JPS61100537A - Production of methanol having low water content - Google Patents

Abstract

PURPOSE:To produce methanol having low water content and suitable especially for the use in the quantitative analysis of water by Karl Fischer process, easily, by adding metallic magnesium powder and mercuric chloride to methanol, and distilling the mixture. CONSTITUTION:Methanol having low water content can be produced economically by adding metallic magnesium powder and mercuric chloride to methanol, and distilling the mixture by conventional method. The amount of the metallic magnesium is 0.1-0.7wt% based on methanol, and that of the mercuric chloride is 1/5-2/5pt.wt. per 1pt of the magnesium. The process can be carried out easily in a laboratory scale. Since the water content of methanol can be reduced remarkably, the consumption of Karl Fischer reagent can be decreased considerably by the use of the methanol in the quantitative analysis of water by Karl Fischer process.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing low moisture methanol.

In particular, the present invention relates to a method for producing methanol suitable for use in quantitative water content analysis using the Karl Fischer method.

(Prior art and its problems) Karl Fischer method (2-based moisture determination method is to add a certain amount of methanol to a 7-Ranuco (Karl Fischer flask), stir, and add Karl Fischer reagent dropwise to the methanol solution. After removing the water, add the water-containing test object (sample), and after transferring the water in the sample into methanol (secondary), drop the Karl Fischer solution again.

The water content in the sample is determined by eliminating the water in methanol.

Therefore, methanol is of poor quality (= does not necessarily have to be a reagent and is sufficient for industrial use, but in any case, if the water content is high, a large amount of Karl Fischer reagent is required to eliminate the water content, and Since the analysis time is also long, it is preferable that the water content in methanol be as low as possible.

However, the water content in methanol is 0.05 to 0.0 for industrial use.
1% by weight (Hereinafter, weight% is simply written as "chi") 0 in reagent
．． Since the content is approximately 0.05 to 0.08%, this poses a problem as it consumes a large amount of expensive Karl Fischer reagent.

Conventionally, methanol was distilled in batches and the middle distillate was used, but even this middle distillate still contained water with an OD of 30.05%, so it was not very effective. The present inventor has developed a method for obtaining low-moisture methanol (after conducting various studies, after subjecting methanol to a small amount of gold-grade magnesium powder and mercuric chloride). The present invention was completed by discovering that the water content in methanol can be significantly reduced by using black paper.

That is, the present invention is a method for preparing low-water organic methanol, which is characterized by adding methanol (metallic magnesium powder and mercuric chloride) and then distilling the mixture.

Detailed explanation of non-invention.

When mercuric chloride is added to methanol while stirring metal magnesium powder, water-based scum is generated and the reaction occurs smoothly.

The reaction is estimated to be based on the following equation.

2 Hz”F Mt → Mt (OH)t+■.

Since the reaction is exothermic, it is necessary to carry out the reaction while cooling, but it is sufficient to cool the container with water at room temperature.

The reaction ends at about 305+. The end of the reaction can be confirmed by the stoppage of hydrogen gas generation. When treating with metallic magnesium powder, if the addition of mercuric chloride is omitted, no hydrogen gas generation or heat generation is observed. , it is assumed that the above reaction does not occur.

The amount of metal magnesium powder added is 0 for methanol C;
．． The amount of mercuric chloride added is preferably 2 to 0.5%, and the appropriate amount of mercuric chloride is 1/'5 to 2/75 of the weight of the metal magnesium powder.

The low water content methanol of the present invention can be obtained by subjecting the methanol treated with magnesium metal powder and mercuric chloride to a batch black fraction in the same manner as in the prior art.

That is, for example, a black drawing device as shown in FIG. 1 is used.

Metallic magnesium powder and methanol treated with mercuric chloride are placed in a flask 1 and heated. The evaporated methanol is cooled and liquefied in the cooler 5 and stored in the receiver, or the first fraction with an evaporation temperature of less than 64.5°C is transferred to the receiver B12 (Yukat), and when the evaporation temperature reaches 65°C (2), it is stored in the receiver. All
Switch to.

As the evaporation of methanol progresses and the amount remaining in the flask 1 decreases, the evaporation temperature begins to rise above the boiling point of methanol, 65°C, but the distillation is stopped when the evaporation temperature reaches 67°C.

The methanol remaining in the flask is a so-called evaporation residue, and if it is to be disposed of by incineration, it cannot be disposed of as it is because it contains mercury compounds, but it can be easily recovered as metallic mercury using the following method. It can be disposed of.

That is, to 100 parts by weight of the evaporation residue, 200 to 300 parts by weight of water and 50 to 7 parts of hydrochloric acid at a concentration of 35 M were added, and 8 parts by weight of the evaporation residue were added.
When heated to about 0° C., mercuric chloride easily turns into metallic mercury, and by separating it with P paper or the like, it can be easily recovered as metallic mercury.

(Effects of the present invention) As described above, the present invention is a method in which methanol is treated with metal magnesium powder and mercuric chloride and then distilled, and low-moisture methanol can be easily obtained by this method. If this methanol is used for water determination using the Karl Fischer method, the amount of Karl Fischer reagent used can be greatly reduced. This method can also be easily implemented on a laboratory scale.

(Examples and Comparative Examples) The present invention will be explained in more detail with reference to Examples and Comparative Examples below, but the gist of the invention is not to be construed as being derivable from these unless modified.

Example 1 1 ton of methanol with a moisture content of JI 0.09% is placed in a 2-ton flask, and while stirring with Nutala, 511% of metallic magnesium powder is added, followed by 1.5% of mercuric chloride crystals.
Added t. At this time, the flask was cooled with water. The generation of hydrogen gas by the reaction was completed in about 20 minutes, but the mixture was stirred for 30 minutes just to be sure.

Thus obtained. Methanol treated with metallic magnesium powder and mercuric chloride was distilled using the apparatus shown in Figure 1. That is, this methanol was charged into flask 1, and flask 1 was heated by heater 14 via oil vane 13.

The evaporated methanol is transferred to Kurogato 2. It follows the adapter 4, liquefies it again in the cooler 5, and then puts it into the receiver B12.The boiling point of methanol is about 63°C at first, and gradually rises as the black surface approaches. When the boiling temperature reaches 64.5℃, turn off the switch cock9. The IO was operated and the liquid was received into the receiver All.

When the black surface further progressed and the boiling point temperature reached 67° C., the black surface was stopped, and the middle portion in the receiver was stored in a sealed container.

The water content in the liquid received in the receiver All is 0.00
It was 6%.

Example 2 The same operation as in Example 1 was performed except that the amounts of magnesium metal powder and mercuric chloride added were 3 t and 0.9 tI: epicenter, respectively. The water content in the obtained Nakabukuro was 0.009%.

Comparative Example 1 Methanol was blackened using the apparatus shown in FIG. 1 under the same conditions as in Example 1, omitting the pretreatment of methanol by adding gold, magnesium powder, and mercuric chloride. The water content of the obtained middle distillate was 0.06%.

[Brief explanation of the drawing]

FIG. 1 shows an example of a methanol black drawing device used in the present invention. In the figure 1... 7 Ranuko, 2... Kurogato, 3... Thermometer,
4...Adapter, 5...Cooler, 6. ... Cooling water inlet, 7... Positive water outlet, 8... Two-prong adapter, 9, 10... Switching cock, 11... Receiver A, 1
2... Receiver B, 13... Oil bath, 14... Heater

Claims (2)

[Claims] (1) Metallic magnesium powder and second chloride in methanol
A method for producing low-moisture methanol, which comprises adding mercury and then distilling it. (2) The amount of magnesium metal powder added is 0.1 to 0.7% by weight based on methanol, and the amount of mercuric chloride added is 1/5 to 2/5 of the weight of the magnesium metal powder. The manufacturing method according to item 1.