CN1094922C - Method for preparing oxalic acid by using diethyl oxalate - Google Patents
Method for preparing oxalic acid by using diethyl oxalate Download PDFInfo
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- CN1094922C CN1094922C CN00100077A CN00100077A CN1094922C CN 1094922 C CN1094922 C CN 1094922C CN 00100077 A CN00100077 A CN 00100077A CN 00100077 A CN00100077 A CN 00100077A CN 1094922 C CN1094922 C CN 1094922C
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- oxalic acid
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- diethyl ester
- water
- diethyl oxalate
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Abstract
The present invention discloses a method for preparing oxalic acid by diethyl oxalate. The method takes the diethyl oxalate as a main raw material, the oxalic acid is directly prepared via hydrolysis reaction, and the preparation processes are mainly carried out in a reaction distillation tower. The present invention is characterized in that the charged weight ratio of water to ester is 1.60 to 3.50, reaction temperature is 100 to 110 DEG C at atmospheric pressure, an oxalic acid solution generated from the tower bottom is crystallized in a crystallizer, and mother liquor is circularly used and supplies water into the water. The present invention has the characteristics of no environmental pollution in the preparation processes and simple processing of the products, and the conversion rate of the diethyl oxalate is more than 97%, and the yield of the oxalic acid is more than 87%.
Description
The present invention relates to a kind of method for preparing oxalic acid with oxalic acid diethyl ester.It belongs to the PREPARATION OF OXAlIC ACID technology.
Oxalic acid is a kind of one of important source material of preparing in various dyestuffs, intermediate, medicine, agricultural chemicals that can be used for.Present stage, the production method of oxalic acid was based on the sodium formiate dehydriding, this method not only needs to consume a large amount of acid, alkali, and discharges a large amount of lead salt and obnoxious flavour in reaction, and environmental pollution is comparatively serious, for this reason, people are constantly seeking the green production method of oxalic acid.At present, the method for preparing oxalic acid with oxalic acid diethyl ester becomes one of research topic that people are paid close attention to.In relevant bibliographical information, point out: when adopting tank reactor to carry out batch fractionating operation preparation oxalic acid, in reaction system, add acid, alkali, attempt to accelerate speed of reaction, but this measure there is not the change of essence to the yield of oxalic acid diethyl ester transformation efficiency and oxalic acid.The transformation efficiency of oxalic acid diethyl ester and the yield of oxalic acid are still lower, are respectively 75%, 70%, and bring very big difficulty for the mask work of the aftertreatment of product.
Purpose of the present invention is to provide a kind of method for preparing oxalic acid with oxalic acid diethyl ester.This method has environmentally safe, oxalic acid diethyl ester transformation efficiency and the high characteristics of oxalic acid yield.
For achieving the above object, the present invention is realized by following technical proposals.With the oxalic acid diethyl ester is raw material, the direct hydrolysis reaction, the main method that adopts reaction fractionating tower to produce oxalic acid, it is characterized in that: water and oxalic acid diethyl ester enter in the tower with the top of weight ratio 1.60～3.50 inlet amounies by tower, and the tower still is operated in 100～110 ℃ under normal pressure, cat head output ethanol water removes knockout tower again, the output oxalic acid solution decrystallizes and carries out crystallization at the bottom of the tower, and Recycling Mother Solution is used, and keeps the skin wet in tower.
Accompanying drawing is a reaction fractionating tower synoptic diagram of the present invention.1 is oxalic acid solution output mouth among the figure, and 2 is the Recycling Mother Solution pipeline, and 3 are reinforced import, and 4 are the outlet of ethanol aquatic products.
Below the present invention is described in detail.
Low at raw material oxalic acid diethyl ester solubleness in water, it is slower that water at normal temperature is separated speed of reaction, add acid, basic hydrolysis agent to improving the unconspicuous characteristics of speed of reaction, the present invention influences this factor from improving temperature of reaction to speed of reaction emphatically, improved temperature of reaction greatly, the operant response temperature is controlled at 100～110 ℃, under this temperature condition, not only help having improved speed of reaction, and help the cat head alcoholic acid and steam.In addition, having determined suitable water ester charge ratio, also is to improve the transformation efficiency of oxalic acid diethyl ester and important factor of yield of oxalic acid.If in water to ester ratio, moisture is too high, although transformation efficiency is higher, energy consumption is bigger, and the yield of oxalic acid is too low.Otherwise the ratio of water very little, and the transformation efficiency of oxalic acid diethyl ester is lower again.
The present invention is a hydrolytic reagent with having now to add acid, to add alkali, and employing device at intermittence prepares the method for oxalic acid to be compared, and its evident characteristic is, the production process non-environmental-pollution, product postprocessing is simple, and the transformation efficiency of oxalic acid diethyl ester can reach more than 97%, and the yield of oxalic acid can reach more than 87%; Though energy consumption is higher in the reactive distillation processes, from revenue and expenditure recently, it is worthwhile that economic benefit remains.
The invention will be further described with embodiment more below.
Embodiment one
In the reaction fractionating tower still, add the mother liquor that 320ml contains a small amount of oxalic acid, heat temperature raising is also carried out full tower and is refluxed, then on tower top with 60 Grams Per Hours, 150 Grams Per Hour feed rates add oxalic acid diethyl ester and water in tower, after the feed time to 10 minute, adjusting reflux ratio is 2.4: 1, the service temperature of tower is 98 ℃, this moment by cat head output ethanol water, output oxalic acid solution at the bottom of the tower, the tower smooth running is after 5 hours; Measure by analysis, adjust, the oxalic acid diethyl ester transformation efficiency is 97%, and the yield of oxalic acid is 90%.
Embodiment two
Operational condition is identical with embodiment one, changes water ester inlet amount, oxalic acid diethyl ester 64 Grams Per Hours, and water is 210 Grams Per Hours, and reflux ratio is adjusted into 2: 1, tower operation 4 hours, the oxalic acid diethyl ester transformation efficiency is 98%, the yield of oxalic acid is 87%.
Claims (1)
1. method for preparing oxalic acid with oxalic acid diethyl ester, be to be main raw material with the oxalic acid diethyl ester, directly pass through hydrolysis reaction, the main reaction fractionating tower that adopts is realized preparation process, and it is characterized in that: water and oxalic acid diethyl ester are entered in the tower by tower top with weight ratio 1.60～3.50 inlet amounies, and the tower still is operated in 100～110 ℃ under normal pressure, cat head output ethanol water also removes knockout tower again, the output oxalic acid solution device that decrystallizes carries out crystallization at the bottom of the tower, and Recycling Mother Solution is used, and keeps the skin wet in tower.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN00100077A CN1094922C (en) | 2000-01-06 | 2000-01-06 | Method for preparing oxalic acid by using diethyl oxalate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN00100077A CN1094922C (en) | 2000-01-06 | 2000-01-06 | Method for preparing oxalic acid by using diethyl oxalate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1263082A CN1263082A (en) | 2000-08-16 |
| CN1094922C true CN1094922C (en) | 2002-11-27 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN00100077A Expired - Fee Related CN1094922C (en) | 2000-01-06 | 2000-01-06 | Method for preparing oxalic acid by using diethyl oxalate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1094922C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104892400B (en) * | 2015-06-02 | 2016-09-07 | 福州大学 | Catalyze and synthesize oxalic acid intermittent reaction and continuous reaction rectification group technology |
| CN113307736A (en) * | 2021-06-29 | 2021-08-27 | 河南心连心化学工业集团股份有限公司 | Device and method for producing oxalic acid by using byproduct oxalate produced in process of preparing ethylene glycol from coal |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5498715A (en) * | 1978-01-11 | 1979-08-03 | Ube Ind Ltd | Preparation of oxalic acid |
-
2000
- 2000-01-06 CN CN00100077A patent/CN1094922C/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5498715A (en) * | 1978-01-11 | 1979-08-03 | Ube Ind Ltd | Preparation of oxalic acid |
Non-Patent Citations (1)
| Title |
|---|
| 天然气化工，第20卷第4期 1995.1.1 陈锦文等，草酸二乙酯水解反应动力学研究 * |
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| Publication number | Publication date |
|---|---|
| CN1263082A (en) | 2000-08-16 |
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