定义Definition
奥斯特瓦尔德法是工业制硝酸的方法：氨在铂铑催化网上被空气氧化为一氧化氮，NO 进一步被氧化为二氧化氮，NO₂ 被水吸收生成硝酸。
The Ostwald process is the industrial route to nitric acid: ammonia is oxidised by air over a platinum–rhodium gauze to nitric oxide, NO is further oxidised to nitrogen dioxide, and NO₂ is absorbed in water to form nitric acid.
工艺步骤Process steps
①4NH₃ + 5O₂ → 4NO + 6H₂O（Pt–Rh，约 850–900 °C，接触时间约 1 ms，强放热）；②冷却后 2NO + O₂ → 2NO₂；③3NO₂ + H₂O → 2HNO₃ + NO，生成的 NO 返回氧化。产品为约 60–68% 的硝酸。
(1) 4NH₃ + 5O₂ → 4NO + 6H₂O over Pt–Rh at about 850–900 °C with ~1 ms contact time, strongly exothermic; (2) after cooling, 2NO + O₂ → 2NO₂; (3) 3NO₂ + H₂O → 2HNO₃ + NO, the NO being recycled. The product is about 60–68 % nitric acid.
由来Origin
德国化学家威廉·奥斯特瓦尔德于 1902 年申请专利，1908 年首家工厂投产。与哈伯-博施合成氨结合后，彻底摆脱了对智利硝石的依赖，对化肥和炸药工业影响深远。奥斯特瓦尔德因催化等研究获 1909 年诺贝尔化学奖。
The German chemist Wilhelm Ostwald patented it in 1902 and the first plant ran in 1908. Combined with Haber–Bosch ammonia it ended dependence on Chilean saltpetre, transforming the fertiliser and explosives industries. Ostwald won the 1909 Nobel Prize in Chemistry for work including catalysis.
选择性与环保Selectivity and environment
催化网温度和接触时间决定选择性，过低温度生成 N₂ 和副产物 N₂O（强温室气体）。现代工厂设置 N₂O 分解催化剂和尾气 NOₓ 处理。铂会缓慢流失，需用钯网回收。
Gauze temperature and contact time control selectivity; too low a temperature gives N₂ and by-product N₂O, a potent greenhouse gas. Modern plants add N₂O decomposition catalysts and tail-gas NOₓ abatement; platinum lost slowly is recovered with palladium gauzes.
反应Reactions
Pt–Rh 网，850–900 °C，常压至约 10 atm；随后冷却吸收
Pt–Rh gauze, 850–900 °C, 1–10 atm; then cooling and absorption
氨催化氧化为 NO。
Catalytic oxidation of ammonia to NO.
NO 被氧气氧化为 NO₂。
NO oxidised by oxygen to NO₂.
NO₂ 在吸收塔中与水反应生成 HNO₃。
NO₂ reacts with water in absorption towers to form HNO₃.
第一步强放热。
The first step is strongly exothermic.
年表Timeline
- 1902
奥斯特瓦尔德申请专利
Ostwald files his patent
- 1908
首个工厂投产
First plant starts operating
- 1909
奥斯特瓦尔德获诺贝尔化学奖
Ostwald receives the Nobel Prize in Chemistry