A copper catalyst obtained by reducing a precursor containing copper and aluminum and not containing substantially malachite and aluminum hydroxide permits preparation of amides with a high productivity and in a high selectivity by the hydration of nitrites.
The components present in the sample with a mobile phase A in 1st section is separated. In 2nd section there is provided with an inserting line of a dilute solution for diluting the mobile phase A and a trapping column which forces the dilute solution to pass but catches the components b
