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|Section2= |Section3= }} Adams's catalyst, also known as platinum dioxide, is usually represented as platinum(IV) oxide hydrate, PtO2•H2O. It is a catalyst for hydrogenation and hydrogenolysis in organic synthesis. This dark brown powder is commercially available. The oxide itself is not an active catalyst, but it becomes active after exposure to hydrogen whereupon it converts to platinum black, which is responsible for reactions. ==Preparation== Adams's catalyst is prepared from chloroplatinic acid H2PtCl6 or ammonium chloroplatinate, (NH4)2PtCl6, by fusion with sodium nitrate. The first published preparation was reported by V. Voorhees and Roger Adams. The procedure involves first preparing a platinum nitrate which is then heated to expel nitrogen oxides. ::H2PtCl6 + 6 NaNO3 → Pt(NO3)4 + 6 NaCl (aq) + 2 HNO3 ::Pt(NO3)4 → PtO2 + 4 NO2 + O2 The resulting brown cake is washed with water to free it from nitrates. The catalyst can either be used as is or dried and stored in a desiccator for later use. Platinum can be recovered from spent catalyst by conversion to ammonium chloroplatinate using aqua regia followed by ammonia. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Adams's catalyst」の詳細全文を読む スポンサード リンク
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