Method for producing modified conjugated diene-based polymer, modified conjugated diene-based polymer, polymer composition, cross-linked product, and tire

A modified conjugated diene-based polymer represented by formula (3):

• wherein:
• X2 represents a group represented by formula (4-1) or (4-2);
• A1 represents a C1 to C20 (i+k)-valent hydrocarbon group or a C1 to C20 (i+k)-valent group which has at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom, and no active hydrogen and which bonds to each of group “—Si(R1)n(Y1)3−n” and the group represented by formula (4-2) via a carbon atom;
• R1 represents a C1 to C20 hydrocarbyl group;
• Y1 represents group “—OR2” or group “—NR3R4”;
• each of R2, R3, and R4 independently represents a C1 to C20 hydrocarbyl group;
• n is an integer of 0 to 2;
• when n is 0 or 1, a plurality of groups “Y1” are identical to or different from one another;
• when n is 2, a plurality of groups “R1” are identical to or different from one another;
• each of i and k is independently an integer of 1 to 6, satisfying i+k≤10;
• when a plurality of groups “X2” are present in formula (3), the plurality of groups “X2” are identical to or different from one another;
• and
• when a plurality of groups “—Si(R1)n(Y1)3−n” are present, the plurality of groups “—Si(R1)n(Y1)3−n” are identical to or different from one another;
• wherein, in formula (4-1):
• Z1 represents a single bond, a C1 to C8 alkanediyl group, or group “*3—Ar1—W1—”;
• Ar1 represents a divalent aromatic ring group;
• W1 represents a single bond or a methylene group;
• “*3” represents a bond to Q1;
• each of R6 and R7 independently represents a C1 to C10 hydrocarbylene group;
• each of Q1 and Q2 independently represents a nitrogen atom or —CR10—;
• when Z1 is a single bond, Q1 is a nitrogen atom;
• R10 represents a hydrogen atom or a C1 to C20 hydrocarbyl group;
• Poly represents a modified or unmodified conjugated diene-based polymer chain;
• and
• “*” represents a bond, and;
• wherein, in formula (4-2):
• Z2 represents a single bond, a C1 to C8 alkanediyl group, or group “*4—Ar1—W1—”;
• Ar1 represents a divalent aromatic ring group;
• W1 represents a single bond or a methylene group;
• “*4” represents a bond to —NR11—;
• R11 represents a hydrogen atom, a C1 to C20 hydrocarbyl group, or a trihydrocarbylsilyl group;
• Poly represents a modified or unmodified conjugated diene-based polymer chain;
• and
• “*” represents a bond.

A compound represented by formula (1):

• wherein:
• X1 represents a group represented by formula (2-1) or (2-2);
• A1 represents a C1 to C20 (i+k)-valent hydrocarbon group or a C1 to C20 (i+k)-valent group which has at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom, and no active hydrogen and which bonds to each of group “—Si(R1)n(Y1)3−n” and the group represented by formula (2-2) via a carbon atom;
• R1 represents a C1 to C20 hydrocarbyl group;
• Y1 represents group “—OR2” or group “—NR3R4”;
• each of R2, R3, and R4 independently represents a C1 to C20 hydrocarbyl group;
• n is an integer of 0 to 2;
• when n is 0 or 1, a plurality of groups “Y1” are identical to or different from one another;
• when n is 2, a plurality of groups “R1” are identical to or different from one another;
• each of i and k is independently an integer of 1 to 6, satisfying i+k≤10;
• when a plurality of groups “X1” are present in formula (1), the plurality of groups “X1” are identical to or different from one another;
• and
• when a plurality of groups “—Si(R1)n (Y1)3−n” are present, the plurality of groups “—Si(R1)n(Y1)3−n” are identical to or different from one another;
• wherein, in formula (2-1):
• R5 represents a hydrogen atom, a C1 to C8 haloalkyl group, or a monovalent cyclic group having a structure in which a halogen atom or a methyl group is bound to an aromatic ring;
• each of R6 and R7 independently represents a C1 to C10 hydrocarbylene group;
• each of Q1 and Q2 independently represents a nitrogen atom or —CR10—;
• when R5 is a hydrogen atom, Q1 is a nitrogen atom;
• R10 represents a hydrogen atom or a C1 to C20 hydrocarbyl group;
• and
• “*” represents a bond;
• wherein in formula (2-2):
• R8 represents a hydrogen atom, a C1 to C8 haloalkyl group, or a monovalent cyclic group having a structure in which a halogen atom or a methyl group is bound to an aromatic ring;
• R9 represents a C1 to C20 hydrocarbyl group or a trihydrocarbylsilyl group;
• when R9 is a hydrogen atom, R9 is a C1 to C20 hydrocarbyl group;
• and
• “*” represents a bond.