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工业固氮和共生固氮的比较

已有 13855 次阅读 2008-1-1 19:30 |个人分类:科研工作|系统分类:科研笔记

工业固氮生产化肥:

耗费大量的化石燃料,产生了大量的二氧化碳,不仅耗能,而且产生了大量的温室气体。反应过程是在高温高压,并且需要催化剂的存在下才能进行。将空气中的氮气合成为氨。

下面是哈珀工业上合成氨的故事,找了好久才找到,转贴一下(来自:http://dxchong.bokee.com/6102059.html

        在化学发展史上,有一位化学家,虽早已长眠地下,却曾给世入留下过关于他的功过是非的激烈争论。他就是本世纪初世界闻名的德国物理化学家、合成氨的发明者弗里茨•哈伯(Fritz Haber)。 

        赞扬哈伯的人说:他是天使,为人类带来丰收和喜悦,是用空气制造面包的圣人;诅咒他的人说:他是魔鬼,给人类带来灾难、痛苦和死亡,针锋相对、截然不同的评价,同指一人而言,令人愕然;哈伯的功过是非究竟如何,且看这位化学家一生所走过的辉煌而又坎坷的道路。 
    1868年12月9日哈伯出生于西里西亚的布雷斯劳(现为波兰的弗罗茨瓦夫),父亲是知识丰富又善经营的犹太染料商人,耳闻目睹,家庭环境的熏陶使他从小和化学有缘。哈伯天资聪颖,好学好问好动手,小小年纪就掌握了不少化学知识,他曾先后到柏林、海德堡、苏黎世求学,做过著名化学家霍夫曼和本生的学生。大学毕业后在耶拿大学一度从事有机化学研究,撰写过轰动化学界的论文,哈伯19岁就破格被德国皇家工业大学授于博士学位,1896年在卡尔斯鲁厄工业大学当讲师,1901年哈伯和美丽贤慧的克拉克小组结为伉俪。1906年起哈伯任物理化学和电化学教授。 

    19世纪末化肥工业的出现和发展推动了农业生产的发展。随着世界人口增长对粮食的需求也日趋增大,再加上工业发展和军事上的迫切需要,使人工固氮在本世纪初成了世界性的重大研究课题。仅管不少化学家耗费了相当大的精力,但仍未掌握一种较理想的人工固氮方法。 
    1905年哈伯赴美国考察,回国后也采用高压放电固氮,实验历时一年效果不尽人意。后来从法国化学家用高温、高压合成氨发生爆炸的消息中获得启示,他也毅然采用该法进行试验,表现了他的果断和勇气。在历经无数次失败后,  1909年7月2日哈伯在实验室采用600℃、  200个大气压和用金属铁作催化剂的条件下,人工固氮成功,平衡后氨的浓度达到6%,首次取得突破,当年德国巴登苯胺纯碱公司总经理、工业化学家博施(Carl  Bosch),参观了哈伯的实验室,确认他的方法成功、有效,决定扩大进行中间试验。此后哈伯提出了原料气循环使用的合理建议;博施也解决了从水煤气中获得氢气的问题。1910年建成新工艺流程的中试工厂。该公司的研究人员在化学家米塔斯(Mitas)的主持下,用2500种不同的催化剂经上万次试验,终于研制成功含有钾、铝氧化物作助催化剂的价廉易得的高效铁催化剂。1911年巴登公司在德国奥堡建成世界第一座日产30 吨合成氨的工厂。人称这种合成氨方法为“哈伯-博施法”,这是具有世界意义的人工固氮技术的重大成就。是化工生产实现高温、高压、催化反应的第一个里程碑。合成氨的原料来自空气、煤和水,因此是最经济的人工固氮法,从而结束了人类完全依靠天然氮肥的历史,给世界农业发展带来了福音;为工业生产、军工需要的大量硝酸、炸药解决了原料问题)在化工生产上推动了高温、高压、催化剂等一系列的技术进步。合成氨的成功也为德国节省了巨额经费支出,哈伯、博施也一举成名。 
        作为合成氨工业的奠基人,哈伯也深受当时德国统治者的青睐,他数次被德皇威廉二世召见,委以重任。1911年他担任了威廉皇家物理化学和电化学研究所所长兼柏林大学教授。1914年第一次世界大战爆发时,哈伯参与设计的多家合成氨工厂已在德国建成。当时唯有德国掌握垄断了合成氨技术,这也促成了德皇威廉二世的开战决心。威廉认为只要能源源不断地生产出氨和硝酸,德国的粮食和炸药供应就有保证:再全力阻扰敌国获得智利硝石就可以制限对方,德国就能获胜。外国首脑和军事专家也曾预测:由于含氨化合物的短缺,大战将在一年之内结束。不料德国合成氨的成功使其含氮化合物自给有余,从而延长了一次大战的时间,哈伯的成功也给平民百姓带来了灾难、战争和死亡,这大概是他料想不到的。

关于哈珀的英文介绍(以下资料及照片均来自http://nobelprize.org/nobel_prizes/chemistry/laureates/1918/haber-bio.html):

 

Fritz Haber was born on December 9, 1868 in Breslau, Germany, in one of the oldest families of the town, as the son of Siegfried Haber, a merchant. He went to school at the St. Elizabeth classical school at Breslau and he did, even while he was at school, many chemical experiments.

From 1886 until 1891 he studied chemistry at the University of Heidelberg under Bunsen, at the University of Berlin under A.W. Hoffmann, and at the Technical School at Charlottenburg under Liebermann. After completing his University studies he voluntarily worked for a time in his father's chemical business and, being interested in chemical technology, he also worked for a while under Professor Georg Lunge at the Institute of Technology at Zurich. He then finally decided to take up a scientific career and went for one and a half years to work with Ludwig Knorr at Jena, publishing with him a joint paper on diacetosuccinic ester. Still uncertain whether to devote himself to chemistry or physics, he was offered in 1894, and accepted, an assistantship at Karlsruhe by the Professor of Chemical Technology there, Hans Bunte. Here he remained until 1911. Bunte was especially interested in combustion chemistry and Carl Engler, who was also there, introduced Haber to the study of petroleum and Haber's subsequent work was greatly influenced by these two colleagues.

In 1896 Haber qualified as a Privatdozent with a thesis on his experimental studies of the decomposition and combustion of hydrocarbons and in 1906 he was appointed Professor of Physical Chemistry and Electrochemistry and Director of the Institute established at Karlsruhe to study these subjects.

In 1911 he was appointed to succeed Engler as Director of the Institute for Physical and Electrochemistry at Berlin-Dahlem, where he remained until, in 1933, the Nazi race laws compelled nearly all his staff to resign and Haber, rather than agree to this, himself resigned. He was then invited by Sir William Pope to go to Cambridge, England and there he remained for a while. He had, however, been suffering for some time from heart disease and, fearing the English winter, he moved to Switzerland.

Haber's early work on the decomposition and combustion of hydrocarbons has already been mentioned.

In 1898 Haber published his textbook on Electrochemistry, which was based on the lectures he gave at Karlsruhe. In the preface to his book he expressed his intention to relate chemical research to industrial processes and in the same year he reported the results of his work on electrolytic oxidation and reduction, in which he showed that definite reduction products can result if the potential at the cathode is kept constant. In 1898 he explained the reduction of nitrobenzene in stages at the cathode and this became the model for other similar reduction processes.

There followed, during the next ten years, many other electrochemical researches. Among these was his work on the electrolysis of solid salts (1904), on the establishment of the quinone-hydroquinone equilibrium at the cathode, which laid the foundations for Biilmann's quinhydrone electrode for determining the acidity of a liquid; but Haber invented, in collaboration with Cremer, the glass electrode for the same purposes which is now widely used. This led Haber to make the first experimental investigations of the potential differences that occur between solid electrolytes and their aqueous solutions, which were of great interest to physiologists.

During this period Haber also studied the loss of energy by steam engines, turbines and motors driven by fuels, and sought methods of limiting their loss by electrochemical means. He did not succeed in finding a solution of this problem that was commercially applicable, but he did succeed in finding a fundamental solution for the laboratory combustion of carbon monoxide and hydrogen.

He then turned to the study of flames and did fundamental researches on the Bunsen flame, showing that, in the luminous inner cone of this flame, a thermodynamic water-gas equilibrium is established and that, in its outer mantle, there is combustion of water-gas. This led to a chemical method of determining flame temperatures.

Haber then undertook the work on the fixation of nitrogen from the air for which he was given the Nobel Prize in Chemistry for 1918 (awarded in 1919).

In 1905 he had published his book on the thermodynamics of technical gas reactions, in which he recorded the production of small amounts of ammonia from N2 and H2 at a temperature of 1000° C with the help of iron as a catalyst. Later he decided to attempt the synthesis of ammonia and this he accomplished after searches for suitable catalysts, by circulating nitrogen and hydrogen over the catalyst at a pressure of 150-200 atmospheres at a temperature of about 500° C. This resulted in the establishment, with the cooperation of Bosch and Mittasch, of the Oppau and Leuna Ammonia Works, which enabled Germany to prolong the First World War when, in 1914, her supplies of nitrates for making explosives had failed. Modifications of this Haber process also provided ammonium sulphate for use as a fertilizer for the soil. The principle used for this process and the subsequent development of the control of catalytic reactions at high pressures and temperatures, led to the synthesis of methyl alcohol by Alwin Mittasch and to the hydrogenation of coal by the method of Bergius and the production of nitric acid.

During the years between the two World Wars Haber produced his firedamp whistle for the protection of miners, his quartz thread manometer for low gas pressures and his observation that adsorption powers can be due to unsaturated valence forces of a solid body, on which
Langmuir founded his theory of adsorption. When the First World War broke out he was appointed a consultant to the German War Office and organised gas attacks and defences against them. This and other work undermined his health and for some time he was engaged in administrative work. He helped to create the German Relief Organisation and served on the League of Nations Committee on Chemical Warfare.

From 1920 until 1926 he experimented on the recovery of gold from sea water, his idea being to enable Germany to meet her war reparations. Greatly depressed by the failure of this project, which he attributed to his own deficiency, he devoted himself to the reorganisation of his Institute, to which he appointed sectional directors with complete freedom in their work. Among these were James Franck, Herbert Freundlich, Michael Polanyi and Rudolf Ladenburg; from the Institute came much work on colloid chemistry and atomic physics. Haber himself, at this time, made great efforts to re-establish the scientific relationships of Germany with other countries and the colloquia which he held every fortnight did much to establish the international repute of his Institute. During his last years he worked on chain reactions and on mechanisms of oxidation and on hydrogen peroxide catalysis.

Haber lived for science, both for its own sake and also for the influence it has in moulding human life and human culture and civilization. Versatile in his talents, he possessed an astonishing knowledge of politics, history, economics, science and industry and he might have succeeded equally well in other fields. The hesitation with which he finally decided to be a chemist has already been mentioned. He welcomed administrative responsibilities in addition to research work. Always approachable and courteous, he was interested in every kind of problem. His ability to clarify, in a few sentences, the obscurities of a scientific discussion, was a valuable feature of the colloquia he held at his Institute and his organising talent made him a model Director of a large establishment in which he allowed complete freedom, to the workers under him, maintaining, nevertheless, a remarkable control over the activities of the Institute as a whole. A man of forceful personality, he left a lasting impression on the minds of all his associates.

Apart from the Nobel Prize, Haber received many honours during his life. At Max von Laue's instigation, the Institute for Physical and Electrochemistry at Berlin-Dahlem was renamed the Fritz Haber Institute after his death.

After a grave illness, Haber died on January 29, 1934, at Basle, on his way from England to convalesce in Switzerland, his spirit broken by his rejection by the Germany he had served so well.

共生固氮:

Hellriegel and Wilfarth (1888) later demonstrated that nitrogen fixation in legumes takes place by the active participation of microorganisms in root nodules. Since neither the plant nor the microorganism can fix nitrogen independently, the process has been called symbiotic nitrogen fixation.

The root nodule bacteria were isolated by Beijerinck in 1888, and were grouped in the genus Rhizobium (Rhizo means root in Greek). These are gram negative motile, aerobic, non spore forming bacteria. They are mainly rod shaped, but a variety of morphological shapes are observed on isolation from nodules.

(以上英文材料来自:http://www.microbiologyprocedure.com/nitrogen-fixation/legume-rhizobium-system.htm

对于根瘤菌-豆科植物这一共生固氮体系来说,植物利用太阳能为能源,通过光合作用吸收二氧化碳,根瘤菌通过固定空气中氮为氨为植物提供氮素营养。这一过程是在常温常压下进行的。

“对于人类来说,利用根瘤菌固氮不花费任何工程,不花费一分钱,就能直接将大气中的氮气转化为人类需要的各种氮源。”(这句话引自http://zhidao.baidu.com/question/39173067.html





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