Solid catalyst selection for formaldehyde synthesis by methane oxidatio

Budininkas, P.

Ferris, R. W.

Remus, G. A.

English

NASA Technical Reports Server

3 RESEARCH AND DENELOPMFNT STUDY 
RELATED TO THE SYNTHESIS OF 
FOFWALDEKYDE FR0M;COp AlTDgFIp q c - 
GARD Project 1416 
6 P. Budininkas 
R. W. Ferr i s  
G. A.  Rems q 
Fer ARC Technical Monitor 
NAS2-3889 - Z?t.\l 
National Aeronautics and Space Administrat,ion 
Ames Research Center 
Moffett Field,  Cal i fornia  
GENERAL AMERICAN RESEARCH PIVISION 
https://ntrs.nasa.gov/search.jsp?R=19670012845 2020-03-16T18:02:20+00:00Z
Quarterly Progress Report No. 2 
SYIWHESIS OF FORMALDEHYOE 
Introduet ion 
This report  summarizes the  a c t i v i t i e s  of t he  General American Research 
Division during November 1966 through January 1967 on Contract NAS2-3889, 
Synthesis of Fomaldehyde. 
cerned with (1) select ion of so l id  ca ta lys t s  and a cor re la t ion  of t h e i r  
a c t i v i t i e s  for t h e  oxidation of methane t o  formaldehyde with t h e i r  chemical 
and physical properties,  ( 2 )  construction of an experimental system f o r  
E t h a n e  oxidation t o  formaldehyde and the development of experimental pro- 
cedures, and ( 3 )  t e s t i n g  so l id  ca ta lys t s  and invest igat ing the  e f f ec t s  of 
var iables  such as temperature, feed gas composition, and space veloci ty  on 
the  y i e l d s  of formaldehydea 
The a c t i v i t i e s  during t h i s  quar te r  were con- 
The best  r e su l t s  were obtained using an etehed s i l i c a  tube as the  
ca ta lys t  with a maximum formaldehyde yield ranging up t o  0.7% of t h e  methane 
i n  t h e  feed gas. 
1. Seleet ion of Sol id  Catalysts 
The l i t e r a t u r e  survey revealed a considerable number o f  metals and metal 
oxides which have been elaimed as ca ta lys t s  f o r  t he  oxidation of methane t o  
Eormaidehyde. Table 1 pressnks the  sol id  ca t a lys t s  arranged according t o  
t h e  frequency of t h e i r  appearan2e i n  published yepol-ts. 
temperatures with these ca ta lys t s  range from 330" t o  l,OOO°C, usually being 
500 - 600"c. Although elemental metal ca ta lys t s  a r e  claimed, it i s  improbable 
a t  these temperatures and i n  the  presence of oxygen t h a t  elemental surfaces 
The reported react ion 
ERAL AMERIGAN RESEARCH PIVISION 
1 
were present, except i n  t h e  cases of Au, Ag, and t h e  Platinum Group metals. (1) 
Therefore, it appears that t h e  r ea l  ca t a ly t i c  surfaces were oxides o r  oxide 
f i l m s .  
Table 1. CATaYSTS FOR THE PRODUCTION OF CH20 FROM CH4 
W N G E D  ACCORDING TO THE FREQUENCY OF APPEARANCE IN PUBLISHED FXPOFX’S 
Attempts were made t o  cor re la te  the a c t i v i t f e s  of t he  so l id  ca ta lys t s  
used f o r  t h e  conversion of methane t o  formaldehyde with t h e i r  chemical 
and. physical p r o p i r t i e s .  Some of the properties of oxides cl-aimed most 
frequently as ca ta lys t s  a re  given i n  Table 2. Although most of these metals 
are capable of forming several  oxides, the  l i t e r a t u r e  shows l i t t l e  indicat ion 
which oxides were used; therefore ,  data on the  more common regular oxides 
a r e  given. 
None of the  proposed s o l i d  ca ta lys t s  exhibi t  an outstanding a c t i v i t y  
f o r  t h e  conversion of methane t o  fopmaldehyde. The ca t a ly t i c  a c t i v i t i e s  
of metal oxides l i s t e d  i n  Table 2 do not ind ica te  any general trends or  
1. G. C .  Bond, “Catalysis by Metals,” Academic Press? Inc.,, London, 1962, 
G E N E R A L  A M E R I C A N  R E S E A R C H  P I V l 5 l D N  
0 
(u 
0 
cu 
CA 
rl 
c 
- 
c 
GENERAL AMERICAN RESEARCH PIVISION 
3 
corre la t ion  with t h e i r  chemical and physical propert ies .  
t h i s  behavior can be explained by t h e  r e l a t ive ly  high react ion temperatures 
used with a l l  these ca ta lys t s .  
a large port ion of t h e  formaldehyde formed i s  oxidized fu r the r  t o  C02. Besides, 
a t  increasinp react ion temperatures formaldehyde becomes unstable and decomposes 
appreciably. 
rates of formation and of destruct ion during t h e  process. 
formaldehyde depends not only on t h e  a c t i v i t y  of t he  ca ta lys t  but  a l s o  on t h e  
effectiveness of t h e  measures employed f o r  t h e  prevention of t h e  destruct ion 
of formed formaldehyde, such as increased space velocity,  immediate quenching, 
o r  absorption of t h e  product. 
ca ta lys t  becomes masked by these other  e f f ec t s  and de f in i t e  a c t i v i t y  pat terns  
a r e  not readi ly  apparent e 
The reason f o r  
Since these oxides a r e  general  oxidation ca ta lys t s ,  
Therefore, t he  reported yields  of formaldehyde depend both on t h e  
The production of 
The resu l t  i s  tha t  t he  true a c t i v i t y  of a 
From a p rac t i ca l  viewpoint, t h e  nuniber of appearance i n  patent claims 
and publ icat ions can be considered as some indicat ion of t h e  s u i t a b i l i t y  of 
a ca t a lys t .  
using various so l id  ca t a lys t s  a r e  of approximately the  same order? it can be 
expected t h a t  ca ta lys t s  which give somewhat b e t t e r  r e s u l t s  would receive more 
a t t e n t i o n  and would be described more frequently i n  the  l i t e r a t u r e .  There- 
fore,  t h e  arrangement of so l id  ca ta lys t s  i n  Table 1 can serve as a s t a r t i ng  
point i n  t h e i r  evaluation. 
Although t h e  y ie lds  of formaldehyde from t he  oxidation-of methane 
2. Experimental System and Procedures 
An experimental system f o r  the  production of formaldehyde from methane 
which i s  su i tab le  f o r  use with both sol id  and gaseous ca ta lys t s  i s  shown 
schematically i n  Figure 1. The actual  reactor  consis ts  of a Vycor g lass  
tube, 18" long, having a 23 mm. inside diameter. A four-inch long reaction 
GENERAL AMERICAN RESEARCH PlVlSlON 
4 
I 
zone i s  heated t o  t h e  desired temperature by an e l e c t r i c  heater surrounding 
the  Vycor tube. A movable thermocouple permits measurement of t he  tempera- 
t u r e  a t  various l eve l s  of t he  react ion zone. When t e s t i n g  so l id  ca ta lys t s ,  
a ca ta lys t  bed of known volume i s  located i n  the  center of t h e  react ion 
zone e 
Metered streams of oxygen and methane are premixed and f ed  in to  t h e  
reaction zone. 
analyzer and t h e  absolute rate of t o t a l  gas flow i s  determined from t h e  gas 
composition and oxygen flow measurements obtained with a mass flowmeter. 
The o;yygen concentration i s  monitored continuously by an oxygen 
The reac t ion  product i s  passed through a gas washing b o t t l e  containing 
a known mount of water where the condensables such as formaldehyde, methanol, 
and water vapor a re  absorbed. The amount of formaldehyde formed i s  determined 
from t h e  analysis  of t he  resu l t ing  solution. 
Sample por t s  permit sampling of the feed gases and of t h e  product from 
which t h e  condensables have been removed f o r  an accurate gas-chromatographic 
analysis  f o r  CH4> 02> C02, CO, N z 9  and H2. 
analyzers monitor t he  concentrations of C02 and CO i n  the  reaction product. 
Continuous non-dispersive infra-red 
To f a c i l i a t a t e  t h e  screening of  the  so l id  ca ta lys t s ,  runs of two hour 
duration a re  performed and the  concentration of fomldehyde  i n  t h e  condensate 
col lected i n  the gas wash b o t t l e  i s  determined by a colorimetric method using 
e i t h e r  a Nessler ' s  or a modified Schiff reagent. ( 2 )  O n l y  runs producing 
formaldehyde y i e lds  of a t  l e a s t  1% (y ie ld  = formaldehyde produced/methane 
i n  t h e  feed)  a r e  fu r the r  considered and a complete analysis  of t h e  feed and 
of t h e  product i s  then performed. 
2. J. F. Walker, "Formaldehyde", Third Edition, Reinhold Publishing Cor-p., 
New York, N.Y., 1964. 
GENERAL AMERICAN RESEARCH PfVlSlON 
5 
6 
A complete gas analysis  both of the feed gas and of t h e  react ion product 
i s  conveniently achieved by gas chromatographic techniques using a thermal 
conductivity detector .  
analyzed using a s i l i c a  g e l  column heated t o  90" - 110°C and a molecular 
sieve column a t  room temperature connected i n  ser ies .  
allows a separation of t h e  peaks f o r  H2, C02,  02> N2, COY and CH4* 
condensables (CH20, CH30H, and CHOOH) collected i n  water a r e  analyzed using a 
Porapak N Column heated t o  110" - 160"c. 
The feed gas and t h e  non-condensable p o d u c t s  a re  
This arrangement 
The 
3. Testing of Sol id  Catalysts 
The s u i t a b i l i t y  of so l id  cbtalysts  for the  production of formaldehyde 
f ron  methane has been t e s t ed  under various experimental conditions. 
a c t i v i t y  of each ca ta lys t  w a s  t e s t ed  at 800, 1,000, and 1,200"F using space 
ve loc i t i e s  of 450 hr-'> 900 hrol, and 1,200 hr-'. 
composition w a s  varied from 95$ 02 and 5% CH4 t o  10% 02 and 90% CH4; however, 
most of t h e  experiments were performed using a. feed consisting of 47.576 02 
and 52.5% CH4. 
The 
I n i t i a l l y ,  t h e  feed gas 
Certain oxygen - methane mixtures were found t o  be explosive under t h e  
The reported lower flammability l i m i t  of oxygen - experimental conditions. 
methane mixtures i s  5.4% CH4; t he  upper, 59% CH4. (3 )  However, t h e  tendency t o  
explode also appears t o  depend on t h e  temperature, t h e  composition, and the  flow 
r a t e .  The amount of energy input necessary t o  i n i t i a t e  an explosion i s  lowest 
for mixtures containing 25% of methane, but increases sharply with an increase 
i n  t h e  methane concentration. U s i n g  a react ion tube of 23 mm inside diameter, 
3. R. E. Kirk and D. F. Othmer, "Encyclopedia of Chemical Technology," Vol. 5, 
962, The Interscience Encyclopedia, Inc. , New York, N.Y ., , 1950 p. 
GENERAL AMERICAN RESEARCH DIVISION 
7 
mixtures containing a t  l e a s t  52.5% of methane do not explode even a t  flow 
r a t e s  as low as 100 zc/min. 
52.5% of methane can be used a t  high f l o w  r a t e s s  but tend t o  explode as t h e  flow 
r a t e  i s  lower2d. 
feed mixtures containing 52.5% or s l igh t ly  more of methane. 
A t  l j00O0F, gas feed mixtures containing less than 
Therefore, most of the experimfntai runs were performed with 
A sumnary of t h e  experimental results obtained with s o l i d  ca ta lys t s  
t e s t ed  t o  date i s  given i n  Table 3 .  
performed, only t h e  bes t  r e s u l t  achieved with each ca ta lys t  i s  l i s t e d .  
most e f fec t ive  ca ta lys t  w a s  found t o  be the etched w a l l s  of a Vycor g lass  
tube, producing up t o  a 0.78% yie ld  of formaldehyde. 
giving up t o  0.32% yields ,  while a l l  ot*her so l id  ca ta lys t s  produced only very 
small y ie lds  of fomldehyde .  
i n i t i a t e  a complete oxidat io  
With N i ,  Co, Zns and C r  oxides, t k . 2  complete oxidation already begins a t  8 0 0 " ~  
t o  such an extent t h a t  it causes flashing ( i . e .  formation of an intermit tent  
flame i n  t h e  reac tor )  i n  the  react ion tube and a runaway of temp- v a t u r e  . 
Although 70 separate t e s t s  have been 
The 
Tungsten oxide w a s  second 
With the  exception of s i l i c a ,  a l l  other ca t a lys t s  
P methane at  tcmperatures of 1,000"F and 1,200"F. 
4. Future Ac t iv i t i e s  
During t h e  next quarter,  experimental invest igat ion of formaldehyde 
production from methane w i l l  be continued by: 
a)  
b ) 
c )  
Further screening of so l id  ca ta lys t s  
Invest igat ion of nitrogen oxide ca ta lys t s  
Invest igat ion of t h e  use of ozone? as an addi t ive t o  oxygen alone 
and i n  conjunction w i t h  solid ca ta lys t s .  
GENERAL AMERICAN RESEARCH DIVISION 
8 
Table 3. SUMMARY OF FORMALDEKYDE PRODUCTION 
FROM METHANE USING SOLID CATALYSTS 
Active 
Ingredient 
Etched Si02 
Etched Si02 
Etched Si02 
Moo3 
V203 
&02 
Ni02 
Catalyst  
Description 
Etched w a l l  of t h e  Vycor 
react ion tube, 23 mm I . D . ,  
4" long 
Same as #1; tube f i l l e d  w i t 1  
6" O.D. etched Vycor tubes 
Same as #1; react ion zone 
f i l l e d  with etched s i l i c a  
boi l ing chips 
10% Moo3 on high a c t i v i t y  
alumina, Harshaw Mo-1201 
T 1/8 
10% V2O3 on high a c t i v i t y  
alumina, Harshaw v-0601 
T 1/8 
19% Mn02 on act ivated 
alumina, Harshaw Mn-0201 
T 1/8 
15% N i  i n  oxide form on 
act ivated alumina, Harshaw 
1% wo3 on act ivated 
alumina, Harshaw W-0101 
T 1/8 
Ni-0302 T 1/8 
39% Co on kieselguhr, 
Harshaw CO-0108 T l/8 
Highest 
Yield, * 
% 
0 78 
,002 
< ,002 
< .02 
< .02 
< .002 
< -002 
* 32 
< .002 
Remarks 
Flashing. Temp. 
control impossible. 
Flashing when 1100°F 
i s  reached. 
Stable  temp. 
impossible. 
*Yield = Moles of Formaldehyde Formed/ Moles of Methane i n  Feed. 
GENERAL AMERICAN RESEARCH DIVISION 
9 
Active 
Ing red i ent  
~ ~~ 
Zn oxide 
C r  oxide 
Cr oxide, 
Ba oxide 
N i  - W 
Catalyst 
De s cr ipt. ion 
24% Zn oxide on ac t iva ted  
alumina, Harshav Zn-0701 
T 1/8 
Cr oxide (Cr vi-iv-l on 
Crvi- iv 
ac t iva ted  alumina, FERLOX 
ca ta lys t  
oxidesg Ba oxide, 
Ba chromates on ac t iva ted  
alumina, CEELOX 8615 
ca t a lys t  
6% N i ,  19% W sclf ided on . .  
alumina, Harshaw Ni-4303 
E 1/12 
Highest 
Y'i e l  d 
4 
< .002 
< .02 
< "02 
.G2 
Temp, control  very 
d i f f i c u l t  
Stable  temperature 
cannot be main- 
ta incd 
Stable  temperature 
cannot be main- 
ta ined.  
GENERAL AMERICAN RESEARCH DlVlf4lON 
1c 
Laboratory invest igat ion of methanol formation from C02 w i l l  be i n i t i a t e d  I 
I 
I 
1 
during t h e  next quarter.  
l i t e r a t u r e  w i l l  be made from which promising candidates w i l l  be selected f o r  
A l i s t i n g  of ca ta lys t s  and processes found i n  the 
I 
~ t h e  ac tua l  laboratory t e s t ing .  Also, a reac tor  su i tab le  f o r  t h e  invest igat ion I 
I of reactions under pressure as required for t h e  methanol synthesis from COP 
w i l l  be b u i l t  and t e s t ed .  
I 
I 
GENERAL AMERICAN RESEARCH DIVISION 
11 


Research and development study related to synthesis of formaldehyde from CO2 and H2 Quarterly progress report, Nov. 1966 - Jan. 1967

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server