Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles
In this study a technique for the surface modification of ceramic membranes, consisting of 70 % AI2O3 and 30%  Zr02 by disperse silica and complexes of cobalt with 1.3-diazoles has been developed. This was done by first reacting them with silica and then with γ-aminopropyltriethoxysilan...
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| Datum: | 2001 |
|---|---|
| Hauptverfasser: | , |
| Format: | Artikel |
| Sprache: | Englisch |
| Veröffentlicht: |
Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine
2001
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| Online Zugang: | https://surfacezbir.com.ua/index.php/surface/article/view/50 |
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| Назва журналу: | Surface |
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Institution
Surface| _version_ | 1869291134884249600 |
|---|---|
| author | Belyakova, L. A. Linkov, V. M. |
| author_facet | Belyakova, L. A. Linkov, V. M. |
| author_institution_txt_mv | [
{
"author": "L. A. Belyakova",
"institution": "Інститут хімії поверхні НАН України"
},
{
"author": "V. M. Linkov",
"institution": "University of the Western Cape"
}
] |
| author_sort | Belyakova, L. A. |
| baseUrl_str | |
| collection | OJS |
| datestamp_date | 2018-11-27T09:42:39Z |
| description | In this study a technique for the surface modification of ceramic membranes, consisting of 70 % AI2O3 and 30%  Zr02 by disperse silica and complexes of cobalt with 1.3-diazoles has been developed. This was done by first reacting them with silica and then with γ-aminopropyltriethoxysilane, cyanuric chloride (or 1,10-diiododecane) and 1.3-diazole (imidazole or histamine). Heterogenized cobalt complexes with 1,3-diazoles, grafted onto the membrane surfaces, were obtained. It was established that the cobalt complexes with 1,3-diazoles had a deformed tetrahedral structure and it was only the nitrogen atoms of the grafted heterocycles of imidazole which were involved in the formation of four co-ordinate metal complexes. The catalytic activity of the produced membranes in the reaction of the liquid phase oxidation of cumene by molecular oxygen under mild conditions (atmospheric pressure and a temperature less than 100 °C) has been demonstrated. A study of the oxidation mechanism revealed that the reaction proceeds via the formation of oxygenated complexes of 1,3-diazoles with cobalt ions on the catalytic membrane surface. The formation of radicals takes place due to the oxygenation of heterogenized cobalt complexes, according to the following reaction: O2∙Co(II) → O2 -Co(III). The catalytic reaction of cumene oxidation proceeds with the participation of Co(III)-catalysts according to a mechanism involving electron transfer. The newly developed method for the preparation of catalytic membranes can also be used for the manufacturing of selective ceramic membranes with hydrophobic or hydrophilic surfaces. |
| first_indexed | 2025-09-24T17:44:38Z |
| format | Article |
| fulltext |
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DIRЕCTIONAL Il{oDIFYn{G oF INIORGANIIC oхIDЕs
SURFACЕ BY CAТALYTIС ACTIVЕ CoMPLЕхЕs oF
СOBALT WITI{ |'3-DIАZoLЕs
L.A. Bеlyakovа l аnd V.М. Linkоv 2
llttstitutе
of Suфсе Сhеmisrry, Nаtioпаl Асаdеmу of Scienсеs
Gеn. Nаumov str. I7, Kуiv-I64, 03б80 UKRАINЕ, e-mаii,. i-ьеt@mаil,kаr'nеt
2 Dеpаrtmеnt of Сhemistry, Univеrsitу of thе Wеstеrп Саpе
Bellуillе 75 35, Rеpubliс of SОUTI{ АFR]CА
Abstraсt
In this studу a tесhniquе for the suгГaсe modifiсation of сеramiс mеmbгanеs,
сonsisting of 7ОYo AlЮз and З0oА Zroz by dispеrse siliсa and сompleхеs of сobalt w,ith
l,3.diazolеs has bееn devеlopеd. This was done by first геaсting thеm with siliсa and thеnwith y.aminopгopyltriethorysilanе' сyanuriс сhloride (oг 1, 10-diiododесanе) апd
1,3-diazolе (imidazolе oг histamine). Hеteгogenizеd сobalt сo'pi.*", йth 1,3.diazolеs,
graftеd onto thе mеmbranе surfaсes, werе obtainеd. It was еsiablishеd that thе сobalt
сomplехеs with l,3.diazoles had a dеfoгmеd tеtrahеdral structuге and it was onJy thе
nitrogеn atoms of the graftеd hetеroсусles of imidazolе whiсh wеге involvеd in thе
formation of fouг сo.oтdinatе mеtal сomplехеs. Thе сatalyic aсtivitу of thе produсеd
mеmbгanеs in thе rеасtion of thе liquid phase oхidation of сumеnе by molесulaг oХуgеn
цndег mild сonditions (atmosphегiс pгеssuге and a tempeгatuге lеss than 10O .С) has Ьiеn
dеmonstrated. A study of thе oхidation mесhanism гevealed that thе геaсtion pгoсееds via
thе foгmation of orygеnatеd сomplеxеs of 1'3-diazolеs with сobalt ions on ihе сatalr,tiс
mеmbгanе suгfaсe. The foгmation of гadiсals takes plaсе duе to thе oxygеnation of
hеterogеnizеd сobalt сompleхеs, aссording to thе following гeaоtion: oz . Co(II) -+ oz
Co(III)' The сatalрiс гeaсtion of сumеnе oхidation pгoсeеds with the paгtiсфation of
Co(Iil).сatalysts aссording to a mесhanism involving еlесtгon tгansfеr. Тhe nеwly
dеvelopеd method foг the pгepaгation of оatalуtiс mеmbгanеs сan also bе usеd foг the
manufaсturing of sеlесtivе сeгamiс mеmbгanes йth hydrophobiс oг hydrophiliс suгfaсеs.
The рresent studу dеals with the pгеparation of сatalуtiс, сеramiс-basеd
mеmbranеs, usеful foг thе oxidation of organic substanсеs. Theге is a sегious nееd
nowadays to соnduсt suсh pгoсessеs undег mild сonditions, as undег suсh сonditions it is
possible to synthеsizе many impoгtant organiс substancеs' It сan bе ехрeсtеd that a highlу
еffeсtivе сatalуtiс mеmbranе сould bе dеvеlopеd if a сatalyst, whiсh is aсtivе in oхrdaiion
undеr mild сonditions, was to bе intгoduсеd into thе сeram,iс mеmbranе matriх. Aссuгatе
sеlесtion of thе сatalцiс phase and thе appropгiatе сегamiс mеmbranе suppoгt wеге pге-
rеquisitеs for thе pгеparation of suсh сatalуtiс mеmbranеs.
It is known from thе litегaturе [1] that siliсa сan bе usеd fог thе preparation of
mеmbгanеs as it is possible tо obtain stablе sоIs and gеls from it [2]. It is also the main
сomponent of industгially pгoduсed poгous glass mеmbrаnеs Il,3]' Тhе suгfaсе сhеmistry
of siliсa has beеn bеttеr-studiеd [4-6] than that of otheг oхidеs of multivalеnt mеtаls whiсil
aге usеd in pгoduсtion of сегamiс mеmbranеs, foг еxample, zirсonium-' titanium- and
сеrium oхidеs. The pгopепies of siliсa сan bе drastiсally сhangеd by grafting with diffеrеnt
organiо, siliсon oгganiс oгсo-ordinatе сompоunds [6-9] If siliсa is pгеseniin thе сегamiс
mеmbгanе matгix then its сhemiсal modifiсatiоn сan rеsult in сhangеs in thе propeпiеs of
9l
thеinorgarriсmеmbгanеs.Forеxamplе,thеrесouldbеaninсrеasеinmеmbranеthегmal
and сhэmiсal stabilitу, t-ь. ..l11ь,u,,'".,u.ъ." .oйb" пlud" hydтophobiс and thеrе сould
bе сontrollеd сhangе in thе poгe sizеs "г
it'.
-.Ъ*branеs.
Сhеmiсal modifiсation of
mеmbгanе suгГaсеs aiso pгovides a waу m йь....ial1tiсa11y aсtivе mеmbranеs сan bе
pгеparеd.
Сomplеxеsotl,3-diazoiеs-withtгansitionmеtalsarеaсtiveinthеoхidatioп,
rеduсtion, dеhydгatron una ьус,o*уtution ,.u.iions oforganiс соmp.ounds [10]. Thеrеforе,
thе соrtvеrsion of 1,э.a,a,oiе, into hеterog.;;;;; сatall,tic forms is of intеrеst from two
роints of ui.*, nu,,'"i;:ъ;-*.;'ntь.sьЪг,]i;;;* and сatalytiс phasеs and for thе
modеling of aсttvе,-J, "iЬi"".йyu.
t11,12]_ii;.: i:::*'::-j'hat
inorganiс mеmbranes
that rvеrе modifiеd *й "".pь*..
oг transition mеtals with l,3-diazoiеs would bе
саtаi1tiс aсtivе fOг th;;;id;Ыof organiс compounds undеr mild.сonditions.
Тhе аim оf thе pгеsеnt studу *u, .o-ini",tigatе the possiЫlitу of prеpaгing novel
iпоrgaпiс ,n.n',b,unе,= lhat would сombinе tь" й""ьaniсal and сЪеmiсal bеnefits of
сегairrils пratегia}s. ;"';щ;;i; uа,o,.ptlon |,Ьp.пi"' of siliсa.and thе high сatalytiс
з;tivitу of соmplехe,.oгi,in,ition mеtals ;H.;,ъ-;;;olеs. ,Suсh
mеmbгanes would be
usеful in solving ,.u.,J i*po,tu", p,oьr.*,.,.tй 'иiь
сatalytiс сonvегsion of a variety
оГ organiо ,uь,,un,.Т. iйi."l p,oьt"*,
.i;;й" .сatalуtiо
dесomposition of toxic
: Ы
;i: : ;нт hтlтж:."xff''"Т:i
j#'}"Н,
Tу.:,, ",
oхy gеn *
T.
.,,
:
q
.to
d е m o n st r at е t ь е с at й i с. p r o p егti е s
.o
f
:lr: JiТ" i}ж:*жжт,ffi:* :'"ili :ТТ;
,*." p,"pu'"о bу' the impгegnation
".*,:]ll.".*i.h imidazolе or histaminе.
fu ;.;Hs':;:}:;I:hЪ"кжТi.'il1}J;H:[iф'*:*у'-::ъ]..#;ЧЧ:"
and 30 oА ztгсada,tuьirii.а with yttгia, ;;;;;ifi. suгГaсе arеa was bеtwеen 2 and
5m?/g,thеavегagе.diamеtеrofthеporеs,".'ojрmandth^еtotalDorositуwas457o.
T o еn s ц r е, # ЁH ; ;: * Ф:: l# -*
ъ, l,ш:?T " Ti' уТ"t.'ili"li
ffh,T"Т;?;l?fiй:Щ*: ;ii*}ffi ]i,.' l.i" j''.-.i",''' o.diiododесan"] uno
i, з сi й i. t'#*,:
:H' :i::'T: ж l'', o *
1 1 *"^ч, :n; "11fТ;'#il:lТ
x1ъ:: "
геsuit of сontaсt ot.thеЬodifiеd mеmbгan.,,]pp"*. *rth 0 0l.0.03 М solutions of CoClz
in acеtonе for 3 h at25'С, -lеd сobalt сomplеxеs йth
ь,p
"".,
o,.o pL'ш ау :f 'h.,.':"},ъ i:$'ъ':r.]:':;iffi ;; ;; 1гi. в в o o гy.
Li,*r:л-ffiТТ.;Ж1"'J.'H'ilii:а"""г#'ьjl;йъ;;thеstandшdattaсhment
;; ;ЫЫЫй;}:: rffi|j! ff iЁ;".l'.'t сomplеxе s with, 1, 3. di azolеs werе studiеd
loг thеir сatalуtiс ..il"i,y in thе liquid p;;;;;;;;tion of оumеnе. Thе сatalytiс aсtivitу
was dеtеrminеd from the ratе ot o*yg.n ;i;";;й; ;ч'ing thе. rеaсtion, using volumetriс
equiрmеnt' Тh. ;;;;;ц.Ъi ь, ЬЪ,i"g ".i.Ь;iс
aсtivitусomprised a^glass rеa111йth
a сatalуst-сonтalning ampoulе, u p,.,,u,Jрu*i .:o . Yj::T^:i
vеnts for еvaсuation and
oхvgеn supplv #:;'r;;;';,:".ы.Jй a-piatform that сolld bе agitatеd. orygеn at
atmosphегiс o,";;J;;, u,.o as thе ;tdй A сonstant rеaсtion tеmpеraturе was
maintainеdbуusingathегmostat^;^А out undеr thе ех-kinеtiс сondition with thе сell
Тhе ехpегimеnts \,\'еrе сaгnеo..'
shaking г,.qu"n.i,.)...oi"g !oo o.,"irru"tio";;;;',: Pd o^:Т'n. tеmpеraturе rangе 60-
90 "с Undеr йЦ ffii';l.*: #ТlJij:}::ж,1.,ж ;i:ТЦ":":J?Тll:
*ж:,т;::1 H: ffi:Jж ;11ж: fi:,.'#;;;;"-;йi; .; ignorе thе infl uеncе of thе
,еa.tion pгodr-.сts оn thе reaсtion ratе'
92
I
)
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a
е
l
)у
xd
ia
al
\.12
liеd
vity
)tпc
д/ith
and
nat
was
сеil
60-
rting
г the
f thе
atY. .I
ё{,гэ
NN*rl
a\
si
НNt
Lсq
"! \-t-t
NN>,/
?
si
/gz
г| ..2'\
-t' f|
-zСI1
zс6 l-|
NN
ч (
,,, si,
L:Сo(II)=l 1
дн
н9t.^--
.сH
l-lNN\t
(
si,
Г:l
NNYsi,,
|:I
NN\,
(
.q
l:I
NN\,
I
Sr
t-t
NN
ё/
si
г1
NN
l*
tes
bу
nd
,'ith
)r rр
,еnt
9l "'
LO LO
нN
'.т al
Y^ ar
Lо
2
'91 "'.LO
А.ll сobalt сomplеxеs with 1,З-diazolеs gгaftеd onto thе suгГaсеs of modifiеd
mеmbranеs possеssеd сatalytiс aсtivity in thе liquid-phasе oxidation of сumеnе. Тhе
hеtеrogеnizеd Co-сomplехеs havе a high сhemiсal stability. Thеу did not disintеgratе
upon hеating up to 200.250 oс Thе stгucturе of thе graftеd оobalt сomplехеs did not
сhangе upon сontaсt йth сonсепtгated aсеtiс aсid and diffегеnt solvеnts suсh as aсetonе'
toluеnе and watег, foг 120 h at 25 .С'
Thе mеmbгanеs modifiеd by hеtеrogеnizеd сobalt сomplехеs with 1,3-diazсllеs
геvегsibly adsorbеd molесular oxygеn (the band of сhaгgе transfеr tigand-mеtаi
п*oz _) о*Co fтom oхygen molесulе to thе сentral ion of Co-сomplех with the maхimum
at25510 сm-l tl2,lз]). It was eхpесtеd theгеfoге that sцсh mеmbгanеs would havе high
сatalу'tiс oxidation aсtivity towards oгganiс сompounds. Fouг сo-oгdinatе сomplехеs оf
сobalt on the suгfaсеs of the mеmbгanеs modifiеd by imidazolе (oг histaminе) aге idеntiсal
and havе a defoгmed tеtгahеdral structurе [14]. It is onlу thе nitгоgеn atoms of thе graftеd
hеtеroсyсles of imidazole that aге involved in thе foгmation of metal сomplехеs' Тhе
struсturе of thеsе сomplехes is pгesеntеd bеlow'
L:Co(ll)=2 1
2
z
,дtllua"z'\cH
t-t
NN\1
St
Тhе deviations from thе ratio L : Co(II) = 2..I and 1:1 (Тablе l) are сaused by thе
simultanеous foгmation of both туpes of сomplехes.
Thе сhеmiсal struсtuгеs of thе obtainеd hеtегogеnizеd mеtal сomplеxеs of l.З.
diazoles with сobalt rеsеmblе the struсtuгe of aсtivе сеntегs of mеtal pгotеins' Thе study
of thе oхidation of organiс substanсеs undеr mild сonditions, using suсh biocatalyst-
mimiсking сеramiс-basеd mеmbranes, was of sресial inteгеst.
All thе modified membгanеs (aftеr modifiсatiоn by thе сoba1t оomplеxеs with i,3-
diazоles) possessеd сatalytiс activity in the rеaсtion of thе liquid.phasе oхidation of
сumеnе at tempеratures bеlow 100 "C. Тhеiг struсtuгes геmained rinсhangеd upon сontaсt
with сumеnе and thе oхidation pгoduсts suсh as сumеnе hydгopегoхidе, aсеtophenonе and
dimethуlphеnуlоarbinol. Тhе геaсtion гatе dесгeasеd with timе (Fig. l), but thе
гegеneгation of thе сatalyst was possiblе' At lеast siх subsеquеnt геaсtion-геgеnегatioп
сyсles wеге pегformеd and a i00 7o rеstoгation of сatalytiс aсtivitу rvas obsегvеd in еaоh
сase. Thе rеgeneration was aсhiеvеd by passing argon at l50"с and o)rygеn at room
tеmperatuге through thе геaсtoг,
93
Tablе l. Surfaсе сontеnt of ligands a1d сo|ar1ions in сataiytiс mеmbranes.
Меtal adsoгp;"";;; ь.ь3 М solution (* - from 0.0l М solution)
Graftеd ligand SuгГaсе сontent oI Co(Il)
(цmol/m2)
Ratio
L:Сo(II)
L ligand
lmrdazolе 2.9
2.5
2.s
.А
2.0
1.2
to
1.5
r ,1 *l.a
i5
l5
L*
1t
2.1
1о
1at.L
1.8
1.6
l.l
1.0
1.0
Histaminе |о
0.6
1^*
l 'т
i.о
n1
1Al.a
1.0
0.9
[t was found that tlre сatalyiс T.'э*ч:
W , mm
3, mln obtalnеj;;;; й'egnation of сobalt сhloride
]..'- ' r т--\ l"io non.rnodifiеd сеramrс .':.bч"'..*lj"-т:
] ;:::#-.;;;-i"*ег .сa1alytiс
aсtivitу in thе
\ ,.u.,,Jn"'o,.;.;; oxidаtioп ""d,.l]: *"^':::::.\.- 1 'jffi*т;l':*u:.lT'.iii:f'"Jl"#"Тi\']-=-.- ] in гie. ),'*.""d'й.a 'h: .,|."1^'::l,1":. ,;:
Vf "*
= (W 2 сu,. /Sior * W2 сo.i*id-ol")
l2
whеrе W сu]
. /sio2 . thе ratе of сumеnе oxidation in the prеsеnсе of Cu-siiiсa gеl; W сo.
iпrrdаzolе - thе гatе
"f
.й;;;;йuiion in,ь. p,.й.. oгuЪoьut' сomplеx with imidazolе.
t_.--i--.
'
''l.,.,#'*аёo-Ыpr.хеs in thе rеaсtion of thе
-.-t{ i riquid-p}HfrжT:ij:::ffiT"tion was aвгliеd-\.
1 ж.,:.^:P::trjl".\:l};'нtr'J-,,!l"'iъ_----ы-----;-_-+';;;;";-*pported сomplеxе.s of
.
сobalt.-with
т ' m,. 'ili"i. t"l'ri'o.i..l i'-:ly:.i:'Ч:?Т:::Iт'mшllon.*"ьЬ-J.*u.u'"а.u,сo-initiatoг.Itisknown
Fis. 1. Thе ratе of сumеnе th"t с";ii".;Ъ.iь-i"*l""d
jn сumеne oхidation
oйation at 65 "C in thе presenсе onrу u.'.ь. ,iй. oi.ьul" ъrmation in thе гadiсal-
of сatalyiс membгanes: сhain o."..*'"-ri'l . ,Еxp.erimеntallу
obtainеd
i - lmidazole . сo (lti= t в; (w-*J;;;;"uiсutat.d 1W.'L."*) сumulative ratеs
; -;;,;";. с" iri! =Ь.Ы ffi:H*fj:;" }#:,:ffi:й ::"jll
imidazole and Cu.siliсa gel aте givеn iпiabr.J.- iьЪ.'otal ratе of сumеnе oхidation was
.ui"utut.d from thе foгmula
9"1
"2
rc
6оoс
т' mtn
сhain mесhanism. The involvеmеnt of thе
Fig. 2. Тhе kinеtiсs of oхygen сatalyst was limitеd to thе fiгst stagе оf гadiсal
absoгption duгing сumеnе oxidation in Гormation oniy.
The depеndеnсe oГ thе rеaсtion ratе ort
the mass oГ imidazolе-сontaining сatalrtiс
mеmbranеs pгеsеnt in thе rеaсtor (q) is given ;.,
Fig 3. Thе rеaсtion гatе initially iniгеaйd w.;ri
an inсгеasе in the amount of thе сatalуst ariсl
thеn rеaсhеd a constant valuе' Ifplottеd in сo'
oгdinatеs w = f(q'o) thеn thе геlationship rvаs
linеaг. Similar rеsults wеге obtainеd ц jth
histaminе.сontaining сatalytiс mеmbгat;сg'
Basеd on thе abovе mentionеd findings it ъ;ils
сonсluded that thе pгoсess of сumеnе oхiсlatiоn
in thе pгеsenсе of сobalt соmplехеs wittr 1,З-
diаzolеs graftеd on the suгfaсе of modifiеd
mеmbгanеs took plaсе aссoгding to a гadiсal.
s
s
d
n
n
rf
thе prеsеnсе of thе сatalуtiс membгanе
at 60.80 "с (l0 mg сatalyst,
Flistamine : Co(II) = g 9;
The intгoduсtion of сaгbon with а pге-
oxidizеd surГaсe as an inhibitoг of thе гajiсat
foгmation pгoсеss lеad to a dесгеasе in thе
сumеnе oхidation ratе (Fig 4) and tеstifiеd tc
thе paгtiсipatiоn of thе гadiсals in thе геaсtiоn
mесhanism. Thе appеaгanсе of thеsе radiсals is еithег duе to thе dесomposition of сЦmеnе
hydгopегoxidе oг to thе aсtivation oГ molесulаг oxуgеn. As сan bе sееn frоm Fig 5'
геplaсement of oxygеn with aiг did not affесt the kinеtiсs of сumеnе oxidation in thе
pгеsenсе of Cu-siliсa gеl. It was assumеd thеrеfоrе that in this сasе thе гadiсals rvеrе
foгmеd duе to thе hуdгopегoхidе dесomposition' A similaг геplaсеmеnt in thе сase оf
сatalytiс membranеs modifiеd by Co-сomplеxеs with 1,3-diazolеЪ геsultеd in a signifiсant
deсrеasе in thе сumеnе oxidation гatе, whiсh was сomplеtеlу rеstoгеd whеn puгJoхygеn
was used again. Thеse rеsults testi8/ to the еxistеnсе of two diffеrent rеaсtion mесhaniйs
that play a rolе in thе pгеsеnсе of thе Сu-siliсa gеI сatalуst and сatalyiс mеmЬгanеs
сontaining Co-сompleхes with l,3-diazolеs. Appaгеntly, thе ability of Co-сomplехеs tо
foгm oxygеnatеd intегmеdiates plays a majoг rolе in thе latteг сasе.
ТabIе 2. Ratеs of сumеnе oхidation (еxpегimеntally obtainеd W*o "* and сalсulatеd
Wo,..* ) at simultanеous pгеsenсе of Cu-iiliсa gеl and ..*Ь. mеmbгanе
modifiеd bу Co.сomplех with imidazolе (ratio Imidazolе : Cо(iI) = i 61
:d
1е
of
th
Dу
vn
0n
al-
еd
les
;hе
ith
r'8S
Amount of сatalvst o w"*P .u, 1o \l/.аlсYY сum 10
) moУl .s
moИ s
5.0
10.0
20.0
1.5
l-у
2.2
t.4
1.8
20
Co-
эlе.
Тhis assumption was соnfirmеd by a study of the kinеtiсs of oхygеn absoгption bу
dеoхygenatеd Co-сomplеxеs (Fig 6) Thе dеoхygеnation Was сaгriеd out bv hеatins thЬ
сatalyst and the substratе in aгgon (сuгvе 2) and oХуgеn (сuгvе 3) up to theЪoiling Боint
of сumenе (152-15з "C). A reduсtion in thе сumеnе oхidation ratе was obsегvеd й.ьotь
эases. In an attempt to ехplain thе abovе mentionеd phenomenon it was suggеstеd that
the oхygеn aсtivation еquilibrium oz . Co(II) ё oz-' Co(III) whiсh prеvailеd on the
;аtalytiс mеmbгanе surfaсes was no longеr pгеsent at elevatеd tеmpегatuгes duе to
o<
1l
I
.-l /'''ii /
it 1)lr
\\'^ rl-l!l - lllln
с. !ng,l
q
Fig' 3, Thе гatе of сumеnе oхidation at
diffеrent rеlativе сonсеntгations of the
;';;".;.talуst (б0 oC' ratio Imidazolе .
Ё;i';;-i;ii ""а
1.0 - сuгvеs 1 and 2
геsресti\'еlу)
Fig. 4. Еffeсt of сaгbon with oхidizеd
'""й..
on thе kinеtiсs of oхygen
ab,o,ption Voz during сumеnr
;;;il; in the prеsеnсе of сatalytiс
i,"'Ъ'*"' with a ratio llistaminе :
ё"i'il = 0.9 (60 oC, 10 mg сatalyst). l
]'itiou' aoсing oxidizеd сшbon; 2-4
- ;''h ;h. addйon of 20, З5. and 50
mg of oxidizеd сarbon rеspесtlvеly
t' min
Fig.6. Тhе еffeсt of dеoхуgenation.on
;;:. ;i".ii.; of oxуgеn absoгption Voz
Ju,ing .u..nе oxidation in thе. prеsеn9е
ii.iьZ
"u,urу*iс
mеmbranе with a rauo
Ёi'i.'i". ' сo$r) = 0.9: without
i."l'*.*''"n (i), dеoxуgenation in
;;;;" atmosphere (2) and o)rygеn
atйosphеге (3)
1
I
I
l
l
i
эsgсr
Fig. 5. Kinеti., ";.;;."
absorрtion Voz
iu?,n* .u..nе oхidatiоn in thе prеsеnсе
;;,'ё"".;t.; 9.' !]J: ;l|JT. :Ё:'1l;
mепlbгanе rvith a гatto п
=09
0
гemoval of oxygеn from thе surfaсе of thе сatalyst. Restoration of thе сatalytic propеrties
took plaсе wйй tt,е еquilibrium was rеstorеd and an adеquate quantity of Co(III) was
p,.,.nt. Appaгеntly, thе initial foгmation of сation-radiсals on the Co(Ill).mеmbrane
сatalyst, i..analogous to thе proсеss of oxidation of alkylaromatiс сompounds in thе
рrеsеnсе of homogеnous Co(III).сatalуsts Il6]:
Arсн(снз) z + Co(IID -t [ArCн(Cн3)сн3]
-. + Co(II).
Thе loss of a proton takes plaсе as follоws:
[ArCH(СHз)6HзJ- .+ ArCH(CH3)CHz.+ FI*. .
ln thе prеsеnсе of oхygеn thе following rеaсtion takеs plaсе.
fuсH(сFrз)сHz. + oz -+ fuCH(CНз)CHz.oz. -+ produсts.
Тhе сatalyst is геgеneratеd by mеans of the following rеaсtions:
AfсH(снз)сHz.oz.+Сo(II)+ArСH(СHз)сFIO+Co(III)+oH-
Afс}I(снз)сHzozН + Co(iI) э AICH(CH3)CH2O. + Co(III) + o}Г
Thе oхidation proсеss did not proсeеd aссoгding to the convеntional mесhanism
'
r ia the dесomposition of сumеnе hydгoperoxidе) but by way of the primary oxidation оt
Сo(II) to сo(lit) bу molесular oхуgen, followеd by thе partiсipation of Co(III) in thе
iгmation of thе сation-radiсals,
Rеferеnсеs
. Bгavе R,R. lnoгganiс Мembгanеs: Synthеsis, Chaгaсteгistiсs, and Applications. Nеw
Yoгk:Van Nostгand Rеinhold' 199l. 750 p.
] Ilег R.K. Thе Сhemistry of Siliсa: Solubilitу, Polуmеrization, Colloid and Suгfaсе
Propегties and Bioсhеmistry of Siliсa. New Yoгk: John Wilеy and Sons, l 979. l008 p.
-. Sсhnabel R., Vaulont W High-prеssuгe Tеchniquеs йth Poгous Glass Меmbгanеs //
Desalination. - 1978. -V' 24,N 1' - P 249-272'
: Linsen B.G. Phуsiсal and Chеmiсal Aspeсts of Adsorbеnts and Catalysts. London-New
York: Aсadеmiс Prеss, 1970. 580 p
j Kisеlеv A.V. and Lуgin V.I Infraгеd Spесtгa of Suгfaсе Compounds (in Russian).
Мosсow: Nauka, |912.459 p
: Vansant Е.F., Van Dеr Vooгt P', Vranсkеn K.C. Charaсtегizаtion and Chemiсal
Мodifiсation of the Siliсa Suгfaсе. Amstеrdam: Еlseйer, l995. 555 p.
. Ungеr K'K. Poгous Siliсa, Its Propегtiеs and Use as Suppoгt in Column Liquid
ChЬmatographу. Amstеrdam: Еlsеvier, 1979' 350 p.
: Chuiko A A.' Gorlov Yu'I' Chеmistry of Siliсa Suгfaсe (in Russian)' Kiev: Naukova
Dumka, 1992.248 P
] Тeпykh V.A., вelуakova L.A. Chеmiсal Reaсtions with Paгtiсipation of Siliсa Suгfaсе
(in lЬssian). Kiev: Naukova Dumka, |991. 264 p.
' ) Еnikolopyan N.s. Poгphyrins; Spесtгosсopy, Еleсtrochеmistry, Application (in
Russian). Mosсow:Nauka, 1987. 384 p.
BurwеllR.L. Мodifiеd Siliсa Gеls as Adsorbеnts and Catalуsts // J. Chem. Technol. -
Ig74, - v. 4' N 6' _P'з70-з,7.|
97
l2.PгеparationandlnvestigationofCobа]tCompleхеsGraftеd.toSuгfaсеofAеrosil/
T.N.Yakubo"i"h,,;;.i";;;;йi", K B";ilй;ii].-v-.i.вono'u,, L.I.Soloрb,
A.A.Chuiko // Adsorptioi*d-}d:oч*';(i;R;;'вn;.
_tяв+- rt rz. . P 55-60'
13. Lеvег A.B'P., с,uy нв. Еlесtroniс i;;;";;.i'"i' Dioхуgеn Complexеs /i
Aссounts Chеm. ""]
..iqiв -v 11,N
9 P 348-355
14'LеverAB'P'ino,g-uni"Еl..',on'"sp..t,o,.opу'й'11'а.""'.Еlsеviеr,1984,420p.
15' Еvmеnenko N.P., ъ;;;i;;;skii Ya B ,'i;;p,atov-v г rnvеstigation of Kinеtiсs and
Меоhaшsm "г
с"i.".^сi-iJation ll p.t,oЬ;й Chеmistry (iriRussian) - 1970. _
,, Н:;,T З i;'|,[#"ju, т,un,ition.Меtal Catalysis London-Nеw York: Chapman
and Hall, 1981' 285 P'
98
|
| id | oai:ojs.pkp.sfu.ca:article-50 |
| institution | Surface |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2025-09-24T17:44:38Z |
| publishDate | 2001 |
| publisher | Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine |
| record_format | ojs |
| resource_txt_mv | surfacezbircomua/bd/be71c889c29338f3281f9778435f6dbd.pdf |
| spelling | oai:ojs.pkp.sfu.ca:article-502018-11-27T09:42:39Z Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles Belyakova, L. A. Linkov, V. M. In this study a technique for the surface modification of ceramic membranes, consisting of 70 % AI2O3 and 30% &nbsp;Zr02 by disperse silica and complexes of cobalt with 1.3-diazoles has been developed. This was done by first reacting them with silica and then with γ-aminopropyltriethoxysilane, cyanuric chloride (or 1,10-diiododecane) and 1.3-diazole (imidazole or histamine). Heterogenized cobalt complexes with 1,3-diazoles, grafted onto the membrane surfaces, were obtained. It was established that the cobalt complexes with 1,3-diazoles had a deformed tetrahedral structure and it was only the nitrogen atoms of the grafted heterocycles of imidazole which were involved in the formation of four co-ordinate metal complexes. The catalytic activity of the produced membranes in the reaction of the liquid phase oxidation of cumene by molecular oxygen under mild conditions (atmospheric pressure and a temperature less than 100 °C) has been demonstrated. A study of the oxidation mechanism revealed that the reaction proceeds via the formation of oxygenated complexes of 1,3-diazoles with cobalt ions on the catalytic membrane surface. The formation of radicals takes place due to the oxygenation of heterogenized cobalt complexes, according to the following reaction: O2∙Co(II) → O2 -Co(III). The catalytic reaction of cumene oxidation proceeds with the participation of Co(III)-catalysts according to a mechanism involving electron transfer. The newly developed method for the preparation of catalytic membranes can also be used for the manufacturing of selective ceramic membranes with hydrophobic or hydrophilic surfaces. In this study a technique for the surface modification of ceramic membranes, consisting of 70 % AI2O3 and 30% &nbsp;Zr02 by disperse silica and complexes of cobalt with 1.3-diazoles has been developed. This was done by first reacting them with silica and then with γ-aminopropyltriethoxysilane, cyanuric chloride (or 1,10-diiododecane) and 1.3-diazole (imidazole or histamine). Heterogenized cobalt complexes with 1,3-diazoles, grafted onto the membrane surfaces, were obtained. It was established that the cobalt complexes with 1,3-diazoles had a deformed tetrahedral structure and it was only the nitrogen atoms of the grafted heterocycles of imidazole which were involved in the formation of four co-ordinate metal complexes. The catalytic activity of the produced membranes in the reaction of the liquid phase oxidation of cumene by molecular oxygen under mild conditions (atmospheric pressure and a temperature less than 100 °C) has been demonstrated. A study of the oxidation mechanism revealed that the reaction proceeds via the formation of oxygenated complexes of 1,3-diazoles with cobalt ions on the catalytic membrane surface. The formation of radicals takes place due to the oxygenation of heterogenized cobalt complexes, according to the following reaction: O2∙Co(II) → O2 -Co(III). The catalytic reaction of cumene oxidation proceeds with the participation of Co(III)-catalysts according to a mechanism involving electron transfer. The newly developed method for the preparation of catalytic membranes can also be used for the manufacturing of selective ceramic membranes with hydrophobic or hydrophilic surfaces. In this study a technique for the surface modification of ceramic membranes, consisting of 70 % AI2O3 and 30% &nbsp;Zr02 by disperse silica and complexes of cobalt with 1.3-diazoles has been developed. This was done by first reacting them with silica and then with γ-aminopropyltriethoxysilane, cyanuric chloride (or 1,10-diiododecane) and 1.3-diazole (imidazole or histamine). Heterogenized cobalt complexes with 1,3-diazoles, grafted onto the membrane surfaces, were obtained. It was established that the cobalt complexes with 1,3-diazoles had a deformed tetrahedral structure and it was only the nitrogen atoms of the grafted heterocycles of imidazole which were involved in the formation of four co-ordinate metal complexes. The catalytic activity of the produced membranes in the reaction of the liquid phase oxidation of cumene by molecular oxygen under mild conditions (atmospheric pressure and a temperature less than 100 °C) has been demonstrated. A study of the oxidation mechanism revealed that the reaction proceeds via the formation of oxygenated complexes of 1,3-diazoles with cobalt ions on the catalytic membrane surface. The formation of radicals takes place due to the oxygenation of heterogenized cobalt complexes, according to the following reaction: O2∙Co(II) → O2 -Co(III). The catalytic reaction of cumene oxidation proceeds with the participation of Co(III)-catalysts according to a mechanism involving electron transfer. The newly developed method for the preparation of catalytic membranes can also be used for the manufacturing of selective ceramic membranes with hydrophobic or hydrophilic surfaces. Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2001-06-10 Article Article application/pdf https://surfacezbir.com.ua/index.php/surface/article/view/50 Surface; No. 4-6 (2001): Chemistry, Physics and Technology of Surface; 91-98 Поверхность; № 4-6 (2001): Химия, физика и технология поверхности; 91-98 Поверхня; № 4-6 (2001): Хімія, фізика та технологія поверхні; 91-98 3154-8091 3154-8083 en https://surfacezbir.com.ua/index.php/surface/article/view/50/49 Авторське право (c) 2001 L.A. Belyakova and V.M. Linkov |
| spellingShingle | Belyakova, L. A. Linkov, V. M. Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles |
| title | Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles |
| title_alt | Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles |
| title_full | Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles |
| title_fullStr | Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles |
| title_full_unstemmed | Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles |
| title_short | Directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles |
| title_sort | directional modifying of inorganic oxides surface by catalytic active complexes of cobalt with 1,3-diazoles |
| url | https://surfacezbir.com.ua/index.php/surface/article/view/50 |
| work_keys_str_mv | AT belyakovala directionalmodifyingofinorganicoxidessurfacebycatalyticactivecomplexesofcobaltwith13diazoles AT linkovvm directionalmodifyingofinorganicoxidessurfacebycatalyticactivecomplexesofcobaltwith13diazoles |