US3306935A - Trichloroacetic acid dichloroethylidene hydrazide and process therefor - Google Patents

Description

United States Patent 3,306,935 TRICHLOROACETIC ACID DICHLOROETHYLI- DENE HYDRAZIDE AND PROCESS THEREFOR Christ N. Yiannios, North Haven, and Joseph V. Karabinos, Orange, Conn, assignors to Olin Mathieson Chemical Corporation, New Haven, (301111., a corporation of Virginia No Drawing. Filed July 30, 1965, Ser. No. 476,150 4 Claims. (Cl. 260-561) This invention relates to a novel substituted hydrazide, and more specifically it relates to trichloroacetic acid dichloroethylidene hydrazide having the formula:

It has been found that the heretofore unknown hydrazide I can be provided in high yield and purity by the reaction of chloral with hydrazine under anhydrous conditions and in the presence of selected carboxylic acids. The preparation of the hydrazide I is believed to proceed according to the following reaction scheme wherein a chloralhydrazine intermediate II is first formed.

II RCOOH ClaCCHO The preparation of trichloroacetic acid dichloroethylidene hydrazide in accordance with the process disclosed herein is a surprising and unexpected feature of this invention. The reaction of chloral with hydradine has been previously reported, and there is no suggestion that the compound I is provided as a product. For instance, Knopfer in Monatshefte fur chemie, 37, 364 (1916) has disclosed that hydrazine hydrate and chloral hydrate react in glacial acetic acid to provide a five membered heterocyclic compound having two nitrogen atoms in the ring system and six chlorine atoms.

As mentioned in the foregoing discussion, a selected carboxylic acid must be utilized in the process of this invention. The function of this acid is not completely understood, but it apparently reacts with the basic chloralhydrazine prior to the further reaction of a second mole of chloral wherein hydrazide I formation is completed. Thus stoichiometrically the process requires the use of an equimolar amount of the acid relative to the amount of formed chloralhydrazine II. It has been found that carboxylic acids having 1-4 carbon atoms and a dissociation constant of at least 1.0x l0 in water at 25 C. can be successfully utilized in the preparation of the hydrazide I. Particularly useful in this regard are the fatfiy acids such as formic, acetic, propionic and butyric act 5.

The formation of trichloroacetic acid dichloroethylidene hydrazide from the chloralhydrazine intermediate proceeds at a temperature range of about 25 C. to about 80 C. and most advantageously at 40-60 C. Thus generally the process of this invention comprises contacting hydrazine, chloral and the selected carboxylic carboxylic acid together at the aforementioned temperature range to provide the hydrazide I. It is advantageous to utilize an excess amount of carboxylic acid wherein it also functions as a diluent to enhance hydrazide yield, but this is not an essential feature of the process disclosed herein. Upon completion of the reaction, some of the desired hydrazide is obtained immediately in the form of a precipitated solid with the amount depending essentially upon the amount of carboxylic acid diluent employed. The remainder of the desired product is conveniently provided by pouring the reaction mixture into ice water wherein the insoluble trichloroacetic acid dichloroethylidene hydrazide is separated by filtration, centrifugation or similar procedures.

However, the preferred process embodiment comprises forming chloralhydrazine II by reaction of substantially equimolar quantities of chloral and hydrazine prior to introduction of the carboxylic acid and additional chloral into the reaction system. The chloral and hydrazine are conveniently reacted together in an inert diluent such as ether, petroleum ether, benzene, toluene, etc., to provide a solution of the chloralhydrazine. Preferably intermediate II formation is accomplished below 25 C. to minimize degradation of this compound. Then the carbox-ylic acid and additional chloral required to complete the hydrazide preparation are added to the chloralhydrazine solution, and hydrazide I is formed at about 25 C. to about C. Volatile solvents such as ether and petroleum ether can be removed by distillation in this temperature range leaving a reaction mixture which can be treated as disclosed in the foregoing discussion to isolate the desired compound I. When higher boiling solvents such as benzene and toluene are employed, workup is accomplished by pouring the entire reaction mixture into water wherein a two layer system is achieved. The hydrazide is essentially insoluble in water and preferably soluble in benzene or toluene thus affording a ready method of separation upon evaporation of solvent. The hydrazide can 'be recrystallized from solvents such as benzene, toluene and preferably xylenes.

Trichloroacetic acid dichloroethylidene hydrazide is a useful agricultural chemical and has demonstrated utility as a nematocide especially in the control of the root knot nematode. It is particularly valuable as a preplant herbicide wherein it is incorporated in the soil surrounding valuable crops before the crop is planted or simultaneously with the crop planting. Thus, when herbicidal formulations containing the hydrazide I as the active ingredient are applied to the soil area surrounding cotton and corn plants, outstanding control of various harmful Weed species including pigweed, crabgrass, mustard, and ryegrass has been obtained. It has been found that the hydrazide is effective in this application in amounts of as little as 12 pounds per acre although generally it is utilized in amounts of 2-10 pounds per acre.

Although trichloroacetic acid dichloroethylidene hydrazide can be employed in concentrated form as a herbicide, it is more practical to utilize it in a dispersed form admixed with a major amount of a suitable carrier or diluent. A variety of liquid and solid diluents may be employed in the preparation of useful herbicidal formulations containing the hydrazide as the active ingredient. It is preferably applied to the soil in the form of a dust or a powder wherein it is admixed with inert solids such as kaolin, calcium carbonate, talc, Bardens clay, and the like. Generally it is incorporated with such solid carriers as a result of suitable ball milling or grinding operations. A suitable wetting or dispersing agent such as for instance an ethoxylated nonylphenol can be added to these solid formulations to provide wettable powders which are especially suitable for mixing with water to obtain dispersions useful in spraying operations. The hydrazide I can also be applied to the soil 'by spraying operations wherein solutions of the active ingredient in appropriate organic solvents are utilized.

The following example is illustrative of the preparation of trichloroacetic acid dichloroethylidene hydrazide in accordance with this invention.

Example 1 Into a three liter, three-necked flask equipped with air stirrer, dropping funnel, thermometer, water condenser and a nitrogen inlet tube was placed 147 g. (1.0 mole) of anhydrous chloral dissolved in 900 ml. of absolute ether. The reaction fiask was immersed in a salt-ice bath, and the solution was cooled to 5 C. and blanketed with a nitrogen atmosphere. While the etheral chloral solution was stired vigorously, 32 g. (1.0 mole) of anhydrous hydrazine was added dropwise at a rate such that the temperature in the flask was maintained between 5 C. and 3 C. A white powder, the chloral-hydrazine adduct, started precipitating immediately. When the addition of hydrazine was complete, three moles of anhydrous chloral (441 g.) dissolved in 800 ml. of glacial acetic acid were added cautiously and the mixture was stirred for 15 minutes at 5 C. Most of the ether was removed under vacuum. The temperature was allowed to rise gradually to 45 -50 C. at atmospheric pressure while sweeping nitrogen through the flask to remove the traces of ether. During the rise in temperature, a series of color changes were observed from yellow to pink-red to orange and back to yellow. After complete removal of the ether was accomplished, the slurry dissolved to give a clear amber solution. This was stirred at 45 -50 C. for 5 hours. The solution was then allowed to stand at 5 C. overnight. A white crystalline precipitate formed, was collected by filtration, washed three to five times with water and dried under vacuum at 45 -50 C. This product had a melting point of 135 15 C. Yield: 45%. The filtrate was added with agitation to three liters of ice water to give a light yellow precipitate which was subsequently washed with cold water. This material had a melting point of 115130 C. The yield of the combined crude products was 86%. Repetitious recrystallization of either crude material from xylene raised the melting point to 159 160 C. For analytical purposes, a sample of crystallized material was dissolved in Xylene and passed through a silica-gel column. The eluate was allowed to stand and crystals were obtained which had a melting point of 1601 61 C. The following analytical data revealed that trichloroacetic acid dichloroethylidene hydrazide had been obtained in high purity.

AnaZysis.Calcd. for C H CI N O: C, 17.58; H, 1.10; N, 10.60; Cl, 65.10. Found: C, 17.90; H, 1.10; N, 10.45; Cl, 64.50.

Infrared and nuclear magnetic resonance spectra also confirmed that trichloroacetic acid dichloroethylidene hydrazide had been obtained in high purity.

What is claimed is:

1. Trichloroacetic acid dichloroethylidene hydrazide.

2. A process for preparing trichloroacetic acid dichloroethylidene hydrazide which comprises forming chloralhydrazine by the reaction of substantially equimolar amounts of chloral and hydrazine, reacting said chloralhydrazine with chloral and a liquid carboxylic acid at a temperature of about 25 C. to about 80 C., said carboxylic acid having 14 carbon atoms and having a dissociation constant of at least 1.0 1O in water at 25 C.

3. The process of claim 2 wherein acetic acid is employed as the required carboxylic acid.

4. The process of claim 2 wherein a reaction temperature range of 60 C. is utilized.

No references cited.

ALEX MAZEL, Primary Examiner.

I. A. NARCAVAGE, Assistant Examiner.

Claims (2)

1. TRICHLOROACETIC ACID DICHLOROETHYLIDENE HYDRAZIDE.

2. A PROCESS FOR PREPARING TRICHLOROACETIC ACID DICHLOROETHYLIDENE HYDRAZIDE WHICH COMPRISES FORMING CHLORALHYDRAZINE BY THE REACTION OF SUBSTANTIALLY EQUIMOLAR AMOUNTS OF CHORAL AND HYDRAZINE, REACTING SAID CHLORALHYDRAZINE WITH CHLORAL AND A LIQUID CARBOXYLIC ACID AT A TEMPERATURE OF ABOUT 25* C. TO ABOUT 80* C., SAID CARBOXYLIC ACID HAVING 1-4 CARBON ATOMS AND HAVING A DISSOCIATION CONSTANT OF AT LEAST 1.0X10-5 IN WATER AT 25* C.