1. A grease composition containing a lubricant base oil, diurea compounds represented by the following general formulas (1) to (3), and at least one species selected from the group consisting of paraffin oxides and phosphorus compounds; wherein respective contents of the diurea compounds represented by the following general formulas (1) to (3) satisfy conditions defined by the following expressions (4) and (5); and wherein the total content of the paraffin oxides and phosphorus compounds is 0.1 to 15 mass % based on the total amount of the grease composition:
where R1 is a hydrocarbon group containing an aromatic ring, R2 is a divalent hydrocarbon group, and R3 is a hydrocarbon group containing an aliphatic ring;
5\u2266W1+W2+W3\u226630 \u2003\u2003(4)
0.3\u2266(W1+0.5\xd7W2)(W1+W2+W3)\u22660.7 \u2003\u2003(5)
where W1, W2, and W3 are respective contents (mass %) of the diurea compounds represented by general formulas (1) to (3) based on the total amount of the grease composition.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method for producing biphenyl and its derivative comprising oxidatively coupling an aromatic compound represented by formula (1):
7
wherein R represents a substitutent; and m represents an integer of 0 to 4, in the presence of a palladium salt, a copper salt, and a bidentate ligand compound capable of forming a complex with the palladium salt via the nitrogen atom and the oxygen atom in the molecule thereof in an atmosphere containing molecular oxygen.
2. The method for producing biphenyl and its derivative according to claim 1, wherein the aromatic compound represented by formula (1) in which m is an integer of 1 to 3 is used to selectively produce an asymmetrically substituted biphenyl derivative.
3. The method for producing biphenyl and its derivative according to claim 2, wherein a phthalic diester is used as the aromatic compound represented by formula (1) to selectively produce a 2,3,3,4-biphenyltetracarboxylic acid tetraester.
4. The method for producing biphenyl and its derivative according to claim 1, wherein the oxidative coupling is carried out at a temperature of 50 to 300 C.
5. The method for producing biphenyl and its derivative according to claim 1, wherein the bidentate ligand compound is a nitrogen-containing heterocyclic compound having an oxygen-containing substituent and represented by formula (2):
8
wherein R1 represents an alkyl group, an aryl group, an alkoxy group, an amino group or a hydroxyl group; L represents CH or N; and n represents an integer of 0 to 3.
6. The method for producing biphenyl and its derivative according to claim 1, wherein the bidentate ligand compound is a nitrogen-containing heterocyclic compound having an oxygen-containing substituent and represented by formula (3):
9
wherein R2 represents a hydroxyl group or COR1; and R1 represents an alkyl group, an aryl group, an alkoxy group, an amino group or a hydroxyl group.
7. The method for producing biphenyl and its derivative according to claim 1, wherein the bidentate ligand compound is an amino compound represented by formula (4):
10
wherein R1 represents an alkyl group, an aryl group, an alkoxy group, an amino group or a hydroxyl group; R3 and R4 each represent a hydrogen atom, an alkyl group or an aryl group; and n represents an integer of 0 to 3.