Page 100 - Principles of Catalyst Development
P. 100

DESIGN  OF  CATALYSTS                                            87
            CH 4  + O2 = CH2 0  + H20        01, DH,O       -70.9 kcal mole-  1
                      = HCOOH + H2           01, DH,O       -67.0
                      =  CO + H2 + H2 0      OI,DH,O        -87.3
                      = CO2  + 2H2           01, DH,O       -90.5
            CH 4 + ~02 = CH20  + H2 0 2      OI,DH,O        -31.0
                      = HCOOH + H2 0         01, DH, 0     -119.8
                      = CO + 2H 20           01, DH,O      -136.5
                      = CO2  + H2 + H20      OI,CH,O       -139.8
                                             OI,DH,O        -98.6
            CH 4 + 20 2  = HCOOH + H2 0 2
                      = CO + H 20 2 + H 20   01, DH,O      -118.7
                      = CO 2 + 2H 20         01, DH,O      -189.5
                Reactant - Product  Reactions:

               CH 4  + C2H6  = C)Hs + H2     DH,A             16.6
               CH 4 + C2H4  = C3 HS          A                 4.5
            CH 4  + CH)OH  = C2HsOH + H2     DH,A             10.5


                  !02 + H2  =  H2 0          01             -50.3
                ~02 + C2H6  = C2HsOH         01             -30.7
               !02 + CHzO =  HCOOH           01             -45.3

                                             0               -9.2


            5.2.2.  Thermodynamic Analysis

                The objectives in this step are to assess thermodynamic feasibility for
            each  of the  stoichiometric  equations  and  to  list  them  in  groups  with  the
            same  chemical  functions.  For  clarity,  many  intermediate  reactions  have
            been omitted from  the  rearrangements  below.  Reactions  with  aG~ values
            greater than  10 kcal mole- are not included at this point.
                                   1
                  CH 4 + 202 =  CO2  + 2HzO      OI,DH,O        -189
                   CH 4 + O2 =  CH2 0  + H 2O    01, DH,O        -70
                   CH 4 + O2  =  HCOOH + H2      OI,DH           -67
                  CH 4 + ~02 =  CH 20  + H2      OI,DH           -20
                  CH 4  + 102 = CH 30H           01              -22
                      CH 20  =  CO + H2          DH              -17
                    CH 30H = CHzO + Hz           DH                2

                At  this  stage,  the  reactions  are  examined  for  common  trends.  For
           example,  the  target  reaction  is  in  the  same  grouping  as  combustion  or
           oxidation. Attempts to build these functions into the catalyst result in poor
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