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Contents contributed and discussions participated by Alexa Wisniarek

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Alexa Wisniarek

The Haber Process - Nitrogen Fertilizer from the Air - 1 views

www.the-compost-gardener.com/haber-process.html

shared by Alexa Wisniarek on 14 Feb 13 - No Cached
  • The Haber Process
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Why is it usually only know as the Haber Process?
  • high pressures and temperatures
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      To shift the equilibrium towards the side that produces Ammonia and to make it so the reaction doesn't take an extremely long time to happen.
  • the lack of fixed nitrogen is often the limiting factor in an ecosystem or for crops.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      I never would have thought of that. Interesting to find out.
  • ...4 more annotations...
  • By the end of the 19th century these sources of fixed ntrogen were running out. Scientists were challenged to come up with a process of making fixe
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      How could these things run out?
  • the process and Carl Bosch was charged with upscaling it to factory size, a feat he managed by 1913.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Why he's also mentioned in the name of the process sometimes.
  • Between 500 and 600 were killed and 2000 injured.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      That's really sad...
  • We convert more N2 gas into fixed reactive forms than all the Earth's processes combined. Synthetic nitrogen fertilizer production, vehicle exhaust emissions and e
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      That's a little shocking.
Alexa Wisniarek

Researchers Gain Insight into Hundred-Year-Old Haber-Bosch Process : Rochester News - 1 views

www.rochester.edu/...show.php

shared by Alexa Wisniarek on 14 Feb 13 - No Cached
  • hile they're abundant in the air around us, which makes them desirable for research and manufacturing, their strong triple bonds are difficult to break, making them highly unreactive.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Interesting. Good to know for future units.
  • For the last century, the Haber-Bosch process has made use of an iron catalyst at extremely high pressures and high temperatures to break those bonds and produce ammonia, one drop at a time
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Except for the high temperature, this all fits with equilibrium. The high temperature is used to make a faster rate of reaction.
  • "The Haber-Bosch process is efficient, but it is hard to understand because the reaction occurs only on a solid catalyst, which is difficult to study directly,
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Why is that difficult to study?
  • ...4 more annotations...
  • They discovered that an iron complex combined with potassium was capable of breaking the strong bonds between the nitrogen (N) atoms and forming a complex with an Fe3N2 core, which indicates that three iron (Fe) atoms work together in order to break the N-N bonds. The new complex then reacts with hydrogen (H2) and acid to form ammonia (NH3)—something that had never been done by iron in solution before.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Why does this occur that way and why has it never occured before? Interesting that they find out more about the mechanism after so long.
  • While there are risks in producing ammonia at extremely high temperatures and pressures, Holland points out that the catalyst used in Haber-Bosch is considerably less expensive than what was used by his team
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      It doesn't seem like they need to shift the equilibrium or speed up the reaction with the other catalyst.
  • Holland says the nitrides formed in solution could be useful in making pharmaceuticals and other products.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Integrating different areas of study in science. Also, how would Ammonia be used to make pharmaceuticals?
  • scientists have had little understanding of how it actually works.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Why haven't they studied it more? Do they more or less just take for granted the fact that it works?
Alexa Wisniarek

Gale Science In Context - Document - 14 views

ic.galegroup.com/...DocumentToolsPortletWindow

shared by Alexa Wisniarek on 14 Feb 13 - No Cached
  • by high-pressure catalytic reactions of nitrogen (from air) with hydrogen.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Using pressure to shift the equilibrium.
  • Ammonium nitrate is used as a high explosive; ammonium perchlorate is a component of rocket fuels.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      It's used for both "good purposes", like fertilizer, and "bad" purposes, like weapons.
  • (The ammonia occupies less volume than the gases from which it is made.) High pressure conditions (150-250 bar) are used, and temperatures range from 752-932°F (400-500°C). The mixed gases circulate through the catalyst, ammonia is formed and removed, and the unconverted reactants are recirculated.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      High pressure. High temperature, even though there would be more Ammonia production at low temeperature, to speed up the rate of reaction.
  • ...3 more annotations...
  • The gases that enter the catalytic converter must be highly purified and free of sulfur compounds, which adversely affect the catalyst.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Interesting that sulfur adversely affects the catalyst.
  • These bacteria and algae possess an enzyme called nitrogenase that permits them to convert nitrogen to ammonia at 77°F (25°C) and 1 bar of pressure, much milder conditions than those of the Haber-Bosch process.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Really interesting and neat that they can do that.
  • , as the nations evolve toward alternative fuels.
    • Alexa Wisniarek
      Alexa Wisniarek on 14 Feb 13
       
      Will Ammonia change the transportation of the future?
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