JP2000219644A - Batch-wise or continuous distillation of liquid including low boiling compound having propargyl group - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safe distillation method for the batch-wise or continuous distillation of a liquid including a low boiling compound having propargyl group. SOLUTION: This method is to distillate a liquid including a low boiling compound having propargyl group in the presence of an inert organic solvent having a nearly equal vapor pressure to that of the low boiling compound and to maintain the concentration of the low boiling compound in the liquid so as to be <=75 wt.% at all positions of the distillation system. It is preferable that the low boiling compound having propargyl group is propargyl chloride and the inert organic solvent is methyl t-butyl ether.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a batch or continuous distillation method, and more particularly, to a batch or continuous distillation method for a liquid containing a low-boiling compound having a propargyl group.

[0002]

2. Description of the Related Art A method for producing an intermediate compound such as an agricultural chemical using a low-boiling compound having a propargyl group is known. For example, Japanese Patent Application Laid-Open No. Hei 4-281838 discloses that Used, zinc and 25
5-methylfurfural in toluene in the presence of 5% ammonium chloride, the resulting reaction mixture is filtered, and the toluene solution of the filtrate is concentrated under reduced pressure to give 5-methyl-furyl propargyl carbinol. Is described.

[0003] Low-boiling compounds having 1 or 2 propargyl groups in the molecule and having 6 or less carbon atoms, such as propargyl chloride, are liquid at room temperature and are explosive when subjected to mechanical shock. When it is handled in large quantities, it is commercially available in a state diluted with toluene or the like.

[0004]

For example, when performing batch distillation of a liquid containing a low boiling point compound having a propargyl group on an industrial scale, an apparatus as shown in FIG. 1 is usually used. Are the top of the rectification column (S) (S
t), it was found that the concentration of the explosive low-boiling compound in the pool (K) and the trap (T) below the condenser (C) was increased. Then, it was considered that such a low-boiling compound having an explosive property present at a high concentration as a liquid poses a threat in terms of safety.

[0005]

The present inventors have conducted intensive studies to provide a safe distillation method when distilling a low-boiling compound-containing liquid having a propargyl group in a batch or continuous manner. Distilling the above-described liquid in the presence of an inert organic solvent having a vapor pressure substantially equal to the boiling point compound, and
The inventors have found that the above problem can be solved if the concentration of the low boiling point compound in the liquid is 75% by weight or less at all points in the distillation system, and completed the present invention.

That is, the present invention relates to a method for distilling a liquid containing a low-boiling compound having a propargyl group in a batch or continuous manner, wherein the inert organic solvent has a vapor pressure substantially equivalent to that of the low-boiling compound. The low boiling point compound having a propargyl group, wherein the concentration of the low boiling point compound in the liquid is 75% by weight or less at all points in the distillation system. A method for batch or continuous distillation of a liquid is provided. Hereinafter, the present invention will be described in detail.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of low boiling compounds having a propargyl group include propargyl chloride, propargyl bromide, ethyl propargyl ether,
Examples thereof include halides and etherified compounds such as dipropargyl ether, and mixtures thereof. Further, the low-boiling compound having a propargyl group or a mixture thereof may further contain a small amount of another explosive low-boiling compound such as, for example, allenyl bromide.

[0008] The total concentration of the low-boiling compound having a propargyl group in the low-boiling compound-containing liquid subjected to distillation is 75% by weight or less, and the other components have a vapor pressure substantially equal to that of the low-boiling compound. Inert organic solvents having, other than a small amount of other explosive low-boiling compounds such as allenyl bromide, for example, aromatic hydrocarbons such as toluene and xylene, chlorobenzene, o-dichlorobenzene, ethylene dichloride and the like Halogenated hydrocarbons, diisopropyl ether, ethers such as tetrahydrofuran and dioxane, ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and i-butyl acetate, alcohols such as methanol and ethanol,
And organic solvents such as acetic acid and organic acids such as propionic anhydride, and compounds having a high boiling point propargyl group such as 5-methyl-furyl propargyl carbinol.

The inert organic solvent having a vapor pressure substantially equal to that of the low-boiling compound preferably has a vapor pressure of a low-boiling compound having a propargyl group in a temperature range of at least 20 to 50 ° C. The difference is within 100 torr, more preferably, in addition to the above conditions, those having a higher vapor pressure than the low boiling point compound are exemplified. For example, the case where the low boiling point compound is propargyl chloride will be described as an example. Preferred inert organic solvents include methyl t-butyl ether, acetone, dichloroethane, trichloromethane, hexane, methylpentane and tetrahydrofuran. You. Among these organic solvents, methyl t-butyl ether is more preferred.

The amount of the inert organic solvent having substantially the same vapor pressure as the low-boiling compound is such that the concentration of the low-boiling compound in the liquid is 75% by weight or less at all points in the distillation system. If the low-boiling compound is propargyl chloride and the inert organic solvent having a vapor pressure substantially equal to that of the low-boiling compound is methyl t-butyl ether, methyl t-butyl ether is distilled off. At the start of the reaction, at least about 33 parts by weight, based on 100 parts by weight of propargyl chloride.

In the distillation method of the present invention, the distillation apparatus used may be of a batch type or a continuous type, and is not particularly limited. The distillation is carried out under reduced pressure or normal pressure while heating, if necessary. The distillation temperature varies depending on the operating pressure, but in the present invention, for example, a receiver (J), a pot (P), a rectification column (S), a condenser (C), a pipe (H), a trap (T), etc. At all points in the distillation system, the concentration of the low-boiling compound having a propargyl group in the liquid is set to be 75% by weight or less.

Low-boiling compounds having a propargyl group, other low-boiling compounds having explosive properties such as allenyl bromide, and compounds having a high-boiling propargyl group such as 5-methyl-furyl propargyl carbinol, etc. Is preferably set to be 75% by weight or less in the liquid at all points in the distillation system. Furthermore, the total concentration of the compound having a high boiling point propargyl group such as 5-methyl-furyl propargyl carbinol in the distillation still (R) at the end of the distillation is 75% by weight.
More preferably, it is set to be as follows.

[0013]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 In a mixture of 76 parts by weight of 5-methylfurfural, 180 parts by weight of toluene and 287 parts by weight of water, 320 parts by weight of a 25% by weight aqueous ammonium chloride solution, 77 parts by weight of zinc having an average particle diameter of 5 μm, and propargyl chloride 168 parts by weight of a 70.8% by weight toluene solution were added simultaneously at 45 ° C. over 30 minutes. Further, after reacting at the same temperature for 6 hours, the obtained reaction mixture was filtered. The filtrate was separated, the organic layer was washed with water, and the obtained toluene solution containing unreacted propargyl chloride was charged into the distillation still (R) of the apparatus shown in FIG. 1, and further, methyl t-butyl ether 111 was added. Part by weight was added and concentrated by distillation at 350 mmHg. After the pressure in the distillation system was returned to the atmospheric pressure to complete the concentration, the distillation apparatus was disassembled, and the concentration of the low-boiling point compound having a propargyl group in each part of the liquid was analyzed. Even in the lower reservoir (K) of the condenser where explosive low-boiling compounds are most likely to accumulate, the concentration of low-boiling compounds such as propargyl chloride in the liquid was 70% by weight or less. There is no mechanical shock in the distillation system, and the net amplitude of the mortar based on the ballistic mortar test result is that the concentration of propargyl chloride in methyl t-butyl ether is almost constant in the range of 0 to 75% by weight. Was confirmed.

The concentration of the low-boiling compound having a propargyl group in the gas phase in the distillation system was out of the gas explosion range.

According to the method of the present invention, a liquid containing a low-boiling compound having an explosive propargyl group can be safely distilled in a batch or continuous manner.

[Brief description of the drawings]

FIG. 1 shows a batch distillation apparatus used in an embodiment of the present invention.

[Explanation of symbols]

R distillation still, S rectification tower, H piping, C condenser, P pot, J receiver, T trap, V vacuum source

Continued on the front page F term (reference) 4D076 AA07 AA16 AA22 BB08 BB13 CD22 DA10 DA25 EA02Y EA03Y EA12Y EA14Y EA20Y EA23Y GA01 HA20 JA01 4H006 AA02 AD12 BB11 BB12 BB15 BB16 BB25 BC37 BD80 EA03 EB20

Claims (2)

[Claims] 1. A method for distilling a low-boiling compound-containing liquid having a propargyl group in a batch or continuous manner, wherein the liquid is distilled in the presence of an inert organic solvent having a vapor pressure substantially equivalent to that of the low-boiling compound. The contained liquid is distilled, and the concentration of the low-boiling compound in the liquid is 75
A batch or continuous distillation method for a low-boiling compound-containing liquid having a propargyl group, which is not more than 10% by weight. 2. The method according to claim 1, wherein the low-boiling compound having a propargyl group is propargyl chloride, and the inert organic solvent is methyl t-butyl ether.