Green technology for preparing n-valeric acid from low-purity n-valeraldehyde by air oxidation

A technology of air oxidation and n-valeraldehyde, applied in the preparation of organic compounds, carboxylate preparation, organic chemistry, etc., can solve the problems of high cost of raw materials, and achieve the effects of high selectivity, less side reactions, and mild reaction conditions

Inactive Publication Date: 2016-11-23
HUNAN INSTITUTE OF SCIENCE AND TECHNOLOGY +1
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0004] The raw material n-valeraldehyde manufacturers mainly include American Dow Chemical Company, Yuanlian Carbide Chemical Company and

Method used

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  • Green technology for preparing n-valeric acid from low-purity n-valeraldehyde by air oxidation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Preparation of n-valeric acid in the laboratory: In a self-made bubbling reactor with an inner diameter of 46 mm and a length of 150 cm with a jacket, the n-valeraldehyde was directly oxidized by air to prepare n-valeric acid. By using a temperature-controllable circulating water pump to adjust the internal temperature of the bubbling reactor, the internal temperature of the reactor is kept constant. Air is bubbled in from below the bubble column. Weigh 100 g of 93.8% n-valeraldehyde and add it into a bubbling reactor with glass spring packing, use an air compressor to blow air in at a rate of 700 mL / min, control the reaction temperature at 80 °C, and track it with gas chromatography reaction. After reacting for 8 h, samples were taken for gas chromatography test, and the content of n-valeric acid was 94.5%, the conversion rate of n-valeraldehyde was 99.3%, and the selectivity was 98.5%.

Embodiment 2

[0019] The difference from Example 1 is that hydrogen peroxide is used as the oxidizing agent instead. Weigh 100 g of 93.8% n-valeraldehyde and add it into a 500mL reaction bottle. According to the molar ratio of n-valeraldehyde and hydrogen peroxide at 1:2, add 30% hydrogen peroxide dropwise. The reaction temperature is controlled at 80°C and the reaction time is controlled at After 8 h, the reaction was followed by gas chromatography. The result obtained by the reaction of Example 2: the conversion rate of n-valeraldehyde is 30%, the content of n-valeric acid is 23%, and the impurity content is high.

Embodiment 3

[0021] The difference from Embodiment 1 lies in: workshop scale-up. Weigh 600 kg of 93.8% n-valeraldehyde and add it into a stirred bubbler reactor, use an air compressor to blow air at a rate of 1500 L / min, control the reaction temperature at 80 °C, and use gas chromatography to track the reaction. After reacting for 20 h, samples were taken for gas chromatography test, and the content of n-valeric acid was 94.3%, the conversion rate of n-valeraldehyde was 97.5%, and the selectivity was 99.0%. Take 500 kg of the reaction solution for vacuum distillation to purify n-valeric acid, and collect fractions at 118-120°C. Obtain 22 kg of cuts with 75.1% n-valeric acid content, 434 kg of cuts with more than 98% n-valeric acid content, 35 kg of raffinate with 80.2% n-valeric acid content at the bottom of the still, and a single rectification with a purity of more than 98% n-valeric acid The acid yield was 86.8%. The components below 98% can be combined for secondary distillation and ...

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Abstract

The invention discloses a green technology for preparing n-valeric acid from low-purity n-valeraldehyde by air oxidation. The green technology includes the steps: adding the low-purity n-valeraldehyde into a stirred bubbling tank reactor with outer circulation; bubbling into air or oxygen or oxygen-enriched air or oxygen-denuded air; decompressing, rectifying and purifying for products after oxidation reaction to obtain the n-valeric acid with purity of more than 98%. The content of the n-valeraldehyde is lower than 80%, air speed is 100-2000L/min, reaction temperature is 25-100 DEG C, reaction time is 1-30 hours, the conversion rate of the n-valeraldehyde reaches 97% or above, selectivity reaches 98% or above, single decompressing and distilling rate reaches 86% or above. By the aid of the green technology, the air serves as an oxidizing agent, any catalysts are omitted, and the green technology has the advantages of smooth reaction, high efficiency, low cost, green, environmental protection and the like and a wide application and market prospect.

Description

technical field [0001] The invention relates to a green process for preparing n-valeric acid by air oxidation of low-purity n-valeraldehyde. Background technique [0002] N-valeric acid is widely used in spices, and can be used to make flavors such as cream, cheese, strawberry, etc. It can also be used as raw materials for organometallic soaps, spices, pesticides and pharmaceuticals. It is an important chemical raw material. N-valeric acid is mainly used in the synthesis of valeric acid esters. The volatile valeric acid esters have a pleasant smell and can be used in perfumes and cosmetics. Ethyl valerate and amyl valerate have a fruity aroma and are used as food additives. n-valeric acid is obtained by electrolytic oxidation of n-pentanol; or from distillates of valerian root with other isomers; or by reaction of butyl bromide with sodium cyanide followed by saponification of the resulting valeronitrile And the system, the yield is 70 to 75%; can also be prepared by oxida...

Claims

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Application Information

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IPC IPC(8): C07C51/235C07C53/126
CPCC07C51/235C07C53/126
Inventor 杨长安华杰唐课文易健民阎建辉蒋卫和屈铠甲
Owner HUNAN INSTITUTE OF SCIENCE AND TECHNOLOGY
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