JPS5822096B2 - Method for producing aqueous sodium salt solution of 4-methoxycarbonyl-5,5-dimethylcyclohexane-1,3-dione enol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 4-methoxycarbonyl-5,5-dimethylcyclohexane-1,3-dione (hereinafter referred to as DME). The present invention relates to a method of reacting methyl oxide with a methanol solution of sodium methylate to obtain a sodium salt of DME enol as an aqueous solution.

DME is a compound useful as a pesticide intermediate, particularly as a herbicide intermediate as shown below.

(Unexamined Japanese Patent Publication No. 5L-131856) Conventional DME manufacturing methods include, for example, He1v.

Cbem-Acta, 35, 1752-1756 (1
952), as a similar synthesis method for 4-methoxycarbonyl-5,5-dimethylcyclohexane-1,3-dione, dimethyl malonate 1.06% in a methanol solution of about 20 parts containing 1 mol of sodium methylate. mol and menthyl oxide 1.02 mol were added dropwise, and after refluxing overnight, as much alcohol as possible was distilled off, the residue was poured into water, and the alkali insoluble matter was extracted with ether. The aqueous phase was precipitated with acid and extracted with ether. A method for solidifying the residue after distilling off the ether is described.

In this production method, not only an excessive amount of malonic acid dimethyl ester is used as a raw material, but also the sodium salt of DME enol solidifies when methanol is distilled off after the reaction, making it difficult to remove it from the reactor.
After extraction with ether and distilling off the ether, it becomes a viscous solid that is difficult to remove from the reactor, requiring complicated operations and equipment, and cannot be said to be an excellent industrial production method.

As a result of various studies on industrially advantageous production methods for DME, the present inventors found that after adding water to a reaction solution obtained by reacting dimethyl malonate, mesityl oxide, and a methanol solution of sodium methylate, They found that an aqueous solution of the sodium salt of DME enol can be obtained in high yield by distilling off methanol, and that the above reaction proceeds almost completely even when dimethyl malonate is used in an equivalent amount to mesityl oxide. The present invention has now been completed.

The present invention is based on the fact that the sodium salt of DME enol is extremely stable compared to common methyl esters.

Even if reaction water is added and methanol is almost completely distilled off at normal pressure, hydrolysis of DME enol sodium salt, which is an ester, does not occur.

According to the method of the invention, solidification of the product is avoided.

Also, when DME is required, the DM obtained by the present invention
It can be easily isolated from an aqueous solution of the sodium salt of E enol.

Furthermore, the present inventors determined the 0-acylation power of DME enol, γ
- It has been found that by using picoline or the like as a catalyst, the reaction can be easily carried out in a mixed solvent of a poorly water-soluble organic solvent and water (Japanese Patent Application No. 92220/1982).

The present invention can be said to be an advantageous method especially when the presence of water is allowed, such as for producing raw materials for the 0-acylation.

Malonic acid dimethyl ester used in the present invention,
Commercially available mesityl oxide is sufficient, but the yield decreases depending on the amount of water contained in the raw material.

In addition, the yield of sodium methylate decreases depending on the amount of potassium contained in the raw material.

The amounts of malonic acid dimethyl ester, mesityl oxide and sodium methylate used are preferably approximately equivalent in order to obtain a highly pure product.

For example, 1 mol of malonic acid dinotyl ester, 15-0.98 mol of mesityl oxide, and 1 mol of sodium methylate.

In the present invention, the amount of water added before methanol distillation is usually 150 to 300% per mole of malonic acid dimethyl ester.
It is.

The methanol distillation is preferably carried out at normal pressure in order to suppress the distillation of water and prevent solidification of the residue.

When methanol is distilled off, methanol can be distilled off after directly adding water to the reaction solution, or methanol can be further sufficiently distilled off by adding distilled water to remove some methanol from the reaction solution. You may.

The method of the present invention is economically advantageous because more than 95% of methanol can be recovered, and even when DME is separated by neutralization, methanol, which causes methyl ether of DME enol to be produced as a by-product, is removed. Since it is not present, a decrease in yield can be prevented.

The aqueous solution of sodium salt of DME enol obtained by the present invention can be used as is as a raw material for other reactions, but DME can also be easily isolated from the aqueous solution.

That is, an aqueous solution of sodium salt of DME enol obtained by distilling off methanol is neutralized with hydrochloric acid or sulfuric acid while cooling, and precipitated DME crystals are separated.

Alternatively, a poorly water-soluble organic solvent such as ethylene dichloride is added to an aqueous solution of a sodium salt of DME enol, neutralized with hydrochloric acid or sulfuric acid, and then separated, the organic phase is azeotropically dehydrated, and DME is obtained which precipitates after cooling.

The mother liquor is recycled as an extraction solvent. The amount of organic solvent used varies depending on the type of solvent, but it is usually 1000 to 2000 yd per mole of malonic acid dimethyl ester.
is used.

The present invention will be explained in more detail with reference to Examples below.

Example 1 A reactor with an internal volume of 500 mm was used, and 132 mm of malonic acid dimethyl ester was added to the reactor. of, add 25.0% sodium methylate methanol solution i43.2f and warm, and while keeping the internal temperature at 60°C, menthyl oxide 98%.
1 was added dropwise over about 1 hour.

Next, 172.8 f of a 25.0% sodium methylate methanol solution was added dropwise at the same temperature, and the mixture was refluxed for 1 hour.

Next, the internal temperature was raised to 72°C, 94.0g of methanol was distilled off, and 150f of water! Add water-methanol 16
When 1 g is distilled off, 340 g of DME sodium salt aqueous solution is obtained.
f (214 g as sodium salt of DME enol, yield 97.2%) was obtained.

Transfer this to a 34 container, add 1880f of water, and while stirring under water cooling, 35.5% hydrochloric acid 102.8? was slowly added dropwise, and the precipitated crystals were filtered, washed with 100 g of water, and 435 g of DME wet weight was obtained.

This was dried to obtain 184 g of DME crystals.

m p 101-103°C.

Example 2 340y of a sodium salt aqueous solution of DME enol (2141 as a sodium salt of DME enol, yield: '47.2) obtained by the same operation as in Example 1 was transferred to a reaction vessel 21, and 1200f of ethylene dichloride was added thereto. While stirring at room temperature, 102.8 f of 35.5% hydrochloric acid was added dropwise.

After the completion of the dropwise addition, extraction was carried out with stirring for 1 hour, and the mixture was allowed to stand still for liquid separation.

The organic phase is 100f of water! After washing with water, filtering, and standing to separate the liquids, azeotropic dehydration was performed.

The distilled water was separated, and the organic phase was cooled with ice while stirring to precipitate DME crystals.

The precipitated crystals were filtered and dried with DME168. Obtained OV.

m, p, 101=l O2°C. The ethylene dichloride solution of the tear fluid containing dissolved DME is reused as the extraction solvent.

Example 3 A reactor with an internal volume of 500 d was used, and dimethyl malonate 132. Of, add mesityl oxide 98.01,
25.0% sodium methylate methanol solution 216
．． Of was added little by little.

After refluxing for 1 hour after the dropwise addition, 150v of water was added and distilled under normal pressure until the internal temperature reached 104°C to remove 255g of water-methanol. 213.1' (yield 97.0%) was obtained as the sodium salt.

This sodium salt aqueous solution of DME enol was transferred to a container 21, ethylene dichloride 1201' was added thereto, 102.8f of 35.5% hydrochloric acid was added dropwise with stirring at room temperature, and after the dropwise addition was completed, extraction was carried out with stirring for 1 hour, followed by static separation. did.

The organic phase was washed with 1,001 ml of water, filtered, allowed to stand, and then subjected to azeotropic dehydration.

When the distilled water was separated and the organic phase was cooled on ice while stirring, DME crystals were precipitated.

The precipitated crystals were filtered, dried and treated with DME 174. O
I got f.

m, p, 100-102°C. Dissolved DME 14. The ethylene dichloride solution of P solution containing IV is reused as an extraction solvent.

Claims (1)

[Claims] 1. 4-Methoxy, which is characterized in that water is added to a reaction solution obtained by reacting dimethyl malonic acid ester, mesityl oxide, and a methanol solution of sodium methylate, and then methanol is distilled off. A method for producing an aqueous sodium salt solution of carbonyl-5,5-dimethylcyclohexane-1,3-dioneenol. 2. The manufacturing method according to claim 1, wherein methanol is distilled off at normal pressure.