Process and composition for inhibiting the polymerization of cyclopentadiene compounds

A process for inhibiting the polymerization of a cyclopentadiene compound (B), comprising:

• contacting the cyclopentadiene compound (B) with at least one compound (A);
• wherein
• (A) is a compound of structure (I)
• wherein
• R1 and R2 are each independently hydrogen, alkyl of 1 to 18 carbon atoms, cycloalkyl of 3 to 15 carbon atoms, aryl of 6 to 15 carbon atoms or phenylalkyl of 7 to 15 carbon atoms;
• R3 is —CN, —COOH, —COOR4, —COR5, —OCOR6, —CONR7R8, —PO(OR9)2, —O—R10, —S—R11, —R12, —C≡C—R13 or halogen;
• wherein
• R4, R5, R6 are alkyl of 1 to 18 carbon atoms, cycloalkyl of 3 to 12 carbon atoms, aryl of 6 to 10 carbon atoms;
• R7 and R8 are each independently hydrogen;
• alkyl of 1 to 15 carbon atoms which is optionally substituted with at least one substituent selected from the group consisting of alkylamino having 1 to 4 carbon atoms, dialkylamino having 2 to 8 carbon atoms and hydroxyl;
• phenylalkyl of 7 to 15 carbon atoms which is optionally substituted with at least one substituent selected from the group consisting of hydroxyl, alkyl having 1 to 4 carbon atoms, alkylamino having 1 to 4 carbon atoms and dialkylamino having 2 to 8 carbon atoms;
• aryl of 6 to 10 carbon atoms which is optionally substituted with at least one substituent selected from the group consisting of alkyl having 1 to 4 carbon atoms, alkylamino having 1 to 4 carbon atoms, dialkylamino having 2 to 8 carbon atoms and hydroxyl;
• or NR7R8 is morpholino, piperidino or pyrrolidino;
• R9, R10, R11 are hydrogen;
• alkyl of 1 to 15 carbon atoms which is optionally substituted with at least one substituent selected from the group consisting of hydroxyl, dialkylamino, —OR14, —[O(CH2)y]xH, where x is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 and y is 1, 2, 3 or 4 and where R14 is alkyl of 1 to 6 carbon atoms;
• cycloalkyl of 3 to 15 carbon atoms which is optionally substituted with at least one substituent selected from the group consisting of hydroxyl, dialkylamino, —OR14, —[O(CH2)y]xH, where x is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 and y is 1, 2, 3 or 4 and where R14 is alkyl of 1 to 6 carbon atoms;
• phenylalkyl of 7 to 15 carbon atoms which is optionally substituted with at least one substituent selected from the group consisting of hydroxyl, dialkylamino, —OR14, —[O(CH2)y]xH, where x is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 and y is 1, 2, 3 or 4 and where R14 is alkyl of 1 to 6 carbon atoms;
• or aryl of 6 to 15 carbon atoms which is optionally substituted with at least one substituent selected from the group consisting of hydroxyl, dialkylamino, —OR14, —[O(CH2)y]xH, where x=1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 and y=1, 2, 3 or 4 and where R14=alkyl of 1 to 6 carbon atoms;
• R12 is 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-thienyl, 3-thienyl, 2-pyrryl, 3-pyrryl, 2-furyl, 3-furyl or aryl of 6 to 15 carbon atoms;
• wherein the radicals 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-thienyl, 3-thienyl, 2-pyrryl, 3-pyrryl, 2-furyl, 3-furyl or aryl of 6 to 15 carbon atoms are optionally substituted with at least one substituent selected from the group consisting of hydroxyl, nitro, amino, cyano, carboxyl, aminocarbonyl, halogen, alkyl of 1 to 8 carbon atoms, alkoxy of 1 to 8 carbon atoms, alkylthio of 1 to 8 carbon atoms, alkylamino of 1 to 8 carbon atoms, dialkylamino of 2 to 8 carbon atoms and a carboxylic ester group of 2 to 8 carbon atoms;
• R13 is hydrogen, alkyl of 1 to 12 carbon atoms, aryl of 6 to 10 carbon atoms, wherein the aryl of 6 to 10 carbon atoms is optionally substituted with at least one substituent selected from the group consisting of hydroxyl, nitro, amino, cyano, carboxyl, aminocarbonyl, halogen, alkyl of 1 to 8 carbon atoms, alkoxy of 1 to 8 carbon atoms, alkylthio of 1 to 8 carbon atoms, alkylamino of 1 to 8 carbon atoms, dialkylamino of 2 to 8 carbon atoms and a carboxylic ester group of 2 to 8 carbon atoms;
• and
• wherein the substituents R1, R2 and R3 are the same or different.