Abstract: A method for preparing 3,3?-diaminobenzidine, the method comprising the following steps: subjecting 4,4?-biphenol and N,N-dimethylsulfamoyl chloride to an esterification reaction in a specified solvent at 40-70° C. to obtain 4,4?-biphenyl bis(N,N-dimethylaminosulfonate) as a first intermediate; subjecting the 4,4?-biphenyl bis(N,N-dimethylaminosulfonate) to a chlorination reaction with a chlorinating reagent under acidic conditions to obtain 3,3?-dichloro-4,4?-biphenyl bis(N,N-dimethylaminosulfonate) as a second intermediate; subjecting the second intermediate 3,3?-dichloro-4,4?-biphenyl bis(N,N-dimethylaminosulfonate) to an ammonolysis reaction with anammoniation reagent in the presence of a combined catalyst to obtain a crude product of 3,3?,4,4?-tetraaminobiphenyl, wherein the combined catalyst is a mixture of proline, a cuprous salt and a phase transfer catalyst; and subjecting the crude product of 3,3?,4,4?-tetraaminobiphenyl to a post-treatment to obtain a purified 3,3?,4,4?-tetraaminobiphenyl product.

Abstract: A method for preparing-3,3?-diaminobenzidine, the method comprising the following steps: subjecting 4,4?-biphenol and N,N-dimethylsulfamoyl chloride to an esterification reaction in a specified solvent at 40-70° C. to obtain 4,4?-biphenyl bis(N,N-dimethylaminosulfonate) as a first intermediate; subjecting the 4,4?-biphenyl bis(N,N-dimethylaminosulfonate) to a chlorination reaction with a chlorinating reagent under acidic conditions to obtain 3,3?-dichloro-4,4?-biphenyl bis(N,N-dimethylaminosulfonate) as a second intermediate; subjecting the second intermediate 3,3?-dichloro-4,4?-biphenyl bis(N,N-dimethylaminosulfonate) to an ammonolysis reaction with anammoniation reagent in the presence of a combined catalyst to obtain a crude product of 3,3?,4,4?-tetraaminobiphenyl, wherein the combined catalyst is a mixture of proline, a cuprous salt and a phase transfer catalyst; and subjecting the crude product of 3,3?,4,4?-tetraaminobiphenyl to a post-treatment to obtain a purified 3,3?,4,4?-tetraaminobiphenyl product.

Abstract: A surgical tool for piercing tissue of a body comprises a hollow external component (1) having a peripheral wall (11), an internal component (2) movable disposed inside the external component (1) and having a piercing head (21); when the piercing head (21) and the internal component (2) retract relative to the external component (1), the movable component (3) deforms partially, expands outwardly in a radial direction, and fills the bladder (6). The movable component can be deformed to expand outward in the radial direction, so as to make the bladder to expand, so that the surgical tool can be positioned on the body of the patient.