新试剂5-(3-甲基-2-吡啶)-亚甲基若丹宁与钯显色反应研究

STUDY ON THE COLOR REACTION OF PALLADIUM(Ⅱ) WITH 5-(3-METHYL-2-PYRIDYL)-METHYLENERHODANINE

合成了新试剂 5- ( 3-甲基 - 2 -吡啶 ) -亚甲基若丹宁 ( MPMR) ,研究了其与钯的显色反应在 p H值为 4 .0～ 6.5介质中 ,吐温 - 80和 Triton X- 1 0 0混合表面活性剂存在下 ,MPMR和 Pd2 +生成 2∶ 1配合物 ,λmax=4 35nm,ε=6.1 5× 1 0 4 L·mol- 1 ·cm- 1 。钯含量在 0～ 30 μg/2 5ml内符合比耳定律 ,方法用于钯催化剂中钯的测定 ,结果满意。

A new chromogenic reagent 5 (3 methyl 2 pyridyl) methylenerhodanine (MPMR) was synthesised and identified. The color reaction of palladium(Ⅱ) with MPMR was studied. In the presence of Triton X 100 and Tween 80, MPMR can react with Pd 2+ to form a 2∶1 stable complex in pH 4.8 HOAc NaOAc buffer medium. The maximum absorption lies at 435nm with a malor absorptivity of 6.15×10 4L·mol -1 ·cm -1 . Beer′s law is obeyed in the range of 0~30μg/25ml. This method has been applied to the determination of palladium in catalyst with satisfactory results.