Title of Invention	A PROCESS OF PREPARATION OF NANOSIZED METAL OXIDE PARTICLES.
Abstract	This invention relates to a process for the preparation of nanosized metal oxide particles having a size in the range of 10 to 120 nm, comprising: mixing at least one metal nitrate such as herein described, fuel and minor amount of polyvinyl alcohol in aqueous medium to obtain a homogeneous mixture, said metal nitrate, fuel and polyvinyl alcohol being mixed in a ratio of 1:1 to 3:0.0.5 to 4; drying or spray drying the said mixture to obtain fluffy carbonaceous mass; calcining the said carbonaceous mass at a temperature range depending on the chemical nature of the system to produce the desired nanosized product.

Title of Invention

A PROCESS OF PREPARATION OF NANOSIZED METAL OXIDE PARTICLES.

Abstract

This invention relates to a process for the preparation of nanosized metal oxide particles having a size in the range of 10 to 120 nm, comprising: mixing at least one metal nitrate such as herein described, fuel and minor amount of polyvinyl alcohol in aqueous medium to obtain a homogeneous mixture, said metal nitrate, fuel and polyvinyl alcohol being mixed in a ratio of 1:1 to 3:0.0.5 to 4; drying or spray drying the said mixture to obtain fluffy carbonaceous mass; calcining the said carbonaceous mass at a temperature range depending on the chemical nature of the system to produce the desired nanosized product.

Full Text	This invention relates to a process of preparation of nanosized metal oxide particles. BACKGROUND OF THE INVENTION Previously, fuel based nano particles was synthesized by using hydrazine based pyrophoric chemicals. The method of the prior art had several disadvantages, like toxicity of the reagents and difficulty in controlling high exothermic process and homogeneity of the multicomponent mixture. OBJECTS OF THE INVENTION An object of this invention is to propose a novel process of preparation of nanosized oxide particles. Another object of this invention is to propose a process whose rate of reaction can be smoothly controlled for getting desired morphology of the particles. Yet another object of this invention is to propose a cheaper process for the preparation of nanosized metal oxide particles. Yet another object of this invention is to propose am environment friendly process. Other objects and advantages of the invention Mill be apparent from the ensuing description. DETAILED DESCRIPTION OF THE INVENTION According to this invention is provided a process for the prepa- ration of nanosized metal oxide particles comprising mixing atleast one metal nitrate, fuel and minor amount of polyvinyl alcohol in aqueous medium to obtain a homogeneous mixture; drying or spray drying the said mixture to obtain fluffy carbo- naceous mass; calcining the said carbonaceous mass at a temperature range depending on the chemical nature of the system to produce the desired nanosized product. In accordance with this invention, the solar ratio of metal nitrate, fuel and polyvinyl alcohol (PVA) in the homogeneous mix- ture is l:l to 3:0.05 to 4 where the mole ratio of fuel is calcu- lated with respect to the monomer unit. When the fuel is hydro- lysed starch, the formula weight is taken corresponding to C6H12O6. The homogeneous mixture obtained is dried or spray dried at a temperature in the range off 100 to 200 C to obtain a fluffy car- bonaceous mass, which is calcined at a temperature range of 200 to 600oC to obtain the desired nanosized metal oxide particles. The metal nitrate is selected from compounds such as aluminium nitrate, titanium nitrate, chromium nitrate, zirconium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, manganese nitrate, cobalt nitrate, mickel nitrate, copper nitrate, zinc nitrate, cadmium nitrate, galium nitrate, indium nitrate, ferric nitrate, ruthenium nitrate, rhodium nitrate, lead nitrate, barium nitrate, hafnium nitrate, lanthanum nitrate, cerium nitrate, pra- seodymium nitrate, neadymium nitrate, samarium nitrate, gadoli- nium nitrate, europeum nitrate, holmium nitrate, erbium nitrate, niobium nitrate, tantalum nitrate, tungsten nitrate, nitrates of rare—earth elements, singly or in mixtures. The fuel used in the present invention is selected from xylose, glucose, fructose, sucrose, hydrolysed starch, sorbitol and manitol. The particle size of the nanosized metal oxide particles is within a range of 10 to 120 nm. The following nanosized metal oxides can be prepared by the aforesaid process : i. Pure oxide [l-Al O , TiO , Cr O , ZrO , ZrO (partially stabi- 2 3 2 2 3 2 2 lized by CaO, MgO, Y O , CeO )J, having a particle size in the 2 3 2 range off 10 to 80 nm; ii. (AB 0), [where A = Mg, Ca, Sr, Mn, Fe, Co, Ni, Cu, Zn, Cd 2 4 and mixtures; B = A1, 6a, In, Cr, Fe, Co, Ru, Rh and mixtures], having a particle size in the range of 10 to 80 nm; iii-a- ABO where [A = Ca, Sr, Pb, Ba, Zn, Cd and mix tores; B = 3 Ti, Zr, Hf and mixtures] and [A = La, Ce, Pr, Nd, Sm, Gd, Eu, Ho, Er and mixtures; & = Fe, Cr, Mn and mixtures], having a particle size in the range of 20 to 1.20 nm; b. A(B B )0 [where A = Pb, Ba, Cd and mixtures, B = Mg, Zn, x 1—x Ni, Co, Fe, Cu, B = Ti, Zr, Nb, Ta, W and Mixtures; and x = 1/2, 1/33, having a particle size in the range of 30 to 120 nm; iv. (A B O ), [where A = y, rare—earth elements and Mixtures; 3 5 12 and B = Fe, A1, Cr, Mn and mixtures], having a particle size in the range of 25 to 129 nm; +m -n v. Nano—composites (xA 0 (1-x)B 0 ], [where A = A1, Zr, m/2, n/2 and mixtures; aimcB B — Fe, Cr, Cu, Min, Co, Ni and mixtures; and x = 0.05 to 0.95], having a particle in the range of 20 to 90 nm. Further, the fuel used in the present invention is selected from xylose, glucose, fructose, sucrose, hydrolyzed starch, sorbitol and manitol. This Invention will now be explained in greater detail with the help of the following non—limiting examples. EXAMPLE 1 -£(-Al 0 2 3 1 mole (Al(NO )), 9H 0 (FW 375} and 2 mole sucrose FW 342) were 3 3 2 dissolved in 1.5 ltr. distilled water. In this mixture, 0.05 mole PVA (molecular weight with respect to monomer) was added as 10% w/v aqueous solution and the resulting solution were evaporated o by heating on a hot plate at 180 C. At the time of evaporation, the nitrates were decomposed and brown fumes of nitrogen dioxide gas was evolved. After complete evaporation, a voluminous fluffy organic based) precursor powder was resulted. This precursor o powder on calcination at 11100 C or 2 hrs. produced £— Al 0 2 3 powder average particle size less than 60 nm. EXAMPLE 2 - LaAIO 3 Aqueous solution of lanthanum nitrate was prepared by reacting 0.5 mole La O (FW 325.8) with 3 mole aqueous nitric acid solution 2 3 (75% v/v). Then this aqueous solution of lanthanum nitrate was mixed with 2.5 ltr. of boiling solutions containing 1 mole A1(NO ) 3 3 9H 0 (FM 375) and 4 mole sucrose (FW 342). In this mixture, 0.05 2 mole PVA was added as l0% w/v aqueous solution. The resulting solution were then evaporated toy heating on a hot plate at 150oC. At the time of ewaporation, the nitrates were decomposed and brown fumes of nitrogen dioxide gas was evolved. After complete evaporation, a voluminous fluffy organic based precursor powder was resulted. This precursor powder on calcination at 700OC for 2 hrs. produtced single phase LaA10 powder with the particle size 3 ranging from 50—60 nm. EXAMPLE 3 - Partially stabilized ZrO 2 1 mole zirconium hydroxide was prepared by adding ammonium hydroxidle to aqueous solution of zirconium—oxychloride hexahy- drate (1 mole in 1 ltr). This zirconium hydroxide was filtered and washed with distilled water- 1 mole zirconium hydroxide was dissolved in 1 ltr. concentrated nitric acid. Y O (0.04 mole) 2 3 was dissolved in concentrated nitric acid solution (50cc). These two solutions were then mixed. In this mixture, 2.5 mole sucrose was added and water was added so that the total volume became 2.5 ltr.. In this mixture, 0.05 mole PVA was added as 10% w/v aqueous solution- The resulting solution were then evaporated by heating o on a hot plate at 150 C. At the time of evaporation, the nitrates were decomposed and brown fumes of nitrogen dioxide gas was evolved. After complete evaporation, a voluminous fluffy organic based precursor powder was resulted. This precursor powder on calcination at 1200OC for 1 hr. produced the yttria stabilized ZrO powder with average particle size less than 80 nm. 2 EXAMPLE 4 - Pb(Zr Ti )0 0.5 0.5 3 1 mole Pb(NO) and 0.5 mole Ti0(NO ) and 0.5 mole ZrC (NO ) were 3 2 3 2 3 2 dissolved in separately 1 ltr. water and then these were mixed up. In this Mixture, 4 mole sucrose was added and water was added so that the total volume became 4 ltr.. In this mixture, 0.05 mole PVA (with respect to monomer unit) was added as 10% w/v aqueous solution. The resulting solution were then evaporated by heating. At the time of evaporation, the nitrates were decomposed and brown fumes of nitrogen dioxide gas was evolved. After complete evaporation, a voluminous fluffy organic based precursor powder was resulted. This precursor powder on calcination at 600 C for 2 hrs. produced the single phase Pb(Zr Ti )0 powder with 0.5 0.5 3 average particle size less than 120 nm. WE CLAIM; 1. A process for the preparation of nanosized metal oxide particles having a size in the range of 10 to 120 nm, comprising: mixing at least one metal nitrate such as herein described, fuel and minor amount of polyvinyl alcohol in aqueous medium to obtain a homogeneous mixture, said metal nitrate, fuel and polyvinyl alcohol being mixed in a ratio of 1:1 to 3:0.05 to 4; drying or spray drying the said mixture to obtain fluffy carbon- aceous mass; calcining the said carbonaceous mass at a temperature range depending on the chemical nature of the system to produce the desired nanosized product. 2. The process as claimed in claim 1 wherein said homogenous mixture is dried or spray dried at a temperature in the range of o 100 to 200 C. 3. The process as claimed in claim 1 wherein said carbonaceous mass is calcined at a temperature in the range of o 200 to 600 C. 4. The process as claimed in claim 1 wherein said metal nitrate is selected from aluminium nitrate, titanium nitrate chromium nitrate, zirconium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, manganese nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, cadmium nitrate, galium nitrate, indium nitrate, ferric nitrate, ruthenium nitrate, rhodium nitrate, lead nitrate, barium nitrate, hafnium nitrate, lanthanum nitrate, cerium nitrate, praseodymium nitrate, neodymium nitrate, samarium nitrate, gadolinium nitrate, europeum nitrate, holmium nitrate, erbium nitrate, niobium nitrate, tantalum nitrate, tungsten nitrate, nitrates of rare- earth elements, singly or in mixtures. 5. The process as claimed in claim 1 wherein said fuel is selected from xylose, glucose, fructose, sucrose, hydrolysed starch, sorbitol and manitol. 6. The process as claimed in claim 1 wherein the size of the nanosized metal oxide particles is in the range of 10 to 80 nm. 7. The process as claimed in claim 1 wherein the size of the nanosized metal oxide particles is in the range of 20 to 120 nm. 3. The process as claimed in claim 1 wherein the size of the nanosized metal oxide particles is in the range of 30 to 120 nm. 9. The process as claimed in claim 1 wherein the size of the nanosized metal oxide particles is in the range of 25 to 120 nm. 10. The process as claimed in claim 1 wherein the size of the nanosized metal oxide particles is in the range of 20 to 90 nm. This invention relates to a process for the preparation of nanosized metal oxide particles having a size in the range of 10 to 120 nm, comprising: mixing at least one metal nitrate such as herein described, fuel and minor amount of polyvinyl alcohol in aqueous medium to obtain a homogeneous mixture, said metal nitrate, fuel and polyvinyl alcohol being mixed in a ratio of 1:1 to 3:0.05 to 4; drying or spray drying the said mixture to obtain fluffy carbonaceous mass; calcining the said carbonaceous mass at a temperature range depending on the chemical nature of the system to produce the desired nanosized product.

Full Text

This invention relates to a process of preparation of nanosized
metal oxide particles.
BACKGROUND OF THE INVENTION
Previously, fuel based nano particles was synthesized by using
hydrazine based pyrophoric chemicals. The method of the prior art
had several disadvantages, like toxicity of the reagents and
difficulty in controlling high exothermic process and homogeneity
of the multicomponent mixture.
OBJECTS OF THE INVENTION
An object of this invention is to propose a novel process of
preparation of nanosized oxide particles.
Another object of this invention is to propose a process whose
rate of reaction can be smoothly controlled for getting desired
morphology of the particles.
Yet another object of this invention is to propose a cheaper
process for the preparation of nanosized metal oxide particles.
Yet another object of this invention is to propose am environment
friendly process.
Other objects and advantages of the invention Mill be apparent
from the ensuing description.
DETAILED DESCRIPTION OF THE INVENTION
According to this invention is provided a process for the prepa-
ration of nanosized metal oxide particles comprising mixing
atleast one metal nitrate, fuel and minor amount of polyvinyl
alcohol in aqueous medium to obtain a homogeneous mixture;
drying or spray drying the said mixture to obtain fluffy carbo-
naceous mass;
calcining the said carbonaceous mass at a temperature range
depending on the chemical nature of the system to produce the
desired nanosized product.
In accordance with this invention, the solar ratio of metal
nitrate, fuel and polyvinyl alcohol (PVA) in the homogeneous mix-
ture is l:l to 3:0.05 to 4 where the mole ratio of fuel is calcu-
lated with respect to the monomer unit. When the fuel is hydro-
lysed starch, the formula weight is taken corresponding to C6H12O6.
The homogeneous mixture obtained is dried or spray dried at a
temperature in the range off 100 to 200 C to obtain a fluffy car-
bonaceous mass, which is calcined at a temperature range of 200
to 600oC to obtain the desired nanosized metal oxide particles.
The metal nitrate is selected from compounds such as aluminium
nitrate, titanium nitrate, chromium nitrate, zirconium nitrate,
magnesium nitrate, calcium nitrate, strontium nitrate, manganese
nitrate, cobalt nitrate, mickel nitrate, copper nitrate, zinc
nitrate, cadmium nitrate, galium nitrate, indium nitrate, ferric
nitrate, ruthenium nitrate, rhodium nitrate, lead nitrate, barium
nitrate, hafnium nitrate, lanthanum nitrate, cerium nitrate, pra-
seodymium nitrate, neadymium nitrate, samarium nitrate, gadoli-
nium nitrate, europeum nitrate, holmium nitrate, erbium nitrate,
niobium nitrate, tantalum nitrate, tungsten nitrate, nitrates of
rare—earth elements, singly or in mixtures.
The fuel used in the present invention is selected from xylose,
glucose, fructose, sucrose, hydrolysed starch, sorbitol and
manitol.
The particle size of the nanosized metal oxide particles is
within a range of 10 to 120 nm.
The following nanosized metal oxides can be prepared by the
aforesaid process :
i. Pure oxide [l-Al O , TiO , Cr O , ZrO , ZrO (partially stabi-
2 3 2 2 3 2 2
lized by CaO, MgO, Y O , CeO )J, having a particle size in the
2 3 2
range off 10 to 80 nm;
ii. (AB 0), [where A = Mg, Ca, Sr, Mn, Fe, Co, Ni, Cu, Zn, Cd
2 4
and mixtures; B = A1, 6a, In, Cr, Fe, Co, Ru, Rh and mixtures],
having a particle size in the range of 10 to 80 nm;
iii-a- ABO where [A = Ca, Sr, Pb, Ba, Zn, Cd and mix tores; B =
3
Ti, Zr, Hf and mixtures] and [A = La, Ce, Pr, Nd, Sm, Gd, Eu, Ho,
Er and mixtures; & = Fe, Cr, Mn and mixtures], having a particle
size in the range of 20 to 1.20 nm;
b. A(B B )0 [where A = Pb, Ba, Cd and mixtures, B = Mg, Zn,
x 1—x
Ni, Co, Fe, Cu, B = Ti, Zr, Nb, Ta, W and Mixtures; and x = 1/2,
1/33, having a particle size in the range of 30 to 120 nm;
iv. (A B O ), [where A = y, rare—earth elements and Mixtures;
3 5 12
and B = Fe, A1, Cr, Mn and mixtures], having a particle size in
the range of 25 to 129 nm;
+m -n
v. Nano—composites (xA 0 (1-x)B 0 ], [where A = A1, Zr,
m/2, n/2
and mixtures; aimcB B — Fe, Cr, Cu, Min, Co, Ni and mixtures; and x
= 0.05 to 0.95], having a particle in the range of 20 to 90 nm.
Further, the fuel used in the present invention is selected from
xylose, glucose, fructose, sucrose, hydrolyzed starch, sorbitol
and manitol.
This Invention will now be explained in greater detail with the
help of the following non—limiting examples.
EXAMPLE 1 -£(-Al 0
2 3
1 mole (Al(NO )), 9H 0 (FW 375} and 2 mole sucrose FW 342) were
3 3 2
dissolved in 1.5 ltr. distilled water. In this mixture, 0.05 mole
PVA (molecular weight with respect to monomer) was added as 10%
w/v aqueous solution and the resulting solution were evaporated
o
by heating on a hot plate at 180 C. At the time of evaporation,
the nitrates were decomposed and brown fumes of nitrogen dioxide
gas was evolved. After complete evaporation, a voluminous fluffy
organic based) precursor powder was resulted. This precursor
o
powder on calcination at 11100 C or 2 hrs. produced £— Al 0
2 3
powder average particle size less than 60 nm.
EXAMPLE 2 - LaAIO
3
Aqueous solution of lanthanum nitrate was prepared by reacting
0.5 mole La O (FW 325.8) with 3 mole aqueous nitric acid solution
2 3
(75% v/v). Then this aqueous solution of lanthanum nitrate was
mixed with 2.5 ltr. of boiling solutions containing 1 mole A1(NO )
3 3
9H 0 (FM 375) and 4 mole sucrose (FW 342). In this mixture, 0.05
2
mole PVA was added as l0% w/v aqueous solution. The resulting

solution were then evaporated toy heating on a hot plate at 150oC.
At the time of ewaporation, the nitrates were decomposed and
brown fumes of nitrogen dioxide gas was evolved. After complete
evaporation, a voluminous fluffy organic based precursor powder

was resulted. This precursor powder on calcination at 700OC for 2
hrs. produtced single phase LaA10 powder with the particle size
3
ranging from 50—60 nm.
EXAMPLE 3 - Partially stabilized ZrO
2
1 mole zirconium hydroxide was prepared by adding ammonium
hydroxidle to aqueous solution of zirconium—oxychloride hexahy-
drate (1 mole in 1 ltr). This zirconium hydroxide was filtered
and washed with distilled water- 1 mole zirconium hydroxide was
dissolved in 1 ltr. concentrated nitric acid. Y O (0.04 mole)
2 3
was dissolved in concentrated nitric acid solution (50cc). These
two solutions were then mixed. In this mixture, 2.5 mole sucrose
was added and water was added so that the total volume became 2.5
ltr.. In this mixture, 0.05 mole PVA was added as 10% w/v aqueous
solution- The resulting solution were then evaporated by heating
o
on a hot plate at 150 C. At the time of evaporation, the nitrates
were decomposed and brown fumes of nitrogen dioxide gas was
evolved. After complete evaporation, a voluminous fluffy organic
based precursor powder was resulted. This precursor powder on

calcination at 1200OC for 1 hr. produced the yttria stabilized
ZrO powder with average particle size less than 80 nm.
2
EXAMPLE 4 - Pb(Zr Ti )0
0.5 0.5 3
1 mole Pb(NO) and 0.5 mole Ti0(NO ) and 0.5 mole ZrC (NO ) were
3 2 3 2 3 2
dissolved in separately 1 ltr. water and then these were mixed
up. In this Mixture, 4 mole sucrose was added and water was added
so that the total volume became 4 ltr.. In this mixture, 0.05
mole PVA (with respect to monomer unit) was added as 10% w/v
aqueous solution. The resulting solution were then evaporated by
heating. At the time of evaporation, the nitrates were decomposed
and brown fumes of nitrogen dioxide gas was evolved. After
complete evaporation, a voluminous fluffy organic based precursor
powder was resulted. This precursor powder on calcination at 600 C
for 2 hrs. produced the single phase Pb(Zr Ti )0 powder with
0.5 0.5 3
average particle size less than 120 nm.
WE CLAIM;
1. A process for the preparation of nanosized metal oxide
particles having a size in the range of 10 to 120 nm, comprising:
mixing at least one metal nitrate such as herein described, fuel
and minor amount of polyvinyl alcohol in aqueous medium to obtain
a homogeneous mixture, said metal nitrate, fuel and polyvinyl
alcohol being mixed in a ratio of 1:1 to 3:0.05 to 4;
drying or spray drying the said mixture to obtain fluffy carbon-
aceous mass;
calcining the said carbonaceous mass at a temperature range
depending on the chemical nature of the system to produce the
desired nanosized product.
2. The process as claimed in claim 1 wherein said homogenous
mixture is dried or spray dried at a temperature in the range of
o
100 to 200 C.
3. The process as claimed in claim 1 wherein said
carbonaceous mass is calcined at a temperature in the range of
o
200 to 600 C.
4. The process as claimed in claim 1 wherein said metal
nitrate is selected from aluminium nitrate, titanium nitrate
chromium nitrate, zirconium nitrate, magnesium nitrate, calcium
nitrate, strontium nitrate, manganese nitrate, cobalt nitrate,
nickel nitrate, copper nitrate, zinc nitrate, cadmium nitrate,
galium nitrate, indium nitrate, ferric nitrate, ruthenium
nitrate, rhodium nitrate, lead nitrate, barium nitrate, hafnium
nitrate, lanthanum nitrate, cerium nitrate, praseodymium
nitrate, neodymium nitrate, samarium nitrate, gadolinium nitrate,
europeum nitrate, holmium nitrate, erbium nitrate, niobium
nitrate, tantalum nitrate, tungsten nitrate, nitrates of rare-
earth elements, singly or in mixtures.
5. The process as claimed in claim 1 wherein said fuel is
selected from xylose, glucose, fructose, sucrose, hydrolysed
starch, sorbitol and manitol.
6. The process as claimed in claim 1 wherein the size of the
nanosized metal oxide particles is in the range of 10 to 80 nm.
7. The process as claimed in claim 1 wherein the size of the
nanosized metal oxide particles is in the range of 20 to 120 nm.
3. The process as claimed in claim 1 wherein the size of the
nanosized metal oxide particles is in the range of 30 to 120 nm.
9. The process as claimed in claim 1 wherein the size of the
nanosized metal oxide particles is in the range of 25 to 120 nm.
10. The process as claimed in claim 1 wherein the size of the
nanosized metal oxide particles is in the range of 20 to 90 nm.
This invention relates to a process for the preparation of
nanosized metal oxide particles having a size in the range of 10
to 120 nm, comprising:
mixing at least one metal nitrate such as herein described, fuel
and minor amount of polyvinyl alcohol in aqueous medium to obtain
a homogeneous mixture, said metal nitrate, fuel and polyvinyl
alcohol being mixed in a ratio of 1:1 to 3:0.05 to 4;
drying or spray drying the said mixture to obtain fluffy carbonaceous
mass;
calcining the said carbonaceous mass at a temperature range
depending on the chemical nature of the system to produce the
desired nanosized product.

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Patent Number

216873

Indian Patent Application Number

1664/CAL/1998

PG Journal Number

12/2008

Publication Date

21-Mar-2008

Grant Date

19-Mar-2008

Date of Filing

17-Sep-1998

Name of Patentee

INDIAN INSTITUTE OF TECHNOLOGY

Applicant Address

KHARAGPUR 721 302

Inventors:

#	Inventor's Name	Inventor's Address
1	PROF. P. PRAMANIK	DEPARTMENT LOF CHEMISTRY, INDIAN INSTITUTE OF TECHNOLOGY, KHARAGPUR 721 302

PCT International Classification Number

C 01 B 13/14

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA