×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Ammonia and graphite interaction

Ammonia and graphite interaction

Ammonia and graphite interaction

(OP)
Does anyone know what is the interaction between ammonia and graphite at 800-1200 C under 100-400 torr?

RE: Ammonia and graphite interaction

One thermodynamically possible reaction is ammonia decomposition/methane formation:

4 NH3 + 3 C(gr.) --> 2 N2 + 3 CH4     delta GRxn,298K = -20.6 kcal/mol

As there is an increase in gas volume associated with this rxn., it should be favored by the reduced pressure.

RE: Ammonia and graphite interaction

There are several CxNyHz compounds, but they don't seem thermodynamically likely, i.e., have delta Gf > 0.

Take a look at the thermo data for 25o in Perry's, 6th Edn. p. 3-149.  I don't believe that the increase in T will make a qualitative change.  Most of the CxNyHz compounds will thermally decompose, especially with a solid surface to catalyze the reaction.

RE: Ammonia and graphite interaction

Although ammonia is expected to be at least partly dissociated in the absence of catalysts, books say that with carbon, at read heat, ammonia reacts to give ammonium cyanide.

RE: Ammonia and graphite interaction

(OP)
Thank you for the responses so far, what I observed in my reactor systems are, the porous solid graphite turns into powderly carbon compound.  This could be that the graphite is slowly decomposing according to reaction:
4 NH3 + 3 C(gr.) --> 2 N2 + 3 CH4     delta GRxn,298K = -20.6 kcal/mol
The graphite as it looses methane it become more porous and began to collapse.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources