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Патент USA US2408397

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1 land, .as‘sign'or tolmperialphemical
?orsley, Norton?c"ngl'il‘ees,v
’_L_imite_d,a corporation ‘.ofV‘GreatfZBritain if
Application May 8,‘~1944,'-‘Sei'ial‘No. ' ~
~' 153451694; r'l'npGreat BritainfApril 1'29, 1943 a:
: '~
cool,- ‘for example, ;at, a; temperature not above
.i'Iv'hishinventionqrelates‘ to the;,;a_ctivation of
~_ 5_
20."':C:':and preferably near 0?‘ G. -
umtcron-tainillg =;caialysis ~§11iiab1e v for the
If desired direct contact between the metallic
'der to. Sulphur trier-ice.’ 7
iron‘ and the catalystm'aybe avoided for ex
,~ amplev by ‘placing‘thee‘metallic ~ iron: in § a suitable
vesself and " separated‘ \ :froin -.the acatalyst‘ to 1 be
activated by'me'an's ofga' partition through. which
catalyst -,.can occur for {example due-towexpos'ure ‘' liquid can'lpasst for-example, the partitiommay
be'constructed ofii‘gauze; perforatedplate;porous
tolexcessively high‘temperaturesfresulting from
iifregillanoperation of the plantkorf due to poisong 7 ,10 earthenware or refractory material.- ‘It should
be" understood that ‘such materials should be sub-l
'stantially ‘inert under .the conditions of. reactivaj
mg, .‘for‘ example :by‘ compounds -_ of ‘ arsenic. 7 Also
they/initial;v activity of platinumrlcontaining vcate
7 tion.
alysts may be low due to faulty ‘preparationsand
Alternatively, “the /metallic; iron emayi-loev
placed (in a container .throug'hjthe rwallszotfwhich
3 JIIheJ-Epresent inventionfprovides a”;
.‘ i.‘ process 15 liquidican pass; thiscontainer; then being placed
whereby» notkonlyl cane-{deactivated >‘platinuml
containing catalysts be reactivated but by means
in'a-‘vessel containing the catalyst. In bothicases
activity can'bé improve
placed'z‘i‘ndt :and gaseous sulphur dioxide passed
an aqueous solution,v of sulphur; dioxide;v may-then
be.=:;introduced into/the vessel,_ or. waterzpmaywbe
of which the activity‘ of_ eatalystsuprepared by'
,nd having.’ normal tor J poor
.‘According . to the - present’ invention - platinum;
cqniaimnaqatalysis suitable mime-oxidation of
by treatment with ~anzasilieous;solution: obtained
it’ has beenfvfound that even -'b.etter activation
can be obtained; if‘. the-catalyst. is: given \ a pre
sulphur vdioxideto ‘sulphur, trioxide j are activated
byv-theinteraction»oi‘ivsulphur dioxide and-metallic
‘' ?As"a.=further
.of the present invention,
liminary treatment withknitrichcid. ;A dilute
solution, vfor example,v onescontaining 10% by
weight‘of nitrie acid, is‘ satisfactory. The nitric
_ ‘The;3aqueous;_~solution¢-suitablei
in the presence qi?-waterl;
V» ‘use;->_-~,_
acid may‘ be used warms? vThe preliminary treat
iii-sit? therresent mvention may ‘be. brepared
' meat-"may be followed 'byai’washing ‘of the cat
by placing wateruandemetallic iron, for» example;
injthef'form of iron'nailsfin a suitable container
andljrnassing gaseousv sulphur dioxiderintq-the
' alyst ‘with’ water before‘ the treatment‘ with vthe
30 aqueous" solution ‘obtained by the‘ interaction of
sulphur'fdioxide and metallic iron‘ in the presence
of water; Thetreatment'with the v‘aqueous solui
ti'o‘nlobtaine'd by the interaction" of; sulphur di'-'
oxide and metallic iron in the presence of‘ water
, mitiuraz After .csiQpping-ihe‘stream of sulphur
di'QXi?Er-the aqueous Solution; may beii‘decanted
‘ from residual metallic iron before use.;_-_Alter
nativelyxihe -, metallic iron‘may/ be; treated with 35 with or z'withoutvl'al preliminary "‘ltreatment ‘with
nitric ' 'acidy-vmayé be ‘1 repeated , one lorimore times;
an, squeals ‘Solution of sulphur; diexida @During.
We ‘have @found‘the process 'of'this invention
the preparation of‘, thesolutions. it islodesirablle
tokeepivth'em cool, that is at a temperature. not
above “20" 'C. and. preferably in the region of 0"“ vC.
- particularly suitab1e¥~for the treatment of? cat
‘ alystsv containing platinum supporte‘d-vonwsilica
Itn‘order to obtain the maximumv increase in the 40v
activity'of a given 'catalyst,_ theis'olutionrshould ' "
betusedlas soon‘as possible after its preparation,_
and: kept ‘0001 during‘ the reactivation treatment.‘
After treatment with the solution'and separaéy ’
tion [from any residual iron the catalyst is washed
with water and dried by: cautious l-heating.v 1 v 'u
:i Instead .offpreparing'lthe activating. solution
separately andJu‘sing-itas hereinbefore described,
it has beencfound‘preferable topproduce the ;__so1u->
tion; infsitut, Thusrithe metallic ; iron mayabue
mixed-with the catalyst to be activated and the
mixture treated with anaqueous solution con
‘g. ( sulphur 1 dioxide (or. ‘ with‘fgas'eous; sulphur
‘During such
the m1,
I temple ‘2
TE‘S‘A': (lament mante- cbnj'tairimg 6%1193? vol;
umeof ‘sulphur’ dioxide and"94z;%_' by_vo'1_ume;.;of
was passed at arate of .1Q0_,_litres‘ per‘hour
over :43. gins. ofua deactivated silica gjel’~ catalyst
' containing-.QL8% by weight of platinum, the, inlet
gas‘ temperature being maintained ‘at’ 330°; C,
The. conversion of sulphur dioxide to vsulphur
trioxide was found to be 72.71%’.
. , .»
I, I
Compared with this asamplelofrthe same deg
activatedilcatalystz was‘, mixed/with iron‘ nails
and‘ t" aid with Saturated-aqueous Solution c
dioxide, @139. ‘minutes. at mom; ism“
and iron nails with water, removing the iron
washed in running water for 10 minutes, and
nails and drying the catalyst in a porcelain dish,
afterwards dried.
the catalyst was .used exactly as above described
After this treatment the catalyst was tested
when the conversion of sulphur dioxide to sul
phur trioxide was found to be 85%.
Example 2“v
under the same conditions as in Example 4 and
the conversion of sulphur dioxide to sulphur tri
oxidehwas found to be 87%. _ _,
A sample of'rthe same‘:‘deactivated“catalystas"
‘ a
j ‘
3‘ I.'"A process for the'activation of platinum
containing catalysts suitable for the oxidation of
used in Example 1 was digested for 50 minutes
in a cold nitric acid solution containing 10% bywlm sulphur dioxide to sulphur trioxide comprising
weight of nitric acid, washed-with‘ ‘water; mixed;.-H treating; the-catalyst with an aqueous solution
with iron nails and treated with a saturated
prepared by the interaction of sulphur dioxide
aqueous solution of sulphur dioxidekfori 301mm
and metallic‘ ironj in the presence of water.
. 2; A processxforthe activation of platinum
utes at removing
room temperature.
the iron nails
' Afterand
drying‘ as‘
vcontaining catalysts suitable for the oxidation of
above described, the catalystwaseused:under the:
sulphur‘ dioxide‘v to sulphur trioxide comprising
interactingi-sulphur dioxide and metallic iron in
the presence of water, removing residual iron
same conditions as in Example ‘1_',.,_Whenthe;1cone§:1
version of sulphur dioxide to sulphur trioxide was
found to be 88%.
* from the solution and treating the catalyst with
By repeating the treatment used in this exam 20 the solution.
ple, ‘it was found that a- conversion of‘ sulphur
3,1 A process for the activation of‘ platinum
dioxide to sulphur trioxide- of; 92% wasobtained;
contain-ing catalysts ls'uitable f'or‘the- ox'idationof
sulphur dioxide to‘ sulphur‘ trioxide which 'com-'
prises interacting sulphur dioxide and ‘metallic
A dry gaseous mixture containing 6%v by- vol 25 iron' in the presence of water and the‘ catalyst.
ume of‘ sulphur dioxide and. 94% by volume. of
4. vA process for the activaticn‘of platinum-'
air was-passed over: a silica gel catalyst contain
containing catalysts suitable for'the‘ oxidation of‘
ing 0.3% by weight. of‘ ‘platinum at‘ a rate; of‘ 100
sulphur dioxide’ to sulphur triox-ide which com
litres per hour per 36 gmsqthe inlet gas tempera
prisesi'nteracting sulphur dioxide and metallic‘v
ture being maintained‘at 380°‘ C. Theconversion ’ iron‘in the presence of water-=at atemperature
of‘sulphur dioxide to vsulphur trioxide.Was;-;62%_.
not exceeding 20° C.', separating; residual‘ iron
‘After! activation ‘of ‘this: catalyst: as described’ in
from the solution and-treati'ngthe catalyst'with'
Example 1, thesconversion roseto 82%.
Hydro-gen containing a little arsinewas; then
5. 'A process for the activation of platinum‘
containing catalysts suitable for the oxidation of
passed over the catalystwhich.wasrmaintained
at: 4003-02, after which-the? catalyst‘ was used for
sulphur- dioxide to sulphur tri-oxide comprising
treating the catalyst‘at a'temperature notex
the productionxof' sulphur 'trioxide‘ underthesame
conditions asbefore the poisoning with arsenic.
ceeding 20° C. with an aqueous’ps‘olution prepared’
It was then vfound thatthe conversion: had
by the interaction of sulphur‘dioxide and metallic
fallen to 76%. After reactivation under the same 40 iron in the presence of wateri
' "
conditions as in'Example 1, thejcatalystrwasagain
" 6'.- A process for‘ the activation of platinum
used’ forthe conversionsof sulphur'dioxidea to
sulphuritrioxide, as" above described.
The conversion was. found to be 82%‘. ' I
containing‘ catalysts suitable forthe oxidation- of‘
sulphur- dioxide'to sulphur trioxide comprising;
interactinglsulp-hur dioxide and metallic iron in‘
the‘ presence of water and they catalyst at a tem-‘
Example 4f- '
perature not exceeding-20°‘ C.
A drygaseous, mixture containing 6% by vol
' ‘71A process for the activation of platinum
ume ofsulphu-r" dioxide andv 94%v by volume of
air was‘passed' at a rate of‘ 100' litres-per hour over
36 ems; of a“ silica gelv catalyst containing; 0.3%
by'weight of platinum, the'inletgasvtemperature
beingmaintained at: 390° C. The conversion of
sulphur’ dioxide: to sulphur trioxide was found
with an aqueous: solution obtained by interacting
sulphur dioxide and metallic iron‘ in thelpresencel
Afterv treating the catalystv once as described
' After repeating; the treatment twice the» con
version wast87-%‘ under the same operating con:
Example 5
containing-catalysts suitable forthe-ox'idation of’
sulphur dioxide to" sulphur trioxidej comprising
ditionsras before-'the-treatment:was 81 %1.
-8-." A- 'process‘ for ‘the activation ofvv platinum-‘r
' in-Example'2; theconversion under-the sameqconr
,A sample of the same catalyst as that used in
Example 4 was. treated as, follows.‘v ' ,
contairiing‘catalysts suitable for the oxidationof
sulphur d'ls'xlde to" sulphur trlOXlde-comprrsmg}
treating the-catalyst with nitri'cacid, washing the2
catalyst‘ with water, and- treating the catalystE
The‘ catalyst was digested for 30""minutes' in i. ,
cold 10% nitricacid', and then washed in run:
ning water' for 10min'utes.v Meanwhile; sulphur
dioxide was passed "into ice-water" to which iron
treating vthe catalyst with nitric acid, washing‘
with. Water, and;then treating the catalyst with;
aiilaqueoussolution prepared by the interaction
ofvv sulphur dioxide and metalliciron in“ the pres-'
encevv of water’ at: ‘a temperature" noteexceedingl
209 C.
9: 'A; process: for; the-"activation; of platinume
containing vcatalysts suitable > for: the oxidation ' of
sulphur: dioxide to sulphur? trioxide comprising
nails had been added thetemperature-beingmain
treatin'g?tli‘e catalyst with ani’aqueous; solutionv
tained at about 5° C. by means'of ice. The orange _. __
obtainedi by! the interaction off sulphur dioxide:
coloured solutionwas' decanted‘ from the- iron 70
andjrnetalli'c iron in the presence of‘water at-a
nails into another vessel which was cooled'lwith
ice,‘ The catalyst was added,rthepvessel ‘was cov
ered to check oxidation and left tov standhwith,
occasional Shaking for one-.hour.'. Then theucatal-l
temperature in'the region-of0°‘C. -
10.. _A process ‘for; the activation of? platinum
containing‘ catalysts suitable for the oxidation ‘of’
_ sulphur dioxide to sulphur" gtrioxide“ comprising
lystv was separated from the ‘liquid by filtration,‘ is interacting sulphur‘ dioxide and: metallic iron in
the presence of water and the catalyst at‘a tem
perature in the region of 0° C.
11. A process for the activation of platinum
containing catalysts suitable for the oxidation of 5
sulphur dioxide to sulphur trioxide comprising
treating the catalyst with nitric acid, washing
with water and. then treating the catalyst at a
temperature in the region of, 0° C. with an aqueous
solution obtained by the interaction of sulphur
dioxide and metallic iron in the presence of
water at a temperature in the region of 0° C.
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