:
。
The contingent side reaction of production process is that chlorobenzoyl chloride and alchlor reaction generate chlorobenzoyl chloride alchlor complex compound, meets water hydrolysis and generates the accessory substances such as benzoic acid, affect benzophenone product quality and yield.
。
In the process of producing, have hydrogen chloride gas produce, hydrogen chloride gas, be a kind of colourless non-combustible gas, have polar stimulation smell, proportion is greater than air, has corrosivity, and therefore, the tail gas of generation needs process.In addition, in the process of reaction, the incomplete phenomenon of phosgene reaction may be there is, and phosgene is poisonous, therefore, also needs unreacted phosgene process.During existing business processes, usually easy to operate object is in, directly discarded passing in alkaline solution is carried out neutralization reaction, although this kind of method of operating is simple and practical, the waste liquid produced after neutralization will could discharge usually after treatment, surface is seen simple to operate and practical, but in fact, add processing cost, and the feature of environmental protection is poor.
Summary of the invention
The technical problem to be solved in the present invention is to provide the low and processing method for the preparation of tail gas in benzophenone that the feature of environmental protection is good of a kind of cost.
In order to solve the problems of the technologies described above, the invention provides following technical scheme: the processing method preparing tail gas in benzophenone, its method of operating is as follows:
A, the bottom of tail gas from first grade absorption tower upwards to be passed into, meanwhile, the top spray water absorbing hydrogen chloride gas of first grade absorption tower;
B, through steps A absorb after tail gas upwards pass into from the bottom of two-level absorption tower, meanwhile, the top spray water absorbing hydrogen chloride gas again of two-level absorption tower;
C, tail gas after step B absorbs upwards pass into from the bottom on three grades of absorption towers, meanwhile, and the top spray water on three grades of absorption towers third time absorbing hydrogen chloride gas;
D, through step C absorb after tail gas enter the purifying column being full of phosgene absorbing catalyst;
E, through step D decompose absorb after tail gas enter in alkali and in container, have sodium hydroxide solution in alkali He in container, be disposed.
Adopt the processing method preparing tail gas in benzophenone of technical solution of the present invention, through first grade absorption tower, two-level absorption tower, three grades of absorption towers, hydrogen chloride gas water is absorbed, during absorption, gas passes into from bottom to top, water is from top spray, make water and hydrogen chloride gas fully contact and absorb, hydrogen chloride gas enters in water can become hydrochloric acid, can process industrial utilization.Purifying column is used for phosgene to absorb process by phosgene absorbing catalyst.Last again by the remaining tail gas of alkali neutralisation treatment, in the process of practical operation, tail gas through and absorption tower, two-level absorption tower, three grades of absorption towers and purifying column process after, substantially exist without residual gas, but for the purpose of environmental protection, increase alkali neutralization procedure, ensure emission-free escaping in external environment.
The present invention is compared with the existing mode of operation only having alkali to neutralize, and hydrogen chloride gas first absorbs after process through water, generates hydrochloric acid, recyclable industrial utilization; Through purifying column, phosgene is absorbed again, finally use in alkali and ensure security.Simple to operate, the liquid of last alkali neutralization is not substantially containing tail gas, and therefore, repeatedly can utilize, and without the need to discharging, comparatively speaking, decrease the process disposed waste liquid, cost reduces, and the feature of environmental protection is good.
Further, the shower water on described first grade absorption tower, two-level absorption tower, three grades of absorption towers is all in the shape of a spiral from overhead stream to bottom; Described tail gas is upwards overflowed in the shape of a spiral from the bottom on first grade absorption tower, two-level absorption tower, three grades of absorption towers, and the spiral flow of shower water overlaps to the spiral of tail gas track of overflowing.Shower water and tail gas combine all in the shape of a spiral, and make the path in first grade absorption tower, two-level absorption tower, three grades of absorption towers longer, time of contact is longer, is convenient to the absorption of hydrogen chloride gas.
Further, the place of bottom centre on described first grade absorption tower, two-level absorption tower and three grades of absorption towers is provided with air pump.Air pump will be evacuated to bottom by air pump by escaping gas in the shape of a spiral again, again circulate and will overflow in the shape of a spiral, again absorb, hydrogen chloride gas be absorbed more.
Further, circulation of tail gas flowing in described purifying column, phosgene absorbing catalyst is that shape spray ejection contacts with tail gas.Circulation of tail gas flowing sprays with shape spray phosgene absorbing catalyst, makes the contact area of tail gas and catalyst larger, makes absorption more complete.
Further, described purifying column is divided into purification bottom, purification middle level and purification upper strata, is equipped with the screen cloth with switch between purification bottom and purification middle level, between purification middle level and purification upper strata.Purification bottom is when screen cloth is closed, make gas in the circulation of purification bottom, increase its absorptivity, and then open the switch of screen cloth, make tail gas escape into purification middle level, again absorb, finally open screen cloth switch, make tail gas escape into purification upper strata, finally absorb, three grades of absorptions, make absorption more complete.
Further, the top place of described screen cloth is provided with the cover plate of the mesh that to be crisscross arranged with screen cloth mesh, and cover plate and screen cloth are rotationally connected.The mesh of cover plate and the mesh of screen cloth interlock, and only need rotating plate, and casing realizes the effect of opening, closing screen cloth mesh.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of device therefor in the embodiment of the present invention.
In figure: first grade absorption tower 1, two-level absorption tower 2, three grades of absorption towers 3, helical pipe 4, shower water 5, air pump 6, purifying column 7, purification bottom 8, purification middle level 9, purification upper strata 10, screen cloth 11, cover plate 12, in alkali and container 13.
Detailed description of the invention
As shown in Figure 1, the present invention prepares the processing method of tail gas in benzophenone, and its method of operating is as follows:
A, first grade absorption tower 1 is in tubular, helical pipe 4 is provided with in tubular, helical pipe 4 extends to top by bottom, but there is gas egress passages between the top of helical pipe 4 top and first grade absorption tower 1, place of bottom centre is provided with air pump 6, water from the top spray of first grade absorption tower 1 to, tail gas is upwards passed into bottom the helical pipe 4 of first grade absorption tower 1, simultaneously, the top spray water 5 absorbing hydrogen chloride gas of first grade absorption tower 1, absorbed in the process that gas is upwards overflowed, then overflow from top, again be evacuated to bottom by air pump 6, recirculation is upwards overflowed, then air pump 6 is closed,
B, gas then escape into two-level absorption tower 2 from first grade absorption tower 1, the bottom of two-level absorption tower 2 is connected with the top seal of first grade absorption tower 1 and communicates, the structure of two-level absorption tower 2 is consistent with first grade absorption tower 1, tail gas after steps A absorbs upwards passes into from the bottom of two-level absorption tower 2, simultaneously, the top spray water 5 absorbing hydrogen chloride gas again of two-level absorption tower 2, absorbed in the process that gas is upwards overflowed, then overflow from top, again be evacuated to bottom by air pump 6, recirculation is upwards overflowed, and then closes air pump 6;
C, gas then escape into three grades of absorption towers 3 from two-level absorption tower 2, the bottom on three grades of absorption towers 3 is connected with the top seal of two-level absorption tower 2 and communicates, the structure on three grades of absorption towers 3 is consistent with first grade absorption tower 1, tail gas after step B absorbs upwards passes into from the bottom on three grades of absorption towers 3, simultaneously, the top spray water 5 third time absorbing hydrogen chloride gas on three grades of absorption towers 3, absorbed in the process that gas is upwards overflowed, then overflow from top, again be evacuated to bottom by air pump 6, recirculation is upwards overflowed, and then closes air pump 6;
D, gas enters in purifying column 7 through three grades of absorption towers 3, the bottom of purifying column 7 is connected with the top seal on three grades of absorption towers 3 and communicates, purifying column 7 is tubular, and purification bottom 8 is divided into from the bottom of cylinder to top, purification middle level 9 and purification upper strata 10, between purification bottom 8 and purification middle level 9, be equipped with screen cloth 11 between purification middle level 9 and purification upper strata 10, screen cloth 11 is provided with the cover plate 12 of the mesh that to be crisscross arranged with screen cloth 11 mesh, first rotation cover 12, close the screen cloth 11 between purification bottom 8 and purification middle level 9, gas enters to purification bottom 8, then circulate, phosgene absorbing catalyst is active carbon, then sprayed by shower nozzle circulation at purification bottom 8, after reaction a period of time, rotation cover 12, open screen cloth 11, gas escapes into purification middle level 9, simultaneously, close the screen cloth 11 between purification middle level 9 and purification upper strata 10, in purification middle level 9 after reaction, identical operation, gas escapes into purification upper strata 10 again and continues reaction, after having reacted, tail gas is passed in alkali with in container 13,
Be provided with tube connector in E, alkali and between the top of container 13 and purifying column 7, gas is overflowed through tube connector, and passes into in container 13 in alkali, and be placed with sodium hydroxide solution in alkali He in container 13, remaining tail gas and NaOH react and neutralizes, and process completes.
Repeat the method for operating of 50 embodiment of the present invention, measure after each step completes, the average residual content of hydrogen chloride gas photoreactive gas, as follows:
Hydrogen chloride content in untreated front waste gas is 80%, and phosgene is 20%;
After first grade absorption tower 1: hydrogen chloride content 62.5%; Phosgene content 18.3%;
After two-level absorption tower 2: hydrogen chloride content 36.2%; Phosgene content 17.1%;
Behind three grades of absorption towers 3: hydrogen chloride content 0.8%; Phosgene content 15.9%;
After purifying column 7: hydrogen chloride content 0.8%; Phosgene content 0.22%;
With rear in alkali: hydrogen chloride content 0; Phosgene content 0.
As can be seen here, by safety and environmental protection in the tail gas after disposal methods of the present invention.
For a person skilled in the art, under the prerequisite not departing from structure of the present invention, can also make some distortion and improvement, these also should be considered as protection scope of the present invention, and these all can not affect effect of the invention process and practical applicability.
Claims (6)
1. prepare the processing method of tail gas in benzophenone, it is characterized in that: its method of operating is as follows:
A, the bottom of tail gas from first grade absorption tower upwards to be passed into, meanwhile, the top spray water absorbing hydrogen chloride gas of first grade absorption tower;
B, through steps A absorb after tail gas upwards pass into from the bottom of two-level absorption tower, meanwhile, the top spray water absorbing hydrogen chloride gas again of two-level absorption tower;
C, tail gas after step B absorbs upwards pass into from the bottom on three grades of absorption towers, meanwhile, and the top spray water on three grades of absorption towers third time absorbing hydrogen chloride gas;
D, through step C absorb after tail gas enter the purifying column being full of phosgene absorbing catalyst;
E, through step D decompose absorb after tail gas enter in alkali and in container, have sodium hydroxide solution in alkali He in container, be disposed.
2. the processing method preparing tail gas in benzophenone according to claim 1, is characterized in that: the shower water on described first grade absorption tower, two-level absorption tower, three grades of absorption towers is all in the shape of a spiral from overhead stream to bottom; Described tail gas is upwards overflowed in the shape of a spiral from the bottom on first grade absorption tower, two-level absorption tower, three grades of absorption towers, and the spiral flow of shower water overlaps to the spiral of tail gas track of overflowing.
3. the processing method preparing tail gas in benzophenone according to claim 2, is characterized in that: the place of bottom centre on described first grade absorption tower, two-level absorption tower and three grades of absorption towers is provided with air pump.
4. the processing method preparing tail gas in benzophenone according to claim 3, is characterized in that: circulation of tail gas flowing in described purifying column, and phosgene absorbing catalyst is that shape spray ejection contacts with tail gas.
5. the processing method preparing tail gas in benzophenone according to claim 4, it is characterized in that: described purifying column is divided into purification bottom, purification middle level and purification upper strata, between purification bottom and purification middle level, between purification middle level and purification upper strata, be equipped with the screen cloth with switch.
6. the processing method preparing tail gas in benzophenone according to claim 5, is characterized in that: the cover plate being provided with the mesh that to be crisscross arranged with screen cloth mesh of described screen cloth, and cover plate and screen cloth are rotationally connected.
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| CN201510619976.1A CN105194998A (en) | 2015-09-25 | 2015-09-25 | Treatment method for tail gas in benzophenone preparation |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109663477A (en) * | 2018-12-30 | 2019-04-23 | 安徽广信农化股份有限公司 | A kind of method for treatment of waste material preparing ethyl chloroformate |
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2015
- 2015-09-25 CN CN201510619976.1A patent/CN105194998A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109663477A (en) * | 2018-12-30 | 2019-04-23 | 安徽广信农化股份有限公司 | A kind of method for treatment of waste material preparing ethyl chloroformate |
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| PB01 | Publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20151230 |
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| WD01 | Invention patent application deemed withdrawn after publication |