US3253900A - Herbicidal composition containing polychlorotoluyl chloride - Google Patents

Description

United States Patent 3,253,900 HERBICIDAL COMPOSITION CONTAINING POLYCHLOROTOLUYL CHLORIDE Jack S. Newcomer, Wilson, Edward D. Wei], Lewiston, and Edwin Dorfman, Grand Island, N.Y., assiguors'to Hooker Chemical Corporation, Niagara Falls, N.Y., a corporation of New York No Drawing. Filed May 15, 1961, Ser. No. 109,881

- 1 Claim. (Cl. 712.3)

This application is a continuation-in-part of Serial Number 714,965, filed in the United States Patent Oflice, February 13, 1958, now abandoned.

This application describes a novel class of chlorinated aromatic compounds useful as herbicides and chemical intermediates for the preparation of other herbicides and pesticides.

More particularly, this invention relates to herbicidal toluyl chlorides having at least one chlorine on the aromatic ring and at least one chlorine on the side chain,

preferably having the structure:

wherein m is a positive integer from one to four and n is a positive integer from one to tWo.

The following acid chlorides are illustrative examples of the compounds of this invention:

a,2-dichloro-m-toluic,

a,5-dichloro-m-toluic, u,6-dichloro-m-to1uic, u,2,4-trichlor0-m-toluic, u,2,5-trichloro-rn-toluic, m,2,6-trichloro-m-toluic, ,4,S-trichloro-m-toluic, a,4,6-trichloro-m-toluic, a,5,6-trichloro-rn-toluic, v 04,2,4,S-tetrachloro-m-toluic, a,2,4,G-tetrachloro-m-toluic, ,2,5,6-tetrachloro-m-toluic, 41,4,5,6-tetrachloro-m-toluic, cc,oc,2-t1'iChlOIO-m-t0ll1i0, a,a,4-trichloro-m-toluic, a,ot,5-tIiChlO1'O-II1-i0l1li0, a,a,6-trichloro-m-toluic, a,ot,2,4-t6iI3ChlOIO-II1-i0llli6, a,a,2,S-tetrachloro-m-toluic, a,a,2,6-tetrach1oro-m-toluic, a,u,4,S-tetrachloro-m-toluic, u,a,4,6-tetrachloro-m-toluic, a,a,5,6-tet11achloro-rn-toluic, a, x,2,4,5-pentachloro-m-toluic, u,a,2,4,6-pentachlor0-m-toluic, a, x,2,5,6-pentachloro-m-toluic, u,u,4,5,6-pentachloro-m-toluic, a,a,2,4,5,6-pentachloro-m-toluic, a,a,a,2-tetrachloro-m-to1uic, a,a,u,4-tetra-chloro-m-toluic, 12,04,a,S-tetrachloro-m-toluic, a,a,a,6-tetrachloro-m-toluic, a,a,a,2,S-pentachloro-rn-toluic, a, z,u,2,6-pentachloro-m-toluic, u,a,a,2,5,6-hexachloro-m-toluic and a,a,u,4,5,6-hexachloro-m-toluic,

3,253,900 Patented May 31, 1966 3 ,5 ,a,a-tetrachloro-o-toluic, 3,6,u,a-tetrachloro-o-toluic,

4,5 ,a,a-tetrachloro-o-toluic, 4,6,a,a-tetrach1oro-o-toluic,

5 ,6,u,a-tetrachloro-o-toluic, 3,4,5,a,a-pentachloro-o-toluic, 3,4,6,a,a-pentachloro-o-toluic, 3 ,5 ,6,a,a-pentachloro-o-toluic, 4,5,6,a,a-pentachloro-o-toluic, 3,4,5 ,6,a,u-hexachloro-o-toluic, 3 ,a,a,u-tetrachloro-o-toluic, 4,a,a,a-tetrachloro-o-toluic,

5 ,a,a,a-tetrachloro-o-toluic, 6,a,u,m-tetrachloro-o-toluic, 3,4,a,ot,a-pentachloro-o-toluic, 3,5,a,a,a-pentachloro-o-toluic, 3,6,a,u,ot-pentachloro-o-toluic, 4,5,ot,a,a-pentachloro-o-toluic, 4, 6,a,a,a-pentachloro-o-toluic, 5,6,a,u,u-pentachloro-o-toluic, 3,4,5 ,Ot,06,0t-i16XflCh1OI'O-O-t0'llll6, 4,5,6,a,a,ot-hexachloro-o-toluic, 3,4,5 ,6,a,a,a-heptachloro-o-toluic, 2,u-dichloro-p-toluic, 3,0c-diChlOI0-P-t0llli0,

2,3 ,oc-tl'iChIOIO-p-tOlLliC, 2,5,a-tricl1loro-p-to1uic, 2,6,ot-trichloro-p-toluic,

- 3,5,0C-tI'iChIOI'O-P-tOlUiC,

2,3,5,ot-tetrachloro-p-toluic, 2,3,6,a-tetrachloro-p-toluic, 2,3,5,6,a-pentachloro-p-toluic, 2,u,a-trichloro-p-toluic, 3,a,a-trichloro-p-toluic,

2,3 ,a,a-tetrachloro-p-toluic,

2,5 ,a,ot-tetrachloro-p-toluic, 2,6,0t,OL-tBtI'aChiOI'O-P-tOhliC,

3,5 ,a,a-tetrachloro-p-toluic, 2,3,5 ,a,u-pentachloro-p-toluic, 2,3 ,6,a,a-pentachloro-p-toluie, 2,3,5,6,a,a-hexachloro-p-toluic, 2,0t,a,a-tetrachloro-p-toluic, 3,a,a,a-tetrachloro-p-toluic,

3 ,5 ,a,a,a-pentachloro-p-tolu-ic, 2,6,u,a,a-pentachloro-p-toluic, 2,3,5,a,a,u-hexachloro-p-toluic, 2,3 ,6,a,a,a-hexachloro-p-toluic, 2,3,5,a,a,a-heptachloro-p-toluic acid chlorides.

Although all of the above compounds are herbicidal the preferred embodiment of the compositions of this invention because of ease of preparation, availability and the like are those compositions having a total of from four to seven chlorine atoms.

While there is no paucity of herbicides per se, there is a real need for low-volatility, low drift herbicides which possess a greater margin of safety in respect to desirable plant species. For example, herbicides such as 2,4-D and 2,4,5-T frequently damage crops on the peripheral portions of treated areas because of spray drift and volatility. This tendency is so Well recognized that the use of 2,4-D and its derivatives are prohibited or restricted in many crop areas. The reason for the damage is the extreme phytotoxicity of 2,4-D herbicidal products, particularly against 'broadleaf plants, coupled with the tendency to drift. Thus, even though the rates of the herbicides applied is less than a killing application, there is suflicient concentration of herbicide to cause undesirable hormonal effects such as twisting, leaf area repression and wilting.

The compositions of this invention in contrast have good phytotoxicity toward broadleaf and grassy plants yet are much safer to use.

Another important and desirable attribute that the compositions of this invention possess over the prior art is the rapid dissipation of their phytotoxicity in the soil. This means that shortly after the herbicide has been applied and exerted its phytotoxic effect against the weed species treated, the compounds break down in some manner so that no toxic residue presists in the soil to damage followup and subsequent crops. This offers the obvious economic advantage of allowing full use of high value farmland rather than allowing to remain fallow. No reason or mechanism is advanced why this rather ephemeral phytotoxicity is found in these compounds, when toxic residues of many related structures persist in the soil for periods of time ranging from several months to a year or more in extreme cases. Thus, many commercial herbicides such as herbicidal chlorates, the chlorinated benzoics, and the related ring chlorinated toluic acids leave long term toxic residues in the soil making the planting of sequential crops risky or impossible.

In addition to their herbicidal utility, the compounds of the invention not only have utility as herbicides but also are valuable as chemical intermediates. By reaction with ammonia, N-alkyl amines, N,N-dialkylamines, and anilines, they yield new amides and anilides having biocidal insect repellent herbicidal utility. The amides bearing one or two chlorines on the a-position can be further reacted with 0,0-dimethyl phosphorodithiolate salts and 0,0-diethyl phosphorodithiolate salts to produce useful insecticides and miticides of the structure:

(iJONR R where m is as ,above, and where R and R are hydrogen, alkyl or aryl, and y is one or two.

An additional advantage of the novel method of this invention is that it lends itself to the use of the toxicant in various grades of purity ranging from the highly purified oil or crystalline product to a technical crude. Furthermore, these herbicidal compositions offer the advantage of eompatability with a host of other herbicides including the triand tetrachlorophenylacetic acids and 2,4-D and other herbicidal phenoxy aliphatic acids and esters, simazine and other herbicidal triazines, monuron, fenuron, diuron, and other herbicidal ureas, petroleum oils, hexachlorocyclopentadiene, pentachlorophenol, dinitro-o-alkylphenols, glycol, trichloroacetates, 2,2-dichloropropionates, with insecticides such as benzene hexaehloride and chlordane, and with various adjuvants and diluents Well known to the art. Thus, these herbicides may be used by themselves or made the subject of liquid or solid formulations ranging from the very simple to the most complex. For example, if it is desired these compositions may be made the subject of a liquid formulation by diluting, dispersing, dissolving or emulsifying with a surface active adjuvant or combination of these adjuvants in solvents such as petroleum hydrocarbons, ketones, esters or combinations thereof. Or alternatively, the novel herbicides may be made up as solid formulations of powders, dusts, wettable powders, granules and pellets using solid diluents such as tales, clays, flours, starches, diatomaceous earths, mica, alkaline earth limes, carbonates and phosphates either finely divided, granular or pelleted in form. Unlike aliphatic and some aromatic acid chlorides, the

compounds of the invention are relatively stable to water and consequently formulations of these compounds can be dispersed in water for spraying without fear of decomposition.

These solid and liquid formulations facilitate handling and application and sometimes enhance herbicidal activity to more than an additive degree.

Solutions of the compounds of the invention in mineral oils, kerosene, diesel oils, Weed oils, and the like are particularly effective, giving rapid and thorough kill of mixed weed populations at rates and costs much lower than would be required in using either component alone. A major advantage of the compounds of the invention over related acids and amides is their high solubility in oils, which permits their use as herbicidal oil fortifiers The liquid compositions, whether solutions or dispersions of the active agents in a liquid solvent and also the wettable powder or dust compositions of this invention may contain as a conditioning agent one or more surface active agents in amounts suflicient to render the composition readily dispersable in water. By the term surface active agents are included wetting agents, dispersing agents, emulsifying agents and the like. A satisfactory but not complete list of such agents is set forth in an article in Soap and Chemical Specialties, vol. 31, No. 7, pages 6l; No. 8; pages 48-61; No. 9, pages 52-67, and No. 10, pages 38 (67), 1955. Other sources of adjuvant materials is set forth in Bulletin E-607 of the Bureau of Entomology and Plant Quarantine of the United States Department of Agriculture. Polyoxyethyl esters and ethers are particularly efiicaceous emulsifiers for these compositions.

While the manner and method of application of the inventive compositions is varied and largely dependent upon the climatic conditions, crop treated, the Weeds to be eradicated, the equipment available and the convenience of the user, a preferred embodiment of this invention is to apply these herbicides as a spray after making them up as a liquid formulation comprised of several times their weight of petroleum hydrocarbon solvents and oils such as xylene with small quantities of an emulsifier such as a commercial polyoxyethylene ether and a surfactant such as alkylaryl sulfonate mixture. This type of mixture is emulsified with Water and sprayed on the weed population growing amidst the desired crop or other area where weed growth is not desired. Or alternatively, these compositions may be applied as a solid formulation directly to the ground.

The rate of application cannot be precisely stated due to varying degree of resistance possessed by the Weed species and crop, the stage of weed and crop growth, the soil type and climatic conditions, but in general, the rates will be at least one-quarter of a pound of herbicide per acre and for reasons of cost will seldom exceed one hundred pounds per acre With the preferred range falling within one-half to fifty pounds per acre. Where the weeds are in an early stage of growth, they being more susceptible, will frequently respond to the rates from onehalf to four pounds per acre while older weeds or weeds that are to be totally eradicated from ornamental beds or turf may require rates in excess of four pounds per acre. In those instances Where the Weed population has been allowed to accumulate unchecked or Where mature plants are encountered, applications of up to fifty and even beyond this rate may be required. For eradication of deeply-rooted herbicide-resistant perennial weeds such as field bindweed, rates of ten to one hundred pounds are found best. In oil sprays, concentrations of 0.1 to ten percent of the toxicant in the oil are preferred, the oil being sprayed at the rate of ten to two hundred gallons per acre.

The compounds of the invention may be synthesized by a number of routes, including the following:

A. Side chain chlorination of ring-chlorinated toluyl chlorides or toluic acids.

(|3OX(Clor OH) COX This reaction is ordinarily accomplished by passing C1 gas, liquid C1 or sulfuryl chloride into the liquid compound to be chlorinated or a solution thereof in an inert chlorination solvent such as carbon tetrachloride, employing light as catalyst or employing catalytic amounts of a peroxide such as benzoyl peroxide as catalyst. Suitable temperatures are from minus seventy degrees (convenient where liquid chlorine is employed), to plus two hundred and twenty degrees. At higher temperatures, chlorinolysis of the COX group and/ or the CH ,,Cl group may be a troublesome side reaction. Where the acid is thus produced, it is converted to the chloride by heating With at least one mole of thionyl chloride, PCl or benzotrichloride.

B. Ring chlorination of side chain chlorinated toluyl chlorides or toluic acids.

COX(Clor OH) This reaction is accomplished generally by passing C1 gas or SO CI into the liquid reactant or solution of the reactant in an inert chlorination solvent such as carbon tetrachloride employing a Lewis acid as a catalyst, for example, a few percent or less of FeCl SbCl SnCl TiCl ICl MoCl BF AlCl or AlCl .S Cl Temperatures of from zero degrees centigrade to one hundred and fifty degrees are preferred, higher temperatures may cause side chain chlorination or chlorinolysis, lower temperatures cause sluggish reaction. The acid chloride (X=Cl) is preferred in these reactions. Where the acid is employed, HOCl or NaOCl may be used as ringchlorination reagent in aqueous solution at zero degrees to one hundred degrees centigrade and pH two to seven. Where the acid is thus produced it is converted to the chloride by refluxing with an excess of thionyl chloride.

C. Chlorination of xylenes on the ring and on the side chain, until at least one side chain bears three chlorine atoms, then hydrolysis of the trichloromethyl group by at least one molar equivalent of water to produce a COCl group.

COX

(two steps) 012 (C11 4): Clm

Cl", C 11 01 This reaction is conveniently accomplished by passing C1 into xylene under the conditions for ring chlorination (Lewis acid catalyst), removing the catalyst (by distillation or washing with water), when the desired level of ring chlorination has been reached, then passing C1 under photochemical or free radical catalysis until the desired level of side chain chlorination has been reached, and until the molecule has at least one CCl group. The other CH ,,Cl group will generally then be a --CHC1 or a CCl group.

Reacting one mole of water with this intermediate at about fifty to two hundred and fifty degrees centigrade in the presence of an acid catalyst such as H 50 Zncl or FeCl will yield the COCl group, by hydrolysis of the CCl A variation of this route, to prepare those compounds of the invention where n=1, is to chlorinate the ringchlorinated xylenes under side-chain chlorination conditions as above described, until one methyl group bears one chlorine atom and the other methyl group bears two chlorine atoms, then to hydrolyze under acid catalyzed conditions as above described, which leaves the CH CI group intact and converts the CHC1 group to CHO. The CHO group then reacts preferentially with chlorine under photochemical catalysis to form the COCI group.

The following examples are intended to illustrate the workings of this invention including such facets as the preparation of the herbicidal compositions, their formulation as herbicidal agents, and the testing results obtained using them.

Example ].Preparali0n of mixed isomers of ring-dichlorinated side chain monoand dichlorinated o-toluyl chloride Five parts of o-toluic acid and ten parts of acetic acid were dissolved in two hundred parts of five percent aqueous sodium hypochlorite and allowed to stand at room temperature for 3.5 hours, then acidified with hydrochloric acid to pH two and filtered. Seven parts of white solid was obtained, having a neutralization equivalent of two hundred and two (theory for d-ichloro-o-toluic acid, two hundred and five). this product with refluxing O.1-N KOH in methanol caused no release of chloride ion, proving the chlorine atoms to be on the ring. Infrared evidence showed the mixture to contain substantial 3,6-and 4,5-dichloro-0- toluic acid, by comparison with authentic samples.

Dichloro-o-toluyl chloride was prepared from this mixed dichloro-o-toluic acid by refluxing for one day with five parts of thionyl chloride followed by distillation to obtain the fraction boiling at one hundred and twenty to one hundred and forty-two degrees centigrade (eight mm.), which had the correct analysis for dichloro-otoluyl chloride.

This intermediate was treated with chlorine gas at ninety to one hundred and five degrees under illumination by a four hundred watt mercury vapor lamp until one molar equivalent of hydrogen chloride was evolved. The product was a colorless liquid, having the proper analysis for a trichlorotoluyl chloride having one chlorine atom on the methyl side chain.

Analysis.-Calcd. for C H CI O: Cl (total), 55.1 percent; Cl (hydrolyzable by KOH), 27.5 percent. Found: Cl (total), 54.1 percent; Cl (hydrolyzable by KOH), 27.4 percent.

Continuance of the chlorination until a total of two molar equivalents of hydrogen chloride were evolved gave a viscous colorless liquid having an analysis approximating to that for tetrachloro-o-t-oluyl chloride having two chlorine atoms on the side chain.

Analysis.Calcd. for C H Cl O: Cl (total), 60.8 percent; Cl (hydrolyzable), 36.4 percent. Found: C1 (total), 58.0 percent; Cl (hydrolyzable), 33.6 percent.

Example 2 Mixed dichloro-m-xylene was made by passing C1 into three hundred and eighteen parts of m-xylene containing 0.3 percent ferric chloride at thirty-seven to forty-two degrees centigrade until one hundred and eighty-two parts of hydrogen chloride evolved. The crude product was then fractionated at ten mm., and the fraction boiling at ninety to one hundred and ten degrees centigrade taken as dichloro-m-xylene. Chromatographic analysis shows this to be a mixture of 4,5-, 4,6-, 2,4-, 2,5- and 5,6-isomers.'

Chlorine gas was passed into 88.5 parts of this dichlorom-xylene at one hundred to one hundred and seventy degrees under irradiation by a four hundred watt mercury vapor lamp until ninety parts of hydrogen chloride were Treatment of asmall sample of given off. The viscous syrup which remained had the m-xylene (P and Q indicate ring positions).

Approximately fixe percent by weight of concentrated gen chloride gas is evolved and no further weight uptake occurred, the product is assumed to be the desired, or,oc,o,oc',a',oc',4-hpta(;h1OIO m xylene. To this intermediate is added five percent by weight of concentrated sulfuric acid was added to this intermediate, then water sulfuric acid and the mixture stirred at one hundred and was added dropwise at One hundred and twenty degrees twenty-five to one hundred and forty degrees, While a with stirring, until one molar equivalent of hydrogen one molar equivalent of water is added dropwise over chloride was evolved. This required about one molar two hours, causing the evolution of two molar equivalents equivalent of water. The crude product was fractionated of hydrogen chloride. The crude product is Washed with to obtain P,Q,e,a-tetrachloro-m-toluyl chloride, boiling ice water to remove the sulfuric acid and then fractionalat one hundred and sixty to one hundred and seventyly distilled at reduced pressure. five degrees (2.5 mm.). The fraction boiling at one hundred and' thirty to one Example 3.Preparati0n 0f or,2,3,5,6-pentachZora-p-toluyl g i g and 2 5 fi g 1 'g ig as the chloride and u,a,2,3,5,6-hexachl0r0-p-t0luyl chloride es'lre "f" rac ro'm ouy c u a waxy colorless semi-solid at room temperature. A solutwn conslstlng of 154-5 parts of y y chlo- Analysis.-Calcd. for C H OCI 01, 60.7 percent. ride, two parts of iodine and two parts of FeCl is heated F d: C1, 59.5 percent. to ninety degrees Centigrade. At this temperature chlorine gas is introduced. The reaction temperature is raised Example 5.Preparati0n of 0c,oc,oL,2,5-p@nftZC/ZIOIO-pduring the chlorination to one hundred and fifty degrees toluyl chloride f g f i g gfi fi gg g g g' Chlorine gas was passed into 2,5-dichloro-p-xylene at an fi l g s j g removine one hundred and fifty to one hundred and ninety degrees i d e g i agig 2 t h mired under illumination by an ultraviolet lamp until no further t e t pr fi d g ht 2 Fees Gem hydrogen chloride evolution occurred. The product, rel 1 5 a d at a Selig f standfin 0 crystallized from benzene-ligroin mixture, melted at one 2 0C1 cl 60 0 hundred and eighty degrees and had the correct chlorine F g fg E a t 8 3 p and hydrolyzable chlorine analysis for the expected p 0L,rx,or,oc',ot',oc',2,5 octachloro p xylene. This product One hundred and forty-six parts of 2,3,5,6-tetrachlorot l 1 hlo i heated to one hundred and fort to melted at 198.5 to 199.5 degrees centigrade. 5' E i ssixt degrees cemi fade ex osed 3 an A mixture of one hundred and ninety parts of this a? i as chfinrinafion (fatal 5 aseous octachloro-p-xylene, one hundred and ninety parts of f i duced until 18?, arts i ch1o trichlorobenzene as solvent, and ten parts of concentrated 1S i A viscous 5 roduc: is ibtained sulfuric acid was heated to one hundred and twenty to g ts to semisolid one hundred and thirty degrees and stirred, whereupon W if z for cl 0 ercent nine parts of water was added dropwise over several hours, F0 6 h 8 2 p causing evolution of thirty-six parts of hydrogen chlo- Ep of h com ound obained from Ste ride. The product was then washed with water and frac- 2 E i pa h d d a dpfort to 8 hi ndred g tionally distilled, the fraction boiling at one hundred and Z 0 z an uilltraviolet ht as the sixty-five to one hundred and eighty-two degrees (seven zf i i i f chlorine is introgduced mm.), being collected as the desired a,u,a,2,5-penta- 5. g a i en chloride evolves A colorless chloro-p-toluyl chloride. This colorless material, which o g which on Stow Sets to a wax was not further purified, solidified to a waxy solid and 3 9 15 galcd f C IjIOCI i 69 0 meant was shown to be the desired acid chloride by the fact F "g 6 Ht 8 P that upon heating with several parts by weight of sodium oun p Ce carbonate in methanol, one molar equivalent of chloride Example 4.--a,a,a,4-letrachlloro-m-toluyl chloride and ion was released with formation of methyl oc,oc,oc,2,5-

u,oL,0t,4-t l'rL1ChlOlO-m-[OlbliC acid pentachloro-p-toluate.

One hundred parts by weight of 4-chloro-m-xylene is Exam [6 6 heated to one hundred and fifty to one hundred and p seventy degrees and exposed to a mercury vapor lamp The preparations of further members of the class of while introducing chlorine gas. When no further hydrocompounds of the invention is given tabularly as follows:

Compound Starting Materials Method Reaction Conditions Boiling Point a,4-dlchloro-m-toluyl chloride -chloro-m-toluic acid A Reflux with 10 pts. S0012 12 hrs, Strip, -105 (1 111111.).

pass in C1; gas at 150 under irradiation by UV lamp until theoretical weight increase. a,P-dichloro-m-toluyl chloride m-Toluyl chloride A Add 1% F6012 pass in C1 at 30 until one 95105 (1 mm.).

molar equiv. HCl evolved, then distill oil the X-chloro-m-toluyl chloride and chlorinatc the distillate as above. Distill product. a,4,6-trich10tO-m-t0luyl ch1oride-. 4,6-dichlor0-m-toluic acid A As in first case above -115 (1111111.). 01,4,%6-tetrachloro-m-toluyl chlo- 4,5,6-trichl0ro-m-toluic acid A As above 130-140 (1 111111.).

I! G. a,a,4-trlchloro-m-toluyl chloride 4-chloro-m-xylcnc C Pass in chlorine at 150-170 until theoreti- 110-115 C. (1 mm.).

cal wt. increase for pentachlorination using ultraviolet radiation. Then add 5% conc. H2804 by weight, then one molar equiv. water dropwise at -150 C. Distill product. a,a,4,6-tetrachloro-m-toluyl chloride. 4,6-dichloro-m-xylene C As above -140 (1111111.). a,a1,l4l,5,t5pcnt80h10t0-m-t0luy1 4,5,6-tr1chloro-m-xylcne C As above -155 (1111111.).

C OH 0. aflxf l,5,6-hexachloro-m-toluyl .d0 0 As above 157-167 (1 mm.).

C 01 e. a,a,,4,fi-pentachloro-m-toluyl 4,6-dichloro-m-xy1enc M C As above, but chlorinated to theoretical 150-155 (1 mm.).

chloride. Weight increase for hexachlorination. a,5-dichloro-o-toluyl chloride 5-chloro-o-toluic acid... A Reflux with 5 pts.SOClz12hrs.,strip,pass 98108 (1 mm.).

in C12 at 150 under UV light until theoretical weight increase.

Compound Starting Materials Method Reaction Conditions Boiling Point a,a,5-trichloro-o-toluyl chloride..-.- 5-chloro-o-toluic acid A As above 110115 (1 mm.). a,a,a,o-tetrachloro-o-toluyl chloride. -..do A AS above 130140 (1 mm.). a,a,4,S-tGtIaChIOIO-O-toluYl chloride. 4,5-dichloroo-xylene Pass in C1; at 150-170 under UV light 130-140" (1111121.).

until theoretical weight increase for pentachlorination. Add cone. H2804, then one molar equiv. water dropwise at 120450". a,a,3,6-tetrachloro-o-toluyl chloride. 3,6-dichloro-o-xylene 0 As above 128-138" (1 mm.). a }?4,aafi-hexachloro-m-toluyl 4,5,6-trichloro-m-xylene 0 As above l50-160 (1 mm.).

C OI! e. a,a,3,4,5,G-hexachloro-o-toluyl Tetrachloro-o-xylene 0 Pass in chlorine at 150170 under UV 160-167 (1 mm.).

chloride. until theoretical wt. increase for penta- 0 I 8. a,2,5-trichloro-p-toluyl chloride. 01,3,4,5,6-pentachloro-o-toluyl chloride.

3-chloro-p-xylene 3-chloro-p-to1uic acid 2,5-(hichloro-p-xylene o 2,3,5-trichloro-p-xylene 2,5-dichloro-p-toluic acid. Tetrachloro-o-toluic acid.

chlorination. Add 5% cone. HzSO4, then one molar equiv. water dropwise at 120 150. As above As prep. A above. As prep. 0 above As prep. 0 above except chlorination carried to hexachlorination level. As prep. C above 110-115 (1 mm.). 105110 (1 mm.). 135-140 (1 mm.). 150-155 (1 mm.).

110-115" (1 mun). 145-155" (1 111111.).

As prep. A above Reflux with pts. SO01, 12 hrs., strip, pass in Oh at 150 under UV light until theoretical wt. increase.

Example 7.Preparation of emulsifiable concentrate formulation Pounds a,2,5-trichloro-p-toluyl chloride 2 Polyoxyethylene laurate emulsifier 0.5 Xylene to make total one gallon.

This produced a solution emulsifiable with water to prepare a sprayable emulsion.

Example 8.Preparati0n of oil solution formulation The following were blended:

Pounds a,a,3,6atetrachloro o-toluyl chloride 5 Diesel oil 95 This produced a clear solution sprayable as such.

Example 9.F0rmulation of granular formulation Granular clay, twenty-four to forty-eight mesh, was tumbled at one hundred degrees centigrade and sprayed with molten a,5-dichloro-o-toluyl chloride until a formulation containing ten percent by weight of the latter was obtained. This formulation was free-flowing and could be spread by hand or from a fertilizer spreader on the areas to be treated.

Example 10 An area of weedly farmland infested with ragweed, pigweed, lambsquarters, crabgrass, foxtail and mustard is sprayed with the chemicals of Examples 2, 3, 4 and 5 in a formulation as described in Example 8, at the rate of twenty pounds of the acid chloride per acre. Substantially one hundred percent destruction of the aboveground portions of the above weeds is obtained with n one week of spraying.

One month later, the area is plowed, disked, and planted to soybeans, which germinate and grow normally.

On the other hand, after spraying of test plots in the same field with'twenty pounds of 2,3,6-trichlorobenzoic acid or 3,6-dichloro-o-toluic acid .(giving equal weed destruction), severe stunting and malformation of soybeans is observed and even the following year, some malformation is observed when soybeans are planted in the treated area.

Example 11.Herbicidal use of a,a,2,3,5,6-pentachlorop-toluyl chloride A field area infested with seeds of wild oats and broadleaf annual weeds, principally ragweed, lambsquarters, and pigweed was plowed, disked, and seeded with corn. Prior to corn and weed germination, the area was sprayed at the rate of eight pounds (of active ingredient), per acre with an emulsi'fiable formulation of a,a,2,3,5,6-pentachloro-p-toluyl chloride dispersed in water. One month later, the area was found to bear a healthy stand of corn, essentially weed free. Comparison plots either left unsprayed or sprayed at the rate of eight pounds per acre with 2,3,5,6-tetrachloro-p-toluyl chloride were infested with broadleaf weeds and wild oats.

Example 12 destruction of goldenrod and dandelion and negligible.

damage to the other weed species.

We claim:

A herbicidal composition comprising a minor proportion of a herbicidal compound of the chemical formula where m is from one to four and n is from one to two, a minor proportion of another herbicidal material, a minor proportion of a surface active agent and a major proportion of a liquid diluent material which facilitates application of the herbicides to loci where herbaceous growth is to be inhibited.

References Cited by the Examiner UNITED STATES PATENTS 2,854,325 9/ 1958 Searle 260-344 X FOREIGN PATENTS 820,696 8/1937 France.

OTHER REFERENCES Beilstein: Organische Chemie, vol. 17, pp. 483 and LORRAINE A. WEINBERGER, Primary Examiner.

LEON ZITVER, Examiner.

F. D. HIGEL, R. K. JACKSON, Assistant Examiners.