一氧化二氮，也称作氧化亚氮( N2O) 是一种无色有甜味气体，在一定条件下能支持燃烧，但在室温下稳定，有轻微麻醉作用。
N2O 是京都议定书中规定控制的6 种温室气体之一，因此开发和利用好氧化亚氮产品，减少温室气体排放是长期需要研究的课题。
1 用途
医疗：氧化亚氮是人类最早应用于医疗的麻醉剂之一，早期被用于牙科手术的麻醉，现在外科手术、牙科麻醉等方面仍有应用。
食品：2015 年1 月国家卫生计生委批准了氧化亚氮为食品添加剂新品种，适用范围限定在“稀奶油( 淡奶油) 及其类似品的加工工艺”，奶油中添加了“氧化亚氮”之后，就会膨胀可塑，而且入口细腻。
电子产品生产：高纯氧化亚氮被更多地应用到微电子、光电子产品器件的生产过程中。在 IC( 半导体) 和LED( 发光二级管) 芯片的制作过程中，氧化亚氮作为其中的一种特气，经化学反应生成的SiO2膜被沉淀到硅衬底上，作为缓冲层阻止有害杂质的进入。氧化亚氮纯度影响到SiO2膜纯度，并最终影响到电子器件性能的好坏。因此这一领域对高纯氧化亚氮的需求在近几年将呈现持续增长，而且随着晶圆尺寸的升级换代，对高纯氧化亚氮产品质量的要求也越来越高。
在平板显示领域，目前薄膜晶体管占据主流显示器市场80% 以上的份额，有机发光二极管生产出的显示屏已应用到高端产品中。氧化亚氮在这两种显示器的制作过程中起到了至关重要的作用。显示器平板上形成的绝缘保护膜SiNx以前用氨气和硅烷反应来生成，现在越来越多地用氧化亚氮与氧化硅的反应来实现。
在太阳能光伏产业中，目前应用最广的是晶硅太阳能电池，在晶体硅电池片生产中的扩散工艺和刻蚀工艺中用到电子特气。
火箭推进剂和赛车加速：氧化亚氮基复合推进剂具有无毒、高比冲、使用系统简单等诸多优异性能，有望替代传统类推进剂用于多种航天器。在目前直线加速赛中，为了在瞬间提高发动机功率，利用的液态氮氧化物系统正是NOS。NOS 的工作原理是把N2O 形成高压的液态后装入钢瓶中，然后在发动机内与空气一道充当助燃剂与燃料混合燃烧N2O 可放出氧气和氮气，其中氧气就是关键的助燃气体，而氮气又可协助降温，以此增加燃料燃烧的完整度提升动力。
另外：氧化亚氮也可以用做检漏剂、制冷剂、防腐剂以及用作原子吸收光谱用的助燃剂。在工业上，用于地下的真空和带压管路的泄漏检测; 在实验室里，N2O 和C2H2燃烧用于难溶元素的分析。纵观氧化亚氮的各种用途，目前业界普遍看好的仍是高纯氧化亚氮在电子信息化产品领域的使用，其在半导体芯片和液晶面板生产过程中所发挥的独特的作用必将使其迎来一段快速发展的大好时期。
2 生产工艺
国内外生产氧化亚氮的方法主要是硝酸铵热分解法和混合气净化法。
硝酸铵热分解法：该方法是以硝酸铵为原料，通过高温分解产生工业氧化亚氮，然后将工业氧化亚氮分离提纯获得高纯氧化亚氮。
主要工艺流程: 颗粒状硝酸铵倒入融化锅的加料槽内，加入少量水和催化剂( 磷酸氢二铵) 加热，使其熔化，由注入泵注入到反应器。在反应器中分解的产物进入冷凝器、预洗器。在预洗器中反应物中的水蒸气冷凝成水，随同喷淋冷却水一同排出。反应物中水溶性杂质和机械杂质也被洗出。已除去大量水蒸气的气体进入净化系统。含有微量NO、NO2
和NH3的N2O 经净化塔水洗、碱洗、酸洗得到纯度为99% 的一氧化二氮，进入储气柜;
再由压缩机将其加压到5 ～ 8 MPa，通过高效水分离器分离除去压缩后的过饱和游离水，进入吸附干燥器进行干燥; 干燥气体在有水冷的高压冷凝器中液化为液体的一氧化二氮。
硝酸铵热分解法种方法生产工艺简单、质量较好，以往几乎占据了整个高纯氧化亚氮产品市场，该技术进口设备价格不菲，但目前技术已被国内专家突破，可以国产替代。但由于硝酸铵对热敏感，稍不慎将发生爆炸事故，因此要求控温很严; 另外该法中使用的原料硝酸铵为危险化学品，储存和生产过程中存在较大的安全隐患。再加之成本因素，该法生存空间将会越来越小。
尼龙单体工业尾气回收提纯工艺：在尼龙的生产过程中会产生富含氧化亚氮的工业尾气，如硝酸和己二酸生产过程中所产生的尾气，选用直接脱除的处理方法虽然可以满足环保要求，却也是一种对潜在资源的浪费。因此从尾气中回收提纯高纯氧化亚氮技术已经引起较多关注，多家企业已经或正在实现了工业化生产，经验证，从尾气中提纯出的高纯氧化亚氮产品质量完全可以替代硝酸铵法生产的高纯氧化亚氮，这种工艺由于其成本较低、生产工艺更绿色环保，正在逐步占据氧化亚氮产品大部分市场。
其他方法：如日本曾经采用过的尿素法、氮磺酸法、氨催化氧化法等，目前工艺化生产中已很少采用。
3 展望
电子气体纯度每提高一个数量级，都会极大的推动电子器件质的飞跃。氧化亚氮作为一种电子特气，正渐渐走进越来越多人的视线，发展前景看好。
目前尾气回收提纯高纯氧化亚氮产品已工业化量产，2023年国内产能还将还将大幅增长，加上国家“O2专项”计划的支持，氧化亚氮将成为国内首批特气国产化的高纯电子气体之一。此篇内容由平煤神马史先生文章为基础，特此感谢!
The function, manufacturing and prospect of nitrous oxide (N2O)
(based on Mr.Shi’s article , translated by Tianjin Summit Special Gases)
Nitrous Oxide, with its formula as N2O, is a kind of gas with sweet odor but not color. It can , on some conditions, support the combustion. General is stable and slightly anaesthetic.
N2O is one of the six green-house gases to be controlled stipulated in Kyoto Protocol, and therefore is a long-term subject of study in the field of exploration, exploitation for the reduction of green house gases.
1 Application
Medication: nitrous oxide is one of earliest anaesthetics used by the human beings in the medical realm, and by now still used in the surgical and dental operation based on its anaesthetic
Food: The national health & family planning commission approved the nitrous oxide as a new type of food additive, with its application limited to the “process of diluted cream, thin cream or its likes as the cream will be expandable and operational to the degree of tasting more smoothly.
Manufacturing of Electronic Parts: The nitrous oxide is used more and more in the process of manufacturing the micro-electronic and optical photoelectrons. In the process of production of integrated circuit (IC)and light emitting diode (LED), N2O, as a kind of special gases, silicon dioxide (SiO2) turned out through the chemical reaction is deposited to the silicon substrate to prevent the harmful impurities from entering. The purity of N2O is to affect the membrane purity of SiO2, further more bring the negative effect to the end electronic components. The demand on the nitrous oxide from this industry in on the rise steadily over the past few years. With the upgrading of chip sizes, the demand on the quality of nitrous oxide is more stricter.
In the field of panel display, more than 80% of the market is taken by thin film transistor, and the organic lighting diode is also put into production for the high end uses while the nitrous oxide plays an important role in the above processes. The insulated membrane of the panel displayer, i.e., silicon nitride previous made by reaction of ammonia and silane, now phased out with the replacement of reaction of nitrous and silicon dioxide. In the photovoltaic industry the mainstream process is the crystalline silicon cell, using this special gas in its etching and diffusion.
Rocket propellant and racing car acceleration：composite propellant based on based is of many advantages such as non-toxicity, high specific impulse and simple operation so that is the trend to replace the traditional propellants in various spacecrafts. In the drag racings of automobiles, NOS system makes use of liquid nitric oxide, which is of the high pressure liquid in gas cylinders, mixed with air in the engine, releasing nitrogen and oxygen after burning. The oxygen is the combustion supporting gas while the nitrogen helps the temperature decrease, thus the efficiency of combustion raised to boost the power.
In addition, the nitrous oxide is also used as leakage detection, refrigerant, preservative as well as the supportive agent of combustion in the atomic absorption spectrometer. In the industry, it is used to detect the leakage of underground piping and vacuum. N2O, matched with acetylene, is used in laboratory for the analysis of insoluble elements. In general, the best perspective of its quality use is still in the process of electronic products, i.e., the unique application in the manufacturing of semiconductor chips and liquid panel displayers will face a bright future of quick development.
2 Process of Plant Production
The main methods in China are the heating decomposition of ammonium nitrate, and chemical tail-gas purification.
Heating decomposition of ammonium nitrate: NH4NO3, decomposed into industrial grade N2O by way of heating, if necessary the high purity product can be obtained by further purification
Main Process: ammonium nitrate of granulation, dumped into the feed-tank of the melting vessel, with some quantity of water and diammonium hydrogen phosphate, a catalyst, supporting N2O’s dissolution before its pumping to the reactor by a injecting pump. All products in the reactor pushed to the condenser and pre-scrubber and the latter condenses the steam of all products into water and then discharged with the cooling water together. At the time all impurities of water-soluble and mechanical matters also washed away. The nitrous oxide while the water and steam excluded, is brought to the purification column, through the steps of water scrubbing, acid pickling, alkali wash, to eliminate the remaining nitric oxide, nitrogen dioxide, and ammonia. The product of 99% transmitted to the gas storage, compressed to a pressure up to5~8 megapascal (MPa) to get rid of the over-saturate free water due to the compression by means of high efficiency water separator, then dried in the adsorption and drying unit. The dried gas is liquified to the liquid N2O in the succedent high pressure condenser.
The decomposition of ammonium nitrate is of simple process, and better quality, dominating the high purity market of the gas. But the price of the imported equipment is not inexpensive. Fortunately the technique has already been studied and mastered by some experts in China and domestic equipment can be a good substitution. In addition, the ammonium nitrate is quite sensitive to the heat, a potential source of explosion if not handled carefully in terms of its temperature control. The ammonium nitrate, itself also a chemical material of danger, pose some unforeseen risks in the storage and operation, is finding its way not of wide perspective plus the consideration of purchase cost.
Recovery and Purification from Nylon Monomer: N2O rich gas turned out in the production of nylon such as in the processes of nitric acid and adipic acid. The direct scrubbing satisfied the environmental stipulation but also cause the waste of some potential resource. Therefore the recovery technology of nitrous oxide from the tail gas becomes the highlight of the industry. It is proved by the enterprises which have completed the production, that the quality of nitrous oxide is fully capable of replacing the high purity gas from the ammonium nitrate. Because of the low cost and more environment-friendly process, it is taking the market share drastically.
Other Methods: Some companies in Japan once take the urea treatment, aminosulfonic way, ammonia catalyze-oxidation., which are rarely used today.
3 Outlook
Each step upgraded in the electronic gas purity, will result in the quality leap of electronic components, and the nitrous oxide, as a newcomer in the electronic gases, is looked upon well by the related industries.
By now, the tail-gas recovery of nitrous oxide is in full swing with large amount turned out and the production is the year 2023 meets its new peak. With the account of governmental support in its decicated funds, the nitrous oxide will surely become the wholly china-make electronic gas.
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又讯：
2023-8-28蓝能公司官网消息，近日，公司自主研发的笑气长管拖车首次出口海外。笑气长管拖车是浙江蓝能特种气体储运装备系列产品之一，这次出口海外的工艺和质量达到国际先进水平。
笑气的化学名称是氧化亚氮（N2O），也叫作一氧化二氮，无色的可燃气体，略带甜味，没有刺激性，具有轻度麻醉作用。笑气是重要的工业气体和医疗气体，也是一种食品添加剂。但由于笑气是易燃的危险化学品，同时人体吸入后在体内的弥散速度很快，容易引发缺氧窒息，所以国内外对笑气包装容器的安全性、密封性要求极高。浙江蓝能在吸收国内外先进技术的基础上，自主研发了高标准的笑气储运装备，并达到量产条件。
manufacturing-of-high-purity-nitrous-oxide-written-by-GAO-T.L
