CN101723828B - Method for preparing ethyl caproate by continuous esterification - Google Patents
Method for preparing ethyl caproate by continuous esterification Download PDFInfo
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- CN101723828B CN101723828B CN200810230588.4A CN200810230588A CN101723828B CN 101723828 B CN101723828 B CN 101723828B CN 200810230588 A CN200810230588 A CN 200810230588A CN 101723828 B CN101723828 B CN 101723828B
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- caproic acid
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- ethyl caproate
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Abstract
The invention discloses a method for preparing ethyl caproate by continuous esterification, which comprises the following steps of: mixing caproic acid and ethanol in the mol ratio of 1: (1-1.5), then preheating, esterifying by a fixed bed catalyst layer, then entering an ethanol fractionating tower, extracting 95%(V/V) alcohol obtained at the tower top, using the 95%(V/V) alcohol as a mixture and recycling; discharging the caproic acid and water from the tower bottom, separating out the caproic acid and recycling again; and leading out the total liquid phase from the position above a feed opening in the middle of the tower and naturally layering, wherein the upper layer is the water which reflows into the tower, and the lower layer is an ethyl caproate crude product which is extracted and refined separately. The method has the advantages that the method can operate within a wider esterification range without considering the conversion rate of the caproic acid; the unreacted caproic acid is separated from the water, thereby avoiding the defects of influencing the flavor of the ethyl caproate and reducing the yield caused by blackening and coking of the caproic acid due to heating when in conventional production and recovery; a neutralization washing work procedure is saved, and no neutralizing waste water exists; and the production efficiency is high.
Description
Technical field
The present invention relates to a kind of method of preparing ethyl caproate by continuous esterification, relate in particular to a kind of method that continuous high-efficient prepares ethyl hexanoate.
Background technology
Ethyl hexanoate is the theme fragrance ingredient of aromatic Chinese spirit, and the height of its content directly has influence on the quality of white wine.Because the conventional solid-state excise law is produced white wine, its yield of liquor is low, fragrance matter is few.The method that generally adopts of white spirit production technique is in recent years: with edible ethanol degree of falling, then add a part of solid state process liquor, then blend with the essence that contains ethyl hexanoate and form.So just make ethyl hexanoate become white wine and produce indispensable raw material, the usage quantity of annual national ethyl hexanoate is all more than 5000 tons, therefore reform the production method of ethyl hexanoate, select a technique simple, pollution-free, that quick, yield is high, energy-conservation to have practical significance.
At present, the preparation method of ethyl hexanoate adopts caproic acid and ethanol directly to carry out esterification mostly under heating condition, and the catalyzer of employing is sulfuric acid or highly acidic resin, and mode is intermittent type.Concrete operations are: add caproic acid and ethanol and catalyzer in still, after reflux esterification certain hour, steam the water that unreacted ethanol and reaction generate, then neutralize catalyst sulfuric acid and responseless caproic acid or the elimination catalyzer highly acidic resin responseless caproic acid that neutralizes again, at this moment material is divided into two-layer, the upper strata is ethyl hexanoate, and after washing, underpressure distillation gets product; Lower floor is mainly the Sodium n-caproate aqueous solution, reclaims caproic acid with sulfuric acid acidation.
Above technique has following defective: esterification yield is low, and sulfuric acid produces side reaction, and reaction water is told many power consumptions with vapour phase, and the alcohol that steams is not that finished product can not use by direct circulation, and the waste water that neutralization produces also needs the alkali that consume more, and production efficiency of equipment is low.
In order to improve the transformation efficiency of caproic acid, manufacturing enterprise and scientific research personnel have taked several different methods, have delivered many documents.The most frequently used method is to strengthen the consumption of ethanol, because the caproic acid costliness is again heat-sensitive substance, only has with the molar weight that increases ethanol to improve esterification yield; Graded esterified in addition, that is: first with the reaction of a part of ethanol and caproic acid, the water that esterification is generated steams, then adds that alcohol carries out for the second time and esterification for the third time; Application number is that 86104220 document is to add dehydrated alcohol in the esterification later stage to dewater to increase esterification yield; More document is that research changes catalyzer, is that 98111912 document improves esterification yield with changing catalyzer and adding water-retaining agent as application number; Also have other many pieces relevant for the report of ethyl hexanoate production, these researchs can be summed up as three classes substantially:
1, improve a kind of volumetric molar concentration of raw material;
2, change kind or the catalysis process of catalyzer;
3, slough water in the esterification process reaction mass, so that reaction is carried out to positive dirction.
These methods generally speaking all go to put forth effort from improving the esterification yield aspect, in use exist following defective: increase the mole number of feed ethanol, improve that to have lacked esterification yield high few, improve more yields larger, energy consumption is larger, and loss is more; Change catalyzer and can only relatively improve several percentage points of esterification yields, can not reach whole conversions, also have separation problem; Add water-retaining agent to dewater in reaction, time-consuming power consumption, cost is high.
Summary of the invention
The object of the present invention is to provide a kind of method of preparing ethyl caproate by continuous esterification, to improve esterification rate, reduce production costs.
To achieve these goals, technical scheme of the present invention has adopted a kind of method of preparing ethyl caproate by continuous esterification, the method is to make up with the ethanol separation column catalyst fixed bed, form the equipment of a cover continuous esterification, with caproic acid and ethanol 1:(1-1.5 in molar ratio) ratio prepare burden, then carry out preheating, through the esterification of fixed bed catalyst layer, then enter the ethanol separation column; Catalyzer in the fixed bed catalyst layer is highly acidic resin, immobilized enzyme or solid catalyst, has avoided some side reactions of using sulfuric acid to bring; From the middle and lower part charging of ethanol separation column, under water vapour effect at the bottom of trim the top of column and tower, tower top obtains the extraction of 95% (V/V) alcohol and recycles as batching with esterifying liquid; Caproic acid in material and water are descending with phegma in tower, and the flash mouth is discharged at the bottom of tower, tells the upper strata caproic acid, recycles as batching.Water vapor in this tower is by the vaporizer indirect heating water generates that arranges at the bottom of tower, rather than as the alcohol distillation tower make thermal source with open steam, adopt this kind mode to reduce draining, avoid multi-band to walk caproic acid; Wherein Yi Banta is outside equipped with a quantizer above the opening for feed of tower body middle part, and by quantizer, after natural layering, lower floor is that water layer passes back into tower with whole liquid phases, and the upper strata is that the extraction of ethyl hexanoate crude product is refining separately.
Discharge water at the bottom of collecting tower, reclaim approximately 1-2% the caproic acid of wherein taking away.
Intermittence or the refining ethyl hexanoate of continuous tower are set separately.Under reduced pressure first distill out second alcohol and water a small amount of in thick ethyl hexanoate, then regulate reflux ratio and make caproic acid not overproof, what steam is exactly the product ethyl hexanoate.When at the bottom of tower or in still, the caproic acid content in material rises to 30% left and right from 1% left and right, material together is discharged to separating hexanoic acid and ethyl hexanoate in the separation column of front esterification system together with the front-end volatiles that steam, in order to avoid the high time heating blackening of caproic acid content coking reduces yield and affects product special flavour.
The present invention mainly changes the production method of ethyl hexanoate from separation angle, because which kind of esterification process no matter, also no matter adopt which kind of catalyzer, the last component of esterification is all ethyl hexanoate, caproic acid, four kinds of materials of second alcohol and water, different is that a certain component of method that has is many, a certain component that have is few, but all has at last separation.Separate conversely speaking, the product ethyl hexanoate and can improve esterification rate in the same old way, because the content of ethyl hexanoate affects balance and esterification rate too.The separation of these four kinds of storerooms, caproic acid and ethyl hexanoate and water do not dissolve, and even if the acid esters light specific gravity is mixed to also fine separation with water; The industrial technique that maturation is arranged of separation of ethanol and water; Remaining is separating of caproic acid and ethyl hexanoate, 206 ℃ of caproic acid boiling points, 166 ℃ of ethyl hexanoates, both boiling points differ 40 ℃, organic separation routinely, these two kinds of materials also can separate in certain tower, even if problem is that the temperature of charge in tower reactor also must be in the situation that more than 120 ℃ and need to have certain reflux ratio both could be separated under high vacuum, but at this moment caproic acid has begun blackening, and namely power consumption is time-consuming again.But ethyl hexanoate has characteristics, and it and water can form azeotropic, and azeotropic point is 97.2 ℃, and it is almost water and ester half and half that azeotropic forms, and like this with nearly 70 ℃ of the boiling point lowering of ethyl hexanoate, has greatly improved the relative volatility of caproic acid and ethyl hexanoate.Therefore, the carboxylate of separating hexanoic acid in a steam distillation tower, when total reflux operation is issued to balance, overhead extraction be the ethanol of 95% (v/v), be ethyl hexanoate and water near 97.2 ℃, tower middle part, should be caproic acid and water at the bottom of tower.And no matter how many esterification yields is, be not always the case.
Adopt method of the present invention, compare with present production method, have following advantage: (1) esterification rate is fast, because all catalyzer are all fast in the just esterification of time opening, produced ester and water in material, esterification rate just slows down, reach trim point general 4-6 hours, the present invention need not wait until trim point, and is therefore fast more than 5-6 times than the esterification equipment of equal tower diameter; (2) the esterification yield turndown ratio is large, no matter esterification yield is 40% or 60%, or larger this technique of esterification scope can move, and general technique, and when following, the technological operation of remainder is difficult to go on esterification yield 80%; (3) yield is high, and caproic acid is separated in water, and low and water vapor protection is arranged due to separation temperature, its color does not have the blackening coking all the time, has avoided the defective of heat-sensitive materials caproic acid because of the easy blackening coking of heat for a long time, and its rate of recovery is near theoretical value; (4) energy-conservation, water in the water that generates in reaction and used up ethanol takes out with liquid form, therefore saved the latent heat of vaporization, and caproic acid be also separating of ethyl hexanoate to separate and be to carry out simultaneously in the process of separating alcohol with liquid form, vaporization does not reflux separately, therefore also save to a certain extent the energy, reduced production cost; (5) saved in and operation, thoroughly avoided the generation of waste water, the pollution of having avoided the discharging because of waste water that surrounding environment is caused; (6) produce continuously, plant efficiency is high, and is easy to operate, and turndown ratio is large; (7) good product quality, all processes service temperature do not surpass 110 ℃, and the required temperature of existing production method is more than 120 ℃, and in the production process of spices and essence, temperature is lower, and the product special flavour of producing is better; (8) equipment is easily made, and is simple to operate.Method of the present invention has good social value and economic worth, is easy to apply.
Embodiment
Embodiment 1
The method of continuous production ethyl hexanoate of the present invention, comprise the following steps: 1.5 cubic metres of highly acidic resins of filling in the stainless steel column of diameter 600mm, end opening connects preheater, the a certain plate in separation of ethanol tower middle and lower part that connects suitable for reading, the separation of ethanol tower is the inclined hole sieve-tray tower of diameter 500mm, several 65 plates of plate are installed a vaporizer at the bottom of tower, vaporize water produces water vapour and makes thermal source.With caproic acid and ethanol in molar ratio the ratio of 1:1.3 prepare burden in material-compound tank, use the pump dnockout, pass through under meter, flow flows through preheater for per hour 1 ton, when temperature is risen to 80 ℃, enter knockout tower after entering the esterification of highly acidic resin layer, measuring esterification yield is 55% again.Wherein a plate tower is outside equipped with a quantizer above the opening for feed of separation of ethanol tower middle part, the whole liquid phases of this plate of extraction, in quantizer after natural layering, lower layer of water passes back into tower, the upper strata is thick ethyl hexanoate, consists of: ethyl hexanoate is the caproic acid, the second alcohol and water of 4% left and right of 95%, 1% left and right approximately, approximately per hour 400kg, refining separately.The top tower control reflux ratio makes alcoholic strength reach 95% (v/v), 200kg approximately per hour, the extraction circulation of again preparing burden.Caproic acid and water in esterifying liquid together move down with phegma, and the flash mouth is discharged at the bottom of tower, approximately per hour 400kg, layering after heat exchange, the upper strata is the caproic acid layer, contains a small amount of water, ethyl hexanoate, spirituosity, need not make with extra care hardly, directly recycles as the caproic acid batching.The bottom steam temperature is 106 ℃.When thick ethyl hexanoate is refining, separately establish intermittent column or continuous still battery tower, a small amount of front-end volatiles that contain the second alcohol and water are told in first underpressure distillation, then regulate the control of reflux ratio caproic acid not overproof, then what steam is exactly the finished product ethyl hexanoate.Reconcentration caproic acid not when at the bottom of tower or in still, caproic acid rises to 30% left and right from 1%, but forward in the ethanol separation column of front separating hexanoic acid and ethyl hexanoate again together with the front-end volatiles that first steam are mixed to one, and reclaim a small amount of ethanol in front-end volatiles.
Embodiment 2
The difference of the preparation method of the present embodiment and embodiment 1 only is: change the separation of ethanol tower into mixing column, ethyl hexanoate extraction mouth is following is that tray column, the first half are packing tower.The bottom steam temperature is 102 ℃.
It should be noted last that, above example only is illustrative rather than definitive thereof technical scheme of the present invention, although with reference to above-described embodiment, the present invention is had been described in detail, those of ordinary skill in the art is to be understood that: still can modify or be equal to replacement the present invention, and not breaking away from any modification or partial replacement of the spirit and scope of the present invention, it all should be encompassed in the middle of claim scope of the present invention.
Claims (6)
1. the method for a preparing ethyl caproate by continuous esterification, its feature comprises the following steps: with caproic acid and ethanol 1:(1-1.5 in molar ratio) ratio prepare burden, then carry out preheating, through the esterification of fixed bed catalyst layer, enter the ethanol separation column, tower top obtains 95%(V/V again) the alcohol extraction recycles as batching; Discharge caproic acid and water at the bottom of tower, tell caproic acid, again recycle; Draw whole liquid phases above the opening for feed at tower middle part, after natural layering, lower floor is water, passes back into tower, and the upper strata is that the extraction of ethyl hexanoate crude product is refining separately.
2. the method for preparing ethyl caproate by continuous esterification according to claim 1, it is characterized in that: the catalyzer in described fixed bed catalyst layer is highly acidic resin or immobilized enzyme.
3. the method for preparing ethyl caproate by continuous esterification according to claim 1, it is characterized in that: described ethanol separation column is the steam distillation tower.
4. the method for arbitrary described preparing ethyl caproate by continuous esterification according to claim 1-3, it is characterized in that: be provided with a vaporizer so that water is heated at the ethanol Fractionator Bottom, the water vapor of generation is as thermal source.
5. the method for preparing ethyl caproate by continuous esterification according to claim 1, is characterized in that: collect the water of discharging at the bottom of tower, reclaim wherein a small amount of caproic acid of dissolving, do the raw material recycle.
6. the method for preparing ethyl caproate by continuous esterification according to claim 1, it is characterized in that: during refining ethyl hexanoate, reconcentration caproic acid not when the caproic acid content in thick ethyl hexanoate at the bottom for the treatment of tower or in still rises to 30% left and right from 1% left and right forwards in the ethanol separation column separating hexanoic acid and ethyl hexanoate again to.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN200810230588.4A CN101723828B (en) | 2008-10-27 | 2008-10-27 | Method for preparing ethyl caproate by continuous esterification |
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| Application Number | Priority Date | Filing Date | Title |
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| CN200810230588.4A CN101723828B (en) | 2008-10-27 | 2008-10-27 | Method for preparing ethyl caproate by continuous esterification |
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| Publication Number | Publication Date |
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| CN101723828A CN101723828A (en) | 2010-06-09 |
| CN101723828B true CN101723828B (en) | 2013-06-19 |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102627557A (en) * | 2012-03-16 | 2012-08-08 | 西北师范大学 | Method for catalytic synthesis of ethyl hexanoate by NKC-9 macroporous dry hydrogen catalysis resin |
| CN103965040B (en) * | 2013-02-04 | 2016-05-18 | 中国石油化工股份有限公司 | A kind of method of preparing dibasic acid dimethyl ester |
| CN109503342B (en) | 2019-01-02 | 2019-11-12 | 山东新和成维生素有限公司 | A kind of preparation method of beta-unsaturated ketone |
| CN112501217A (en) * | 2021-02-04 | 2021-03-16 | 天津凯莱英制药有限公司 | Continuous preparation method of S- (+) -2, 2-dimethylcyclopropane carboxylic acid |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN86104220A (en) * | 1986-06-18 | 1987-12-30 | 国营吴江香料厂 | Novel process and equipment that ethyl hexanoate is produced |
| JP2733034B2 (en) * | 1994-05-25 | 1998-03-30 | 株式会社日本触媒 | Method for producing carboxylic acid ester |
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2008
- 2008-10-27 CN CN200810230588.4A patent/CN101723828B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN86104220A (en) * | 1986-06-18 | 1987-12-30 | 国营吴江香料厂 | Novel process and equipment that ethyl hexanoate is produced |
| JP2733034B2 (en) * | 1994-05-25 | 1998-03-30 | 株式会社日本触媒 | Method for producing carboxylic acid ester |
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Effective date of registration: 20210914 Address after: 057750 shoushansi Township, Guantao County, Handan City, Hebei Province (No. 4, Haoyang Road, Handan New Chemical Park) Patentee after: Hebei Kezheng Chemical Co.,Ltd. Address before: 475506 North Street, Yongxing Town, Weishi County, Henan Patentee before: Gu Changan |
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