CN114315519A - Method for purifying high-purity organic solvent methanol - Google Patents

Abstract

A method for purifying methanol as a high-purity organic solvent disclosed in the present invention comprises the following steps: (1) removing impurities: removing impurities from methanol raw materials with a purity of 90% through nano-silicon adsorption to obtain refined methanol; (2) removing the steps (1) The obtained refined methanol is oxidized and pumped into the reaction kettle, oxidant and sulfuric acid are added, refluxed for 2 h to 4 h, and methanol is distilled out; (3) Reductive distillation: the distilled methanol is pumped into the reduction distillation kettle, and a reducing agent is added to carry out Reductive rectification, heating with heat-conducting oil, controlling the temperature of the heat-conducting oil to 100℃～200℃, the methanol liquid temperature in the rectification kettle is 70℃～78℃, the top temperature is 64℃～67℃, the reflux ratio is controlled to 10:4～5, and the removal of The first fraction and the distillate are filtered to obtain high-purity methanol product. The invention uses methanol with a content of 90% as a raw material, which reduces the cost of raw materials.

Description

Method for purifying high-purity organic solvent methanol

Technical Field

The invention belongs to the field of chemical reagents, and relates to a method for purifying and preparing a high-purity organic solvent, in particular to a method for purifying a high-purity organic solvent methanol for scientific research.

Background

The method for preparing pesticide residue grade and gradient elution grade chromatographic methanol is rarely reported in China. The pesticide residue reagent is a high-purity reagent used in pesticide residue detection, and the purity requirement of the pesticide residue reagent is higher than that of a common chromatographic pure reagent. Due to the serious dependence of agricultural product production on pesticide, pesticide residue in the agricultural product exceeds the standard, and the edible safety of consumers and the external trade of the agricultural product are influenced. Therefore, the country increases the detection strength of pesticide residues, increases the detection types of pesticides and improves the detection accuracy. Therefore, timely and accurate detection of pesticide residue in agricultural products is a key ring for avoiding overproof pesticide residue in agricultural products.

At present, pesticide residue grade and gradient elution grade reagents in China mainly depend on import, and the research work in the field is not slow. Therefore, the research on the preparation and purification methods of the pesticide residue grade and gradient elution grade chromatographic methanol reagents is of great significance.

Therefore, the Chinese patent application publication No. CN101570467A discloses a method for purifying a high-purity organic solvent methanol for scientific research, which comprises the following steps: oxidizing, reducing, rectifying and filtering to obtain the high-purity methanol finished product. The method takes methanol with the content of 99.5 percent as a raw material, utilizes the difference of impurity properties, removes impurities from the impurities containing a small amount of unsaturated hydrocarbon and alcohol through oxidation, reduction and rectification, and then purifies the impurities to obtain pesticide residue grade and gradient elution grade chromatographic methanol products with the purity of more than 99.9 percent, the yield of more than 95 percent, and obtains the pesticide residue grade and gradient elution grade chromatographic pure methanol with the purity of more than 90 percent. However, this patent application requires high-concentration methanol as a raw material, and is expensive.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides the method for purifying the high-purity organic solvent methanol, which has the advantages of low raw material cost, simple process, high yield and high product purity.

The purpose of the invention is realized by the following technical scheme:

a method for purifying high-purity organic solvent methanol comprises the following steps:

(1) removing impurities: removing impurities from a methanol raw material with the purity of 90 percent by nano-silicon adsorption to obtain refined methanol;

(2) oxidizing the refined methanol obtained in the step (1) and putting the refined methanol into a reaction kettle, adding hydrogen peroxide or potassium permanganate and sulfuric acid, wherein the amount of the added oxidant is 0.5-1.0% of the mass of the methanol raw material, and the amount of the added sulfuric acid is 0.1-0.4% of the mass of the methanol raw material, refluxing for 2-4 h, and distilling out the methanol;

(3) reduction and rectification: and (2) putting the distilled methanol into a reduction and rectification kettle, adding a reducing agent calcium hydride, wherein the amount of the reducing agent is 0.2-0.8% of the mass of the methanol, carrying out reduction and rectification, heating by utilizing heat conduction oil, controlling the temperature of the heat conduction oil to be 100-200 ℃, the temperature of the methanol liquid in the rectification kettle to be 70-78 ℃, the temperature of the top part to be 64-67 ℃, controlling the reflux ratio to be 10: 4-5, removing the initial fraction, and filtering the distillate to obtain the high-purity methanol finished product.

The invention has the advantages and positive effects that:

1. the method takes methanol with the content of 90 percent as a raw material, firstly adopts nano-silicon to adsorb impurities and water to obtain refined methanol, then utilizes the difference of the properties of the impurities of the refined methanol to remove a small amount of unsaturated hydrocarbon and alcohol impurities by oxidation reduction, and then carries out rectification purification to obtain a chromatographic methanol product with the purity of more than 99.9 percent, wherein the yield is more than 95 percent, thereby obtaining the pesticide residue grade and gradient elution grade chromatographic methanol product with the purity of more than 90 percent. The invention uses 90% methanol as raw material, which reduces the cost of raw material.

2. The invention adopts hydrogen peroxide or potassium permanganate as an oxidant and calcium hydride as a reducing agent to carry out oxidation-reduction reaction, and adopts distillation and rectification processes to purify the methanol, thus having the advantages of high product purity, simple and convenient operation, stable operation, suitability for mass production and the like.

Detailed Description

The present invention is further illustrated by the following examples, which are intended to be illustrative, not limiting and are not intended to limit the scope of the invention.

The nano-silicon used in the following examples is prepared by a method disclosed in CN201410306486.1 for producing nano-silicon from rice hulls.

Example 1:

a method for purifying high-purity organic solvent methanol comprises the following steps:

(1) removing impurities: removing impurities from 15kg of methanol raw material with the purity of 90% by nano-silicon adsorption to obtain refined methanol;

(2) and (3) oxidation: putting the refined methanol prepared in the step (1) into a 20L oxidation kettle, adding 75g of oxidant hydrogen peroxide and 15g of acid medium sulfuric acid, refluxing for 4h, and quickly evaporating the oxidized methanol;

(3) reduction and rectification: and (3) putting the oxidized methanol into a reduction kettle, adding 30g of reducing agent calcium hydride, and carrying out reduction rectification. Heating by using heat conducting oil, controlling the temperature of the heat conducting oil to be 100-150 ℃, the temperature of methanol liquid in the rectifying still to be 70-78 ℃, the temperature of the top part to be 64-67 ℃, controlling the reflux ratio to be 10: 4-5 (all displayed on an instrument control box), properly controlling the rectifying temperature and adjusting the reflux ratio, and controlling the water content of the methanol effluent. Removing initial fraction, filtering the qualified distillate with 0.45 μm VDF microporous membrane to obtain high purity methanol product, bottling, and storing under nitrogen.

Example 2:

a method for purifying high-purity organic solvent methanol comprises the following steps:

(1) removing impurities: removing impurities from 10kg of methanol raw material with the purity of 90% by nano-silicon adsorption to obtain refined methanol;

(2) and (3) oxidation: putting 10kg of raw material chromatographic methanol with the content of 99.5 percent into a 20L oxidation kettle, adding 100g of potassium permanganate serving as an oxidant and 4.5g of sulfuric acid serving as an acidic medium, refluxing for 4 hours, and quickly evaporating the oxidized methanol;

(3) reduction and rectification: and (2) pumping the oxidized methanol into a reduction and rectification kettle, adding 80g of reducing agent calcium hydride, carrying out reduction and rectification, heating by utilizing heat conduction oil, controlling the temperature of the heat conduction oil to be 150-200 ℃, the temperature of methanol liquid in the rectification kettle to be 70-78 ℃, the temperature of the top part to be 64-67 ℃, and controlling the reflux ratio to be 10: 4-5 (all the methanol liquid is displayed on an instrument control box). The water content of the methanol effluent can be controlled by properly controlling the rectification temperature and adjusting the reflux ratio. Removing initial fraction, filtering the qualified distillate with 0.45 μm VDF microporous membrane to obtain high purity methanol product, bottling, and storing with nitrogen gas.

Claims (1)

1. A method for purifying high-purity organic solvent methanol is characterized by comprising the following steps:

(1) removing impurities: removing impurities from a methanol raw material with the purity of 90 percent by nano-silicon adsorption to obtain refined methanol;

(2) oxidizing the refined methanol obtained in the step (1) and putting the refined methanol into a reaction kettle, adding hydrogen peroxide or potassium permanganate and sulfuric acid, wherein the amount of the added oxidant is 0.5-1.0% of the mass of the methanol raw material, and the amount of the added sulfuric acid is 0.1-0.4% of the mass of the methanol raw material, refluxing for 2-4 h, and distilling out the methanol;

(3) reduction and rectification: and (2) putting the distilled methanol into a reduction and rectification kettle, adding a reducing agent calcium hydride, wherein the amount of the reducing agent is 0.2-0.8% of the mass of the methanol, carrying out reduction and rectification, heating by utilizing heat conduction oil, controlling the temperature of the heat conduction oil to be 100-200 ℃, the temperature of the methanol liquid in the rectification kettle to be 70-78 ℃, the temperature of the top part to be 64-67 ℃, controlling the reflux ratio to be 10: 4-5, removing the initial fraction, and filtering the distillate to obtain the high-purity methanol finished product.