Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C59/00—Compounds having carboxyl groups bound to acyclic carbon atoms and containing any of the groups OH, O—metal, —CHO, keto, ether, groups, groups, or groups
  • C07C59/40—Unsaturated compounds
  • C07C59/58—Unsaturated compounds containing ether groups, groups, groups, or groups
  • C07C59/64—Unsaturated compounds containing ether groups, groups, groups, or groups containing six-membered aromatic rings
  • C07C59/66—Unsaturated compounds containing ether groups, groups, groups, or groups containing six-membered aromatic rings the non-carboxylic part of the ether containing six-membered aromatic rings
  • C07C59/68—Unsaturated compounds containing ether groups, groups, groups, or groups containing six-membered aromatic rings the non-carboxylic part of the ether containing six-membered aromatic rings the oxygen atom of the ether group being bound to a non-condensed six-membered aromatic ring
  • C07C59/70—Ethers of hydroxy-acetic acid, e.g. substitutes on the ring
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
  • C07C37/62—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by introduction of halogen; by substitution of halogen atoms by other halogen atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/347—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups
  • C07C51/363—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups by introduction of halogen; by substitution of halogen atoms by other halogen atoms

Definitions

• chlorinate phenols by means ofchlorine or other chlorinating agents for example sulphuryl chloride, and to carry out the reaction in the presence of added I catalysts in order to increase the yield of chlorinated products, or, in those instances in which more than one chlorinated product can be for-med, to increase the yield of a desired product at the expense of other possible products.
• chlorinated products by means ofchlorine or other chlorinating agents for example sulphuryl chloride
• the two principal products formed are 4-chloro-2-methylphenol and 6- chloro-Z-methylphenol.
• the 4-chloro isomer is the more valuable as an intermediate for the manufacture of herbicidal com-pounds, so that methods of reducing the proportion of the undesired 6- chloro isomer are of commercial value.
• the proportion of 4-chloro-2-methylphenol in the prodnot formed by chlorinating ortho-cresol can be increased by chlorinating the ortho-cresol with sulphuryl chloride in the presence of a metal chloride.
• highly coloured impurities in the chlorocresol are retained in the final product. Consequently, the full value of this improvement in the yield of the 4-ch1oro isomer cannot be realised in practice because the product still requires distillation before it can be used further for the manufacture of saitsfactorily light-coloured products, particularly 2-methyl- 4-chlorophenoxy acetic acid and its derivatives.
• the fullers earth may be a commercial natural or activated grade, and is preferably dried before use to minimise the adverse effect of water on the metal halide cata-' yst.
• the metal halide catalysts which may be used are in general, volatile metal halides, and particularly the halides of aluminum, iron, tin, titanium and zinc.
• the preferred metal halide catalyst is aluminum chloride, as it is a cheap material which is a very active catalyst and enables a chlorocresol of light colour and good quality to be obtained by our process with the least difficulty of operation.
• ther catalysts which may be used include ferric chloride, .annic chloride, titanium tetrachloride and zinc chloride.
• he proportion of metal halide catalyst to be used is prefrably between about 0.5% and 2% of the weight of the rtho-cresol, as greater proportions tend to produce little dditional effect. Smaller proportions are usually suitble only when the reactants are thoroughly dried. lnert Jlvents or diluents may be added if desired.
• the metal halide should be substantially anhydrous if s beneficial effect on the formation of the para chloro tomer is to be obtained.
• the adverse effect of ater on the isomer ratio of the product is preferably iinimised by using substantially anhydrous materials, specially the ortho-cresol, and by excluding moisture tom the reaction vessel.
• the chlorinated cresol is very suitable for direct onversion into 2-methyl-4-chlorophenoxy aliphatic acids for example 2-methyl-4-chlorophenoxyacetic acid, by :ondensation with caustic soda and monochloroacetic .cid) and compositions derived therefrom, and yields a elatively light-coloured product.
• it is [011 essential to remove the fullers earth before conversion 2-methyl-4-chlorophenoxyacetic acid, and removal after :ondensation is satisfactory.
• the invention is illustrated but not limited by the folowing example in which the parts and percentages are ⁇ y weight.
• Example 1 297 parts of sulphuryl chloride are added over a period )f 30 minutes to a mixture of 216 parts of ortho-cresol, I.4% (i.e. 0.86 part) of anhydrous aluminum chloride 1nd 0.5% (i.e. 1.08 parts) of activated fullers earth (a :alcium montmorillonite) which is initially at a temperaure of 30 C. and is cooled gradually to C. during he addition.
• activated fullers earth a :alcium montmorillonite
• a mixture of 142.5 parts of the above-described chlorinated ortho-cres-ol and 72.7 parts of monochloroacetic acid is heated to 100 C. and stirred while a slow stream of nitrogen is passed through it. 283.2 parts of an aqueous solution of caustic soda are then added rapidly with continued stirring to the above mixture, the rate of addition being such that the temperature of the reaction mixtures does not exceed about 109 C. and stabilises itself when the addition is complete at about 100-103 C.
• the mixture is maintained at 100-103" C. for 1 hour more and then 40 parts of an aqueous 25 solution of caustic soda and 21.7 parts of molten monochloroacetic acid are added, separately and simultaneously, and the whole is stirred for a further hour at l00103 C.
• the mixture is filtered to remove the small quantity of fullers earth present, is then acidified to approximately pH 6 by the addition of a small quantity of concentrated hydrochloric acid, and steam distilled to remove uncondensed materials (mainly chlorocresols). This distillation is continued until about 200 parts of distillate have been produced.
• the hot mixture is then acidified to approximately pH 2 by the addition of more hydrochloric acid (about 116 parts of hydrochloric acid of specific gravity 1.16 are required), and the molten layer of crude 4-chloro-2-methylphenoxy-acetic acid which is thereby formed is separated off from the aqueous layer.
• the aqueous layer is cooled to atmospheric temperature, and the further quantity of organic acid thus precipitated is collected, combined with the molten organic layer previously separated, and the whole is then partially dried by heating at 100110 C. for minutes.
• the resulting product consists of 189.4 parts of material which is found by analysis to contain 82.8- '-3% of 4- chloro-2-methylphenoxyacetic acid, 89.3:3% of total chloro-2-methylphenoxyacetic acids.
• the yield corresponds to a yield of total acids of 84.4% of theory, of which 92.7% is the 4-chloro isomer, assuming the mean value of the analyses.
• the mixed acids are then neutralised with aqueous potassium hydroxide solution, 1.5% of potassium citrate is added as sequestering agent, and the solution is adjusted to pH 11.0 and to contain 32.2% of total acids (3l.0i0.5% of 4-chloro-2-methylphenoxyacetic acid).
• This solution is slightly darker in colour than a solution prepared in a similar manner from distilled 4-chloro-orthocresol.
• Example 2 The procedure of Example 1 is repeated except that the anhydrous aluminum chloride is replaced by an equal weight of anhydrous zinc chloride. The procedure is also repeated using the zinc chloride but omitting the fullers earth.
• a process for the chlorination of ortho-cresol which comprises reacting ortho-cresol and sulphuryl chloride at a temperature within the range of approximately 2075 C. in the presence of from 0.5% to 2% by weight of a metal halide catalyst selected from the group consisting of the halides of aluminum, iron, tin, titanium and zinc, and from 0.5% to 1.5% by weight of fullers earth to produce chlorinated ortho-cresol, the amounts of catalyst and fullers earth being based on the weight of ortho-cresol.
• reaction mixture is maintained at approximately 30 C. at the start of the chlorination and is cooled progressively during the reaction to about 20 C.
• a process for the chlorination of ortho-cresol which comprises reacting ortho-cresol and sulphuryl chloride at a temperature Within the range of approximately 20-30" C. in the presence of from 0.5% to 2% by weight of a metal halide catalyst selected from the group consisting of the chlorides of aluminum, iron, tin, titanium and zinc, and from 0.5% to 1.0% by weight, of fullers earth, to produce chlorinated ortho-cresol, the amounts of catalyst 6 and fullers earth being based on the weight of orthocresol.
• a metal halide catalyst selected from the group consisting of the chlorides of aluminum, iron, tin, titanium and zinc, and from 0.5% to 1.0% by weight, of fullers earth

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• Oil, Petroleum & Natural Gas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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  • NL NL274287D patent/NL274287A/xx unknown
• 1961
  • 1961-02-03 GB GB4125/61A patent/GB926014A/en not_active Expired
• 1962
  • 1962-01-18 DE DEJ21176A patent/DE1175690B/de active Pending
  • 1962-01-29 US US169663A patent/US3318949A/en not_active Expired - Lifetime
  • 1962-01-31 SE SE1096/62A patent/SE301155B/xx unknown

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