Process for preparing substituted diphenyl ethers

A process for preparing a diphenyl ether of the graphic formula:

• ##STR10## wherein:
• X is hydrogen or halogen;
• Y is hydrogen, halogen, cyano, trifluoromethyl, or an alkyl radical containing from 1 to 4 carbon atoms;
• Z is oxygen or sulfur;
• R is methylidene or monosubstituted methylidene, wherein the substituent is selected from the group consisting of alkyl, oxoalkyl and hydroxyalkyl radicals containing from 1 to 4 carbon atoms;
• and
• R.sup.1 is hydrogen, or an alkyl radical containing from 1 to 8 carbon atoms, a cycloalkyl radical containing from 3 to 8 carbon atoms, an agronomically acceptable cationic salt, phenyl, or mono-, di-, or trisubstituted phenyl, said substituents being selected from the group consisting of halogen, alkyl or alkoxy radicals containing from 1 to 10 carbon atoms, cyano, nitro, and trifluoromethyl;
• which comprises the sequential steps of:
• (a) reacting a diphenyl ether of the graphic formula:
• ##STR11## wherein X and Y are as defined above, with potassium hydroxide in the presence of methanol at temperatures from about 50.degree. C. to 200.degree. C. to form the corresponding acid salt;
• (b) reacting the acid salt of step (a) with ethyl-2-chloropropionate in the presence of dimethylsulfoxide at temperatures from about 50.degree. C. to 200.degree. C. to form the corresponding ester;
• and
• (c) nitrating the ester product of step (b) with a mixture of nitric acid, sulfuric acid and acetic anhydride as nitrating agent.

A process for the continuous preparation of diphenyl ether of the formula:

• ##STR12## wherein:
• X is hydrogen or halogen;
• Y is hydrogen, halogen, cyano, trifluoromethyl, or an alkyl radical containing from 1 to 4 carbon atoms;
• X is oxygen or sulfur;
• R is a methylidene or monosubstituted methylidene, wherein the substituent is selected from the group consisting of alkyl, oxoalkyl and hydroxyalkyl radicals containing from 1 to 4 carbon atoms;
• and
• R.sup.1 is hydrogen, or an alkyl radical containing from 1 to 8 carbon atoms, a cycloalkyl radical containing from 3 to 8 carbon atoms, an agronomically acceptable cationic salt, phenyl, or mono-, di-, or trisubstituted phenyl, said substituents being selected from the group consisting of halogen, alkyl or alkoxy radicals containing from 1 to 10 carbon atoms, cyano, nitro, and trifluoromethyl;
• which comprises the sequential steps of:
• (a) reacting a diphenyl ester of Formula II with an inorganic alkali metal base to form an acid salt;
• (b) esterifying the acid salt of step (a) with an halocarboxylic acid ester of Formula III;
• and
• (c) nitrating the ester product of step (b), withdrawing a portion of reaction medium containing diphenyl ether product and introducing additional reactants to maintain the desired quantity in the reaction medium.