DE1171896B - Process for the production of dichloroacetaldehyde with a substantially reduced content of monochloroacetaldehyde. - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school KL: C 07 c

German class: 12 ο -7 / 0.3

Number: 1171 896.

File number: F 38020 IV b / 12 ο

Filing date: October 12, 1962

Opening day: June 11, 1964

The invention relates to a process for the production of dichloroacetaldehyde with a reduced content of monochloroacetaldehyde and other impurities from chlorination of acetaldehyde or Paraldehyde.

Dichloroacetaldehyde is used to produce an insecticide, 1,1 - di - (4 - chlorophenyl) - 2,2 - dichloroethane, used. For this process is a dichloroacetaldehyde with a low content of Impurities, especially monochloroacetaldehyde, are desirable in order to have an end product with lighter color Color and good freezing point.

A common process for the preparation of dichloroacetaldehyde is carried out by chlorinating either paraldehyde or acetaldehyde in two successive steps, with the evolution of HCl gas. In the first stage, stoichiometric quantities of chlorine and paraldehyde in the first reaction vessel at a temperature of about 75 are mixed to 8O ⁰ C. The partially chlorinated product is then transferred to a second vessel and subjected there to further chlorination with excess chlorine. The amount of chlorine added is regulated depending on the chlorine uptake by the solution. This can be measured by analyzing the overflowing gas and determining the amount of HCl present.

In addition to this reaction, two side reactions also take place, leading to the formation of monochloroacetaldehyde and trichloroacetaldehyde.

If paraldehyde is used as the starting material, another contamination is obtained Reaction of cyclic paraldehyde with chlorine to form chlorinated cyclic paraldehyde.

One of the main problems raised by this process for the preparation of dichloroacetaldehyde is the large amount of monochloroacetaldehyde formed in the end product. The amount of monochloroacetaldehyde is usually on the order of about 10 percent by weight of the final reaction mixture. A reaction product obtained in this known process, consists of 84.5% dichloroacetaldehyde, 13.2% monochloroacetaldehyde, 2.0% chloral, and 0.3 ° / ₀ chlorinated contaminants. This by-product is particularly unpleasant because it provides an inferior quality of the insecticide mentioned. The removal of the monochloroacetaldehyde from the dichloroacetaldehyde is difficult, since the monochloroacetaldehyde ^{boils only 3 °} C. lower than the dichloroacetaldehyde. Separation by ordinary distillation is therefore impossible.

Process for the production of
Dichloroacetaldehyde with an essential
reduced content of monochloroacetaldehyde

Applicant:

FMC Corporation, New York, N.Y. (V. St. A.)

Representative:

Dr. F. Zumstein,

Dipl.-Chem. Dr. rer. nat. E. Assmann

and Dipl.-Chem. Dr. R. Koenigsberger,

Patent Attorneys, Munich 2, Bräuhausstr. 4th

Named as inventor:

David Daniel Centola, Rockville, Md.,

Nicholas Racsok, Carteret, N. J. (V. St. A.)

Claimed priority:

V. St. v. America October 31, 1961

(148 855)

US Pat. No. 2,947,671 describes the purification of a conventional, technically obtained crude Dichloroacetaldehyde reaction product by distillation with the addition of sulfuric acid or a Toluenesulfonic acid described. Here, the volatility of dichloroacetaldehyde is in proportion changed to monochloroacetaldehyde so that a separation and purification of the dichloroacetaldehyde is made possible.

In contrast, according to the process of the invention, a very pure dichloroacetaldehyde is obtained from the outset obtained, which contains so little monochloroacetaldehyde that no more special separation is required.

In "Industrial and Engineering Chemistry", 39, 1947, a process for the depolymerization of trioxane for the production of formaldehyde using toluenesulfonic acid as a depolymerization catalyst described. From this publication, however, there is no indication that this Sulphonic acid is the selective chlorination of acetaldehyde or paraldehyde to produce only one Could catalyze small amounts of monochloroacetaldehyde containing dichloroacetaldehyde.

According to the invention, dichloroacetaldehyde is obtained with a significantly reduced content of monochloro

409 599B25

acetaldehyde by using acetaldehyde or paraldehyde or one of acetaldehyde or paraldehyde obtained in the presence or absence of the sulfonic acids designated below by partial chlorination Reaction mixture in the presence of about 0.5 to about 2.0 percent by weight of benzenesulfonic acid, toluenesulfonic acid or methanesulfonic acid, optionally in the presence of about 0.1 percent by weight Antimony trichloride, reacts with chlorine at about 67 to 80 ° C.

The selective catalytic effect of these sulfonic acid catalysts is extremely surprising. These catalysts selectively catalyze the conversion of monochloroacetaldehyde to dichloroacetaldehyde without to catalyze the conversion of dichloroacetaldehyde to trichloroacetaldehyde. Therefore, all monochloroacetaldehyde, which is present in the reaction mixture, selectively converted into dichloroacetaldehyde. In addition, these catalysts catalyze when using paraldehyde as a starting material the conversion of paraldehyde to acetaldehyde and thereby complete the formation of chlorinated paraldehyde by-products the end.

The process of the invention is preferably carried out in two stages, starting from a reaction mixture obtained from acetaldehyde or paraldehyde in the presence or absence of the sulfonic acid catalysts mentioned by partial chlorination. This enables better chlorination. In general, paraldehyde is preferred as the starting material because it has a higher boiling point than acetaldehyde and can therefore be kept at higher temperatures under normal pressure. The paraldehyde is added to the first reaction vessel (pre-chlorination), after which chlorine gas is bubbled through the liquid. The gaseous chlorine is usually added in stoichiometric amounts and HCl and unreacted chlorine gas are withdrawn from the top. Since chlorination is an exothermic reaction, a cooling device is used to maintain the mixture at temperatures between 75 and 8O ⁰ C. The partially chlorinated product is then fed to a second stage where excess chlorine is bubbled through the solution until the conversion to dichloroacetaldehyde is complete.

The catalyst is added to one or both reaction vessels and is easiest to combine brought into the reaction vessels with the feed stream. The sulfonic acid catalyst is used in quantities from about 0.5 to about 2.0 weight percent added. At a concentration of around 2%, one occurs Trapping effect, so that amounts of sulfonic acid above 2.0% do not give any noticeable improvement.

The sulfonic acids mentioned can be used alone, but still give better results obtained in the presence of small amounts of antimony trichloride, d. H. on the order of about 0.1 percent by weight. The combination of 1% toluenesulfonic acid and 0.1% antimony trichloride enables a reduction in the monochloroacetaldehyde content in the dichloroacetaldehyde product to less than 0.5 percent by weight. It must be noted, however, that antimony trichloride is sufficient when used catalyzes the reaction of dichloroacetaldehyde to trichloroacetaldehyde in large quantities. Therefore, the The amount of antimony trichloride used should never be more than 0.5 percent by weight.

The process according to the invention can be carried out either continuously or batchwise. The continuous mode of operation is preferred because it gives better yields with plants of the same size enables. In the continuous process, the catalyst is continuously due to periodic Additives added to the feed streams.

The relationship between the weight of the catalyst added and the content shown below of monochloroacetaldehyde in the end product shows the effect of adding these sulfonic acid catalysts in increasing quantities. The sulfonic acid added in this case was p-toluenesulfonic acid.

° / ₀ of added catalyst Content of
Monochloroacetaldehyde
in percent by weight 0.5
1.0
2.0 5.8
3.3
1.7

In the case of a mixture of 1% p-toluenesulfonic acid and 0.1% antimony trichloride, the monochloroacetaldehyde in the final product was 0.42%. The following examples illustrate the invention.

example 1

There were 200 g of a reaction mixture consisting of Erststufenchlorierung by reaction of chlorine with paraldehyde in a molar ratio of about greater than 3: 1 were obtained at 75 to 8O ⁰ C without a catalyst and 83% of dichloroacetaldehyde, 14 ° / ₀ monochloroacetaldehyde and 2% chloral contained, and 2 g of p-toluenesulfonic acid placed in a 300-ml three-necked flask fitted with magnetic stirrer, cold trap (-30 to -40 ⁰ C), thermometer and gas inlet tube. The p-toluenesulfonic acid constituted 1 percent by weight of the reaction mixture. The flask was immersed in a water bath maintained at 70 to 71 ^{° C.} Once the mixture had reached 70 ° C, was at a rate of 0.79 g / min. (250 ml / min.) Introduced chlorine gas and kept the temperature at 69 to 70 ° C. Samples for vapor phase chromatographic analysis were taken at certain intervals. The chlorination lasted 5 hours and the weight gain of the solution was 15.8 g. Analysis of the end product showed 3.7% monochloroacetaldehyde, 93.1% dichloroacetaldehyde and 3.1% chloral.

Example 2

0.75 g of p-toluenesulfonic acid and 0.075 g of antimony trichloride were added to 75.0 g of a reaction product mixture obtained from a first stage chlorination as in Example I and containing 83% dichloroacetaldehyde, 14% monochloroacetaldehyde and 2% chloral. The mixture obtained was placed in a 300 ml three-necked flask equipped with a magnetic stirrer, cold trap (-30 to -4O ⁰ C), thermometer, chlorine gas inlet tube and paraldehyde inlet tube. The flask was placed in a water bath kept ^{at 70 to 71 ° C.} Once the mixture had reached 7O ⁰ C, paraldehyde was fed at a rate of 0.67 g / min continuously. At the same time, at a rate of 1.95 g / min. (624 ml / min.) Continuously introduced chlorine gas. The temperature fluctuated

5 6

67-71 ⁰ C. The paraldehyde 0.42% monochloroacetaldehyde, 94.98% flask was added 2 hours the mixture. l ^x / ₂ hours after containing dichloroacetaldehyde and 4.60% chloral. At the end of the addition of paraldehyde, the addition of chlorine was reduced to 0.79 g / min. (250 ml / min.) Reduced comparison test and the chlorination continued for a further 3 hours. 5

An analysis of the end product then carried out as a control for the determination of the monochlorine showed that it consisted of 7.37% monochloroacetaldehyde, amount of acetaldehyde, 89.02% dichloroacetaladehyde and 3.61% chloral when the chlorination was carried out in the absence of the catalyst selected according to the invention. After the chlorination further 4 hours lysators obtained, a second batch at 67 to 7O ⁰ C and chlorine addition rate io was performed. This control was run from 0.79 g / min. (250 ml / min.), Leads that 200 g of a first-stage chlorination product was obtained, the 3.34% monochloro-obtained product mixture, the 83% dichloroacetaldehyde, 90.55% dichloroacetaldehyde and 6.10% acetaldehyde, 14% monochloroacetaldehyde and 2% chloral. Chloral contained, were placed in a 300 ml three-necked flask R ei ς η ie 1 3 ¹ S, which was operated with a magnetic stirrer, a ^P cold trap (-30 to -4O ⁰ C), thermometer and gas

75.0 g of a dichloroacetaldehyde product mixture was equipped with an inlet tube. No catalyst was added to the flask from a first stage chlorination vessel as in Example 1. The solution was heated to the 83% dichloroacetaldehyde, 14% monochloroacet- 7O ⁰ C in a water bath and the chlorination aldehyde and 2% chloral contained, and 0.75 g ₂ o started. The chlorine gas was introduced into a 300 ml three-necked speed of 0.79 g / min with a speed toluenesulfonic acid, and the flask was brought to the temperature, which was kept ^{at 70 ° C. with a magnetic stirrer, one of which was during the chlorination.} Cold trap (-30 to -40 ° C), thermometer, chlorine gas - After 2Va hours of chlorination, a feed pipe and paraldehyde feed pipe were fitted - a sample of the composition that was vapor-phase treated. The flask was subjected to a matographischen at 70 to 71 ⁰ C 25 analysis. The final included water bath is brought. Once the mixture composition showed 13.2% monochloroacetaldehyde, had reached 7O ⁰ C, paraldehyde was continuously dichloroacetaldehyde 84.5% and 2.3% chloral, at a rate of 0.67 g / min. 2 hours

long fed. At the same time, example 5

Chlorine gas at a rate of 1.95 g / min. 30 200 g of a product mix that is

(624 ml / min.) Added. The temperature fluctuated in the stage chlorination as obtained in Example 1

between 57 and 69 ⁰ C. The chlorination was further and the 83% dichloroacetaldehyde, 14% mono-

Continued 3 hours after the paraldehyde addition contained chloroacetaldehyde and 2% chloral

was finished, 75 g of this material was taken and added to 0.2 g of methanesulfonic acid. The mixture

and used as an approach for the following day. ₃₅ was placed in a 300 ml three neck round bottom flask,

On the following three days, a magnetic stirrer, a cold trap (-30 to

the following approaches using the same -4O ⁰ C), thermometer and gas inlet pipe-

Paraldehyde feed rate and chlorine was armed. The flask was in a at 70 to 71 ⁰ C

Additional speed executed. Initially, held water baths were immersed. As soon as the mini

For each of these approaches 0.75 g of p-toluenesulfonic acid ₄₀ Research 70 ° C was reached, the chlorine gas was treated with a

admitted. On the fourth day, the entire product was introduced at a rate of 0.79 g / min.

of the three previous approaches mixed with one another temperature the reactants was at 7O ⁰ C

and chlorinated. The chlorination was kept in the presence. After _a chlorination time of 5V a hour

carried out by 2.3 g of p-toluenesulfonic acid. The chlorine is a sample for vapor phase chromatography

The additional speed was 1.95 g / min. (624 ml / min.), 45 analysis taken. The analysis result shows that

and chlorination was carried out for 5 hours. the mixture of the reaction products 2.02% mono-

The product was analyzed and a content of chloroacetaldehyde, 94.54% and dichloroacetaldehyde

Contained 3.83% monochloroacetaldehyde, 93.23% dichloroacetate-3.45% chloral.

aldehyde and 2.94% chloral found.

B e1s ρ ie I 6

B e i s ρ i e 1 4 200 g of a product mixture, which in an initial

200 g of a reaction product mixture from a stage chlorination as in Example 1 have been obtained

First stage chlorination as in Example 1, which was 83% and 83% dichloroacetaldehyde, 14% mono-

Dichloroacetaldehyde containing 14% monochloroacetaldehyde and chloroacetaldehyde and 2% chloral were added to

Containing 2% chloral, 0.2 g of benzenesulfonic acid were added to 0.2 g of antimony tri-55. The mix was

chloride and 2 g of p-toluenesulfonic acid were added. Put them in a 300 ml three-necked flask that comes with

Mixture was poured into a 300 ml three-necked flask, a magnetic stirrer, a cold trap (-30 to -40 ° C)

given with a magnetic stirrer, a cold trap, a magnetic stirrer, a cold trap (-30 to

(-30 to -40 ° C), thermometer and gas inlet -4O ⁰ C), thermometer and gas inlet pipe made of

pipe was provided. The flask was set up in a 60 position. The flask was in a at 70 bis

70 to 71 ⁰ C held water bath immersed. 71 ⁰ C held water bath immersed. As soon as the

As soon as the mixture had reached 70 ^° C., the mixture had reached 70 ^° C., chlorine gas was added

a speed of 0.79 g / min. ' Chlorine gas introduced at a rate of 0.79 g / min,

initiated. The temperature of the reactants The temperature of the reactants was at

was maintained at 7O ⁰ C. After a 2 hour 65 70 ⁰ C held. After an SVa hour chlorination time

chlorination became vapor phase chromatography, a sample became vapor phase chromatography

graphical analysis taken a sample. Taken from the see analysis. The analysis result

Analysis results showed that the products shows that the mixture of reaction products is 2.0%

Contained monochloroacetaldehyde, 94.6% dichloroacetaldehyde and 3.4% chloral.

Example 7

200 g of a product mixture which had been obtained in a first-stage chlorination as in Example 1 and which contained 83% dichloroacetaldehyde, 14% monochloroacetaldehyde and 2% chloral were added to 0.2 g of m-toluenesulphonic acid. The mixture was placed in a 300-ml three-necked round bottom flask equipped with a magnetic stirrer, a cold trap (-30 to -40 ⁰ C), thermometer and gas inlet tube. The flask was immersed in a water bath kept at 70 to 71 ^{° C.} As soon as the mixture had reached 70 ^° C., chlorine gas was introduced at a rate of 0.79 g / min. The temperature of the reactant was maintained at 7O ⁰ C. After a _{chlorination time of 5V 2} hours, a sample was taken for analysis by vapor phase chromatography. The analysis result shows that the mixture of the reaction products 2.1% mono- S. chloroacetaldehyde, 94.5%
Contained 3.4% chloral.

Dichloroacetaldehyde and

Claims (1)

Claim: Process for the production of dichloroacetaldehyde with a significantly reduced content art Monochloroacetaldehyde, characterized in that acetaldehyde or paraldehyde is used or one of acetaldehyde or paraldehyde in the presence or absence of those designated below Sulfonic acids obtained by partial chlorination reaction mixture in the presence of about 0.5 to about 2.0 percent by weight of benzenesulfonic acid, toluenesulfonic acid or methanesulfonic acid, optionally in the presence of about 0.1 weight percent antimony trichloride, at about 67 to 80 ° C reacts with chlorine. Considered publications:
U.S. Patent No. 2,947,671;
Industrial and Engineering Chemistry, 39,
to 977. 1947, 409 599/325 6. 64 Bundesdnickerd Berlin