CN103570519B - Synthetic method for preparing ketene by dehydrating acetic acid - Google Patents
Synthetic method for preparing ketene by dehydrating acetic acid Download PDFInfo
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- CN103570519B CN103570519B CN201310587988.1A CN201310587988A CN103570519B CN 103570519 B CN103570519 B CN 103570519B CN 201310587988 A CN201310587988 A CN 201310587988A CN 103570519 B CN103570519 B CN 103570519B
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- ketene
- acetic acid
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- tungstophosphoric acid
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/87—Preparation of ketenes or dimeric ketenes
- C07C45/89—Preparation of ketenes or dimeric ketenes from carboxylic acids, their anhydrides, esters or halides
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Abstract
The invention relates to a synthetic method for preparing ketene by dehydrating acetic acid. The method comprises the following specific steps: after being mixed by the mass ratio of 1: 0.03-0.001, acetic acid and an polymerization inhibitor are vaporized at 120-140 DEG C in an acetic acid evaporator, introduced to a fixed bed reactor after being pre-heated to be at 300-400 DEG C, and contacted with a catalyst to be subjected to a dehydration reaction for 3-10 seconds at 650-700 DEG C to generate ketene gas; after being cooled by 110-160 DEG C by a heat exchanger, the ketene gas is cooled and recycled by a brine cooler to obtain a ketene finished product. The synthetic method has the benefits of greatly improving the conversion rate and selectivity of the acetic acid as well as the yield of the ketene product, reducing the reaction temperature and the energy consumption, recycling heat energy and achieving the purposes of energy conservation and consumption reduction.
Description
Technical field
The present invention relates to the preparation method of the basic raw material of a kind of chemical field fine chemicals dyestuff, medicine, agricultural chemicals, food and feed additive, auxiliary agent etc., be specifically related to the synthesis technique that a kind of acetic acid dehydration prepares ketene.
Background technology
Ketene is the poisonous colourless gas of pungency, is slightly soluble in water, can be dissolved in multiple organic solvent.
Ketene is mainly used in chemical industry basic raw material and tube-nursery, is the main raw material producing food preservatives Sorbic Acid; Ketene is very unstable, and difficult storage, very easily form dipolymer ketene dimer, ketene dimer is the raw material of fine chemicals dyestuff, medicine, agricultural chemicals, food and feed additive, auxiliary agent etc.
Exemplary production method in current industrial production is: acetic acid is using triethyl phosphate, Secondary ammonium phosphate, phosphoric acid etc. as dehydration catalyst in high-temperature cracking furnace, and under 700-800 DEG C of high temperature, cracking generates ketene.Common process produces ketene, and acetic acid transformation efficiency can only reach 95%, selectivity lowlyer only has 90%, ketene yield also only has 85%.
Summary of the invention
Goal of the invention: the present invention, in order to overcome the defect of prior art, proposes a kind of effectively raising acetic acid transformation efficiency and ketene yield, simultaneously energy-saving and cost-reducing method.
For achieving the above object, the present invention adopts following technical scheme: be after the mixing of 1:0.03 ~ 0.001 in mass ratio by acetic acid and stopper, through acetate evaporator 120 ~ 140 DEG C vaporization, then after being preheated to 300 ~ 400 DEG C, fixed-bed reactor are entered, under 650 ~ 700 DEG C of conditions, with catalyst exposure generation dehydration reaction, generate ketene gas, be cooled to 110-160 DEG C through interchanger, then obtain ketene finished product through brine cooler cooling recovery.
Further preferably, described stopper is the one in sterically hindered phenol or amides in the present invention.Sterically hindered phenol is as pyrocatechol, 2,5-tert.-butyl phenols, 3,5-tertiary butyl-4-hydroxy phenylcarbinols; Amides RCONHR ', RCONR ' 2.Wherein R, R ', R ' 2 are carbonatomss is the saturated alkane of 0 ~ 3 or unsaturated alkane, as methane amide, ethanamide, dimethyl formamide, acrylamide etc.
Further preferably, described fixed-bed reactor are calandria type fixed bed reactor in the present invention.
Further preferably, the time of described dehydration reaction is 3-10S in the present invention.
Further preferably, described catalyzer is silicon dioxide carried tungstophosphoric acid in the present invention.Its preparation method is: tetraethoxy is dissolved in 6 ~ 15% ethanolic solns, and at 35 ~ 40 DEG C, hydrolysis obtains solution A; Tungstophosphoric acid is dissolved in dehydrated alcohol and obtains solution B, solution B is poured in solution A, 82 ~ 88 DEG C of reactions 4 ~ 6 hours, then by aqueous gel 40 ~ 45 DEG C of vacuum-dryings, finally by xerogel 140 ~ 160 DEG C of dried overnight, obtained tungstophosphoric acid content 10% ~ 40% silicon dioxide carried tungstophosphoric acid.
The present invention further preferably, the temperature of described brine cooler cooling Wei – 10～– 30 DEG C.
The invention has the advantages that: adopt silicon dioxide carried tungstophosphoric acid as catalyzer, adopt sterically hindered phenol, amides as stopper, and adopt the technique of calandria type fixed bed reactor, acetic acid transformation efficiency is made to reach 99%, selectivity reaches more than 96%, product ketene yield reaches more than 95%, original temperature of reaction 750 ~ 800 DEG C is reduced to 650 ~ 700 DEG C simultaneously, greatly reduce energy consumption, ketene gas is lowered the temperature through interchanger, heat energy obtains recycle, really achieves energy-saving and cost-reducing.
embodiment:
Below in conjunction with specific embodiment, the present invention is further described, these embodiments are only not used in for illustration of the present invention and limit the scope of the invention, after having read the present invention, the amendment of those skilled in the art to the various equivalent equivalent form of value of the present invention has all fallen within the application's claims limited range.
Embodiment 1: a kind of preparation method of silicon dioxide carried tungstophosphoric acid:
Get 225.3g tetraethoxy, add 80.6g water, 5.6g ethanol, at 35 ~ 40 DEG C, hydrolysis obtains solution A; Get 35g tungstophosphoric acid, be dissolved in 10g ethanol and obtain solution B, solution B is poured in solution A, 82 ~ 88 DEG C of reactions 4 ~ 6 hours, then by aqueous gel 40 ~ 45 DEG C of vacuum-dryings, finally by xerogel 140 ~ 160 DEG C of dried overnight, the obtained silicon-dioxide tungstophosphoric acid 100g containing tungstophosphoric acid 35%.
Embodiment 2:
Acetic acid (content >=99.0%) and stopper 2, (acetic acid: stopper 2 after the mixing of 5-tert.-butyl phenol, 5-tert.-butyl phenol mass ratio=1:0.001), after acetate evaporator 120 DEG C vaporization, be preheated to 300 DEG C of gases and enter fixed-bed reactor, under 650 DEG C of conditions, under silicon dioxide carried tungstophosphoric acid catalyst (in embodiment 1 gained) effect, dehydration generates ketene, reaction time: 3S, ketene gas after interchanger is cooled to 160 DEG C, then obtains ketene finished product through brine cooler (-10 DEG C) cooling recovery.Throw acetic acid 1000g altogether, acetic acid transforms 99.2%, and selectivity 96.8%, obtains ketene 661.7g, and ketene yield is 95.3%.
Embodiment 3:
Acetic acid (content >=99.0%) and stopper dimethyl formamide mixing rear (acetic acid: stopper dimethyl formamide mass ratio=1:0.01), after acetate evaporator 130 ± 2 DEG C vaporization, be preheated to 340 ± 5 DEG C of gases and enter fixed-bed reactor, under 670 ± 1 DEG C of conditions, under silicon dioxide carried tungstophosphoric acid catalyst (in embodiment 1 gained) effect, dehydration generates ketene, reaction time: 5S, ketene gas after interchanger is cooled to 135 ± 5 DEG C, then obtains ketene finished product through brine cooler (-15 ± 2 DEG C) cooling recovery.Throw acetic acid 1000g altogether, acetic acid transforms 99.0%, and selectivity 96.3%, obtains ketene 665.3g, and ketene yield is 96.0%.
Embodiment 4:
Acetic acid (content >=99.0%) and stopper 3, (acetic acid: stopper 3 after the mixing of 5-tertiary butyl-4-hydroxy phenylcarbinol, 5-tertiary butyl-4-hydroxy phenylcarbinol mass ratio=1:0.02), after acetate evaporator 130 ± 2 DEG C vaporization, be preheated to 370 ± 5 DEG C of gases and enter fixed-bed reactor, under 670 ± 1 DEG C of conditions, under silicon dioxide carried tungstophosphoric acid (in embodiment 1 gained) catalyst action, dehydration generates ketene, reaction time: 6S, ketene gas is after interchanger is cooled to 145 ± 5 DEG C, ketene finished product is obtained again through brine cooler (-20 ± 2 DEG C) cooling recovery.Throw acetic acid 1000g altogether, acetic acid transforms 99.3%, and selectivity 96.1%, obtains ketene 663.1g, and ketene yield is 95.4%.
Embodiment 5:
Acetic acid (content >=99.0%) and stopper acrylamide mixing rear (acetic acid: stopper the proportion of acylamide=1:0.03), after acetate evaporator 140 DEG C vaporization, be preheated to 400 DEG C of gases and enter fixed-bed reactor, under 700 DEG C of conditions, under silicon dioxide carried tungstophosphoric acid catalyst (in embodiment 1 gained) effect, dehydration generates ketene, reaction time: 10S, ketene gas after interchanger is cooled to 110 DEG C, then obtains ketene finished product through brine cooler (-30 DEG C) cooling recovery.Throw acetic acid 1000g altogether, acetic acid transforms 99.5%, and selectivity 96.4%, obtains ketene 667.9g, and ketene yield is 95.9%.
Embodiment 6:
Acetic acid (content >=99.0%) and stopper methane amide mixing rear (acetic acid: stopper methane amide mass ratio=1:0.005), after acetate evaporator 130 ± 2 DEG C vaporization, be preheated to 370 ± 5 DEG C of gases and enter fixed-bed reactor, under 690 ± 1 DEG C of conditions, under silicon dioxide carried tungstophosphoric acid catalyst (in embodiment 1 gained) effect, dehydration generates ketene, reaction time: 8S, ketene gas after interchanger is cooled to 155 ± 5 DEG C, then obtains ketene finished product through brine cooler (-20 ± 2 DEG C) cooling recovery.Throw acetic acid 1000g altogether, acetic acid transforms 99.5%, and selectivity 96.4%, obtains ketene 664.4g, and ketene yield is 95.4%.
Comparative example:
Acetic acid (content >=99.0%) and catalyzer Secondary ammonium phosphate mixing rear (acetic acid: Secondary ammonium phosphate mass ratio=1:0.008), after acetate evaporator 130 DEG C vaporization, enter acetic acid cracking stove, ketene gas is cracked under 700 ~ 800 DEG C of conditions, reaction time is 5 ~ 15S, and the ketene gas of generation obtains ketene finished product through brine cooler (-10 ~-30 DEG C) cooling recovery again.Throw acetic acid 1000g altogether, acetic acid transforms 95.3%, and selectivity 90.2%, obtains ketene 573.0g, and ketene yield is 85.9%.
Claims (5)
1. a synthetic method for acetic acid dehydration ketene, is characterized in that: comprise the following steps: successively
(1) one that to be the described stopper of 1: 0.03 ~ 0.001 mixing in mass ratio by acetic acid and stopper be in sterically hindered phenol or amides, then through acetate evaporator 120 ~ 140 DEG C vaporization;
(2) enter fixed-bed reactor by behind step (1) gained air preheat to 300 ~ 400 DEG C, under 650 ~ 700 DEG C of conditions, contact with the silicon dioxide carried tungstophosphoric acid of catalyzer and dehydration reaction occurs, generate ketene gas;
(3) by step (2) described ketene gas, after interchanger is cooled to 110 ~ 160 DEG C, then through brine cooler cooling, reclaims and obtain ketene finished product.
2. synthetic method according to claim 1, is characterized in that: described fixed-bed reactor are calandria type fixed bed reactor.
3. synthetic method according to claim 1, is characterized in that: the time of described dehydration reaction is 3-10S.
4. synthetic method according to claim 1, is characterized in that: the preparation method of described silicon dioxide carried tungstophosphoric acid is: tetraethoxy is dissolved in 6 ~ 15% ethanolic solns, and at 35 ~ 40 DEG C, hydrolysis obtains solution A; Tungstophosphoric acid is dissolved in dehydrated alcohol and obtains solution B, solution B is poured in solution A, 82 ~ 88 DEG C of reactions 4 ~ 6 hours, then by aqueous gel 40 ~ 45 DEG C of vacuum-dryings, finally by xerogel 140 ~ 160 DEG C of dried overnight, obtained tungstophosphoric acid content 10% ~ 40% silicon dioxide carried tungstophosphoric acid.
5. synthetic method according to claim 1, is characterized in that: the temperature of described brine cooler cooling is-10 ~-30 DEG C.
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| CN201310587988.1A CN103570519B (en) | 2013-11-21 | 2013-11-21 | Synthetic method for preparing ketene by dehydrating acetic acid |
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| CN201310587988.1A CN103570519B (en) | 2013-11-21 | 2013-11-21 | Synthetic method for preparing ketene by dehydrating acetic acid |
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| CN103570519B true CN103570519B (en) | 2015-06-24 |
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| CN110052259B (en) * | 2019-04-29 | 2020-08-25 | 浙江大学 | Preparation and application of silicon dioxide coating type monolithic catalyst |
| CN110283060A (en) * | 2019-07-12 | 2019-09-27 | 抚顺顺特化工有限公司 | A kind of synthesis technology of 3.3 dimethacrylate |
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| US2175811A (en) * | 1936-10-28 | 1939-10-10 | Du Pont | Manufacture of ketenes |
| DE19734275A1 (en) * | 1997-08-07 | 1999-02-11 | Hoechst Ag | Use of phosphoric acid as a catalyst in the production of ketene |
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