Organic solvent-free process for the preparation of 2-(2-nitrophenylazo)phenols

A process for the preparation of a 2-(2-nitrophenylazo) substituted phenol of the formula I

• which process comprises combining an ortho-nitroaniline of formula II
• a phenol of formula (III)
• a nitrosating agent and
• optionally a surface active agent,
• together to provide a reaction mixture and
• reacting the mixture for a sufficient time without isolation of intermediate products,
• wherein no organic solvent is added to the reaction mixture;
• and wherein
• G1 is hydrogen,
• G2 is perfluoroalkyl (CnF2n+1) where n is equal to 1–12,
• R1 is phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or said phenylalkyl substituted on the phenyl ring by one to three alkyl of 1 to 4 carbon atoms,
• R2 is straight or branched alkyl chain of 1 to 24 carbon atoms, straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or said phenylalkyl substituted on the phenyl ring by one to three alkyl of 1 to 4 carbon atoms;
• or R2 is said alkyl of 1 to 24 carbon atoms or said alkenyl of 2 to 18 carbon atoms substituted by one or more —OH, —OCOE11, —OE4, —NCO, —NHCOE11 or —NE7E8, or mixtures thereof, where E4 is straight or branched chain alkyl of 1 to 24 carbon atoms;
• alkenyl of 2 to 18 carbon atoms;
• or said alkyl or said alkenyl interrupted by one or more —O—, —NH— or —N(C1–C24)alkyl- groups or mixtures thereof and which can be unsubstituted or substituted by one or more —OH, or —NH2 groups or mixtures thereof;
• or R2 is —(CH2)m—CO-E5;
• E5 is OE6 or NE7E8, or E5 is —PO(OE12)2, —OSi(E11)3 or —OCO-E11, or straight or branched chain C1–C24alkyl which can be interrupted by —O—, —S— or —NE11 and which can be unsubstituted or substituted by —OH or —OCO-E11, C5–C12 cycloalkyl which is unsubstituted or substituted by —OH, straight chain or branched C2–C18alkenyl which is unsubstituted or substituted by —OH, C7–C15aralkyl, —CH2—CHOH-E13 or glycidyl,
• E6 is hydrogen, straight or branched chain C1–C24alkyl which is unsubstituted or substituted by one or more OH, OE4 or NH2 groups, or —OE6 is —(OCH2CH2)wOH or —(OCH2CH2)wOE21where w is 1 to 12 and E21 is alkyl of 1 to 12 carbon atoms,
• E7and E8 are independently hydrogen, alkyl of 1 to 18 carbon atoms, straight or branched chain alkenyl of 2 to 18 carbon atoms, straight or branched chain C3–C18alkyl which is interrupted by —O—, —S— or —NE11-, C5–C12cycloalkyl, C6–C14aryl or C1–C3hydroxylalkyl, or E7 and E8 together with the N atom are a pyrrolidine, piperidine, piperazine or morpholine ring, or
• E5 is —X-(Z)p—Y-E15
• wherein
• X is —O— or —N(E16)-,
• Y is —O— or —N(E17)-,
• Z is C2–C12-alkylene, C4–C12-alkylene interrupted by one to three nitrogen atoms, oxygen atoms or a mixture thereof, or is C3–C12-alkylene, butenylene, butynylene, cyclohexylene or phenylene, each substituted by a hydroxyl group,
• m is zero, 1 or 2,
• p is 1, or p is also zero when X and Y are —N(E16)- and —N(E17)-, respectively,
• E15 is a group —CO—C(E18)═C(H)E19 or, when Y is —N(E17)-, forms together with E17 a group
• —CO—CH═CH—CO—, wherein E18 is hydrogen or methyl, and E19 is hydrogen, methyl or
• —CO—X-E20, wherein E20 is hydrogen, C1–C12-alkyl, and E16 and E17 independently of one another are hydrogen, C1–C12-alkyl, C3–C12-alkyl interrupted by 1 to 3 oxygen atoms, or is cyclohexyl or
• C7–C15aralkyl, and E16 together with E17 in the case where Z is ethylene, also forms ethylene,
• E11 is hydrogen, straight or branched chain C1–C18alkyl, C5–C12cycloalkyl, straight or branched chain C2–C18alkenyl, C6–C14aryl or C7–C15aralkyl,
• E12 is straight or branched chain C1–C18alkyl, straight or branched chain C3–C18alkenyl, C5–C10cycloalkyl, C6–C16aryl or C7–C15aralkyl, and
• E13 is H, straight chain or branched C1–C18alkyl which is substituted by —PO(OE12)2, phenyl which is unsubstituted or substituted by OH, C7–C15aralkyl or —CH2OE12.