CA1166600A - Process for preparing ceric sulphate - Google Patents
Process for preparing ceric sulphateInfo
- Publication number
- CA1166600A CA1166600A CA000363336A CA363336A CA1166600A CA 1166600 A CA1166600 A CA 1166600A CA 000363336 A CA000363336 A CA 000363336A CA 363336 A CA363336 A CA 363336A CA 1166600 A CA1166600 A CA 1166600A
- Authority
- CA
- Canada
- Prior art keywords
- sulphate
- cerous
- current density
- mamp
- cerous sulphate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F17/00—Compounds of rare earth metals
- C01F17/20—Compounds containing only rare earth metals as the metal element
- C01F17/282—Sulfates
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process for preparing ceric sulphate in solu-tion. A saturated solution of cerous sulphate is electro-lyzed at high anodic current density, high cathode current density and with vigorous agitation in the presence of dilute sulphuric acid. The process permits the production of concentrated ceric sulphate solutions at commercially viable current densities and efficiencies.
A process for preparing ceric sulphate in solu-tion. A saturated solution of cerous sulphate is electro-lyzed at high anodic current density, high cathode current density and with vigorous agitation in the presence of dilute sulphuric acid. The process permits the production of concentrated ceric sulphate solutions at commercially viable current densities and efficiencies.
Description
This invention relates to a process for preparing ceric sulphate.
The use of cerium oxidants, for example ceric sulphate, is well known in organic chemistry. Ceric sul-phate can be used to prepare naphthoquinone from naphtha-lene, p-tolualdehyde from p-xylene and benzaldehyde from toluene.
In preparing a cerium oxidant for use in organic snythesis it is important to prepare the oxidant in as concentrated a form as possible. This is necessary to increase reaction rates and reduce reactor size requirements and manufacturing costs.
Kuhn in the Electrochemistry of Lead published by the Academic Press in 1979, summarizes the prior art in the oxidation of cerium (III) to cerium (IV). It is indicated that prior workers such as Ramaswamy et al, Bull. Chem. Soc.
Jap. 35, 1751 (1962), and Ishino et al, Technol. Rep., Osaka University. 10, 261 (1960), have observed that the current efficiency for ceric sulphate production decreases with increasing concentration of sulphuric acid, for example 0.26 to 2.6 molar, and with increasing current density, for example 1 to 3.0 amps/dm2, i.e. 10 to 30 mamp/cm . The current efficiency of ceric sulphate production was only 54%
at an anode current density of 1 amp/dm2 (10 mamp/cm2). The "effective" anode current density was therefore only 5.4 mamp/cm2. Ishino et al. found the best electrolysis con-ditions to be low anodic current density, for example 2 Amp/dm2 (i.e. 20 mamp/cm2), and low sulphuric acid con-centration, for example 0.43M sulphuric acid.
r~
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The prior art fails to reveal how ceric sulphate can be prepared in a concentrated form and at commercially viable current densities, for example 100 mamp/cm2, and commercially viable current efficiencies, for example 50~, to give "effective" anode current densities of 50 mamp/cm2 or higher.
Kuhn, in the above publication, specifically indicates that little information is available for the reaction of oxidizing cerium (III) to cerium (IV).
However, the present application describes a process able to achieve extremely high current efficiencies for concentrated ceric sulphate preparation and very high effective anode current densities using a wide variety of anodes and cathodes and~acid strengths deemed detrimental by others, specifically Ramaswamy et al and Ishino et al.
More specifically, the present invention is a process for preparing ceric sulphate in solution that comprises electrolyzing an at least saturated solution of cerous sulphate at an anodic of or greater than 100 mamp/cm2 cathode current density of or greater than 1000 mamp/cm2 and with vigorous agitation in the presence of 1 to 2 molar sulphuric acid in the absence of a diaphragm.
The saturated cerous sulphate may be maintained as such by electrolyzing a suspension of cerous sulphate, or by carrying out the electrolysis of a saturated cerous sulphate solution. A diaphragm is not used. The electrolysis of a saturated cerous sulphate solution is carried out briefly then the electrolyte is mixed with cerous sulphate crystals to resaturate it with respect to cerous sulphate. Undissol-ved cerous sulphate crystals are allowed to precipitate.
~l , llf~i`7~UU
The supernatant liquid is then re-electrolyzed.
The invention is illustrated in the following examples:
Examples Exeept where indicated otherwise in Table 1 electrolysis of a starting eleetrolyte comprising 25 grams of eerous sulpha~e pentahydrate, 5.5 ml of eoneentrated sulphurie aeid diluted to a volume of 100 ml with water to give lM sulphuric acid was carried out with vigorous agi-tation of the electrolyte during eleetrolysis. The results and reaction conditions are set out in Table 1. A diaphragm was not used in the eleetrolysis.
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o In addition to the above experiments illustrating the present invention experiments were carried out to attempt to reproduce the results of Ramaswamy et al, re-ferred to above, by using an anodized lead anode and a lead cathode at current densities of 20 mamp/cm2 and 300 mamp/cm2 respectively using the electrolyte, electrolysis cell and electrolyte agitation defined in Table 1 above. Table 2 below summarizes the current efficiencies obtained during this experiment as a function of ceric ion concentration of the electrolyte.
V
Ir) N
Nt`
~O .
oo a~
O
~. . ~
N1`~, ~~ I` O
N .
O~ ~
~r ~co o O Ne~
l_ . .
Ll~ .
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N O~ ,~
E~ ~ Il') c5~ o d~ d~a~
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Na~ a~ O
o\oo~o ~ ~ N
~ . .
or~
Na~ 0 ~ ~ o a u~
~-~
o ~
s~o o ~
a)-" o a) o Et The results show that applicant was unable to generate ceric sulphate above 0.37M concentration by opera-ting at a low anodic current density, that is 20mamp/cm and a low cathode current density of 300mamp/cm using Ramaswamy et al's suggested electrolysis conditions.
Further, once the ceric sulphate concentration approaches 0.3 molar the anodic current e~ficiency began to drop rapidly. Inspection of the lead cathode used in this electrolysis revealed that it was covered with a thick deposit of lead. This depositicn has not been observed during the high current density electrolysis described in Table 1 and has the following significance:
1. The fact that lead is plated on ~he cathode indicates that the lead dioxide film on the anodized lead anode is not stable during low current density electrolysis once the ceric ion concentration of the electrolyte builds up much above 0.3 molar concen-tration.
The use of cerium oxidants, for example ceric sulphate, is well known in organic chemistry. Ceric sul-phate can be used to prepare naphthoquinone from naphtha-lene, p-tolualdehyde from p-xylene and benzaldehyde from toluene.
In preparing a cerium oxidant for use in organic snythesis it is important to prepare the oxidant in as concentrated a form as possible. This is necessary to increase reaction rates and reduce reactor size requirements and manufacturing costs.
Kuhn in the Electrochemistry of Lead published by the Academic Press in 1979, summarizes the prior art in the oxidation of cerium (III) to cerium (IV). It is indicated that prior workers such as Ramaswamy et al, Bull. Chem. Soc.
Jap. 35, 1751 (1962), and Ishino et al, Technol. Rep., Osaka University. 10, 261 (1960), have observed that the current efficiency for ceric sulphate production decreases with increasing concentration of sulphuric acid, for example 0.26 to 2.6 molar, and with increasing current density, for example 1 to 3.0 amps/dm2, i.e. 10 to 30 mamp/cm . The current efficiency of ceric sulphate production was only 54%
at an anode current density of 1 amp/dm2 (10 mamp/cm2). The "effective" anode current density was therefore only 5.4 mamp/cm2. Ishino et al. found the best electrolysis con-ditions to be low anodic current density, for example 2 Amp/dm2 (i.e. 20 mamp/cm2), and low sulphuric acid con-centration, for example 0.43M sulphuric acid.
r~
UO
The prior art fails to reveal how ceric sulphate can be prepared in a concentrated form and at commercially viable current densities, for example 100 mamp/cm2, and commercially viable current efficiencies, for example 50~, to give "effective" anode current densities of 50 mamp/cm2 or higher.
Kuhn, in the above publication, specifically indicates that little information is available for the reaction of oxidizing cerium (III) to cerium (IV).
However, the present application describes a process able to achieve extremely high current efficiencies for concentrated ceric sulphate preparation and very high effective anode current densities using a wide variety of anodes and cathodes and~acid strengths deemed detrimental by others, specifically Ramaswamy et al and Ishino et al.
More specifically, the present invention is a process for preparing ceric sulphate in solution that comprises electrolyzing an at least saturated solution of cerous sulphate at an anodic of or greater than 100 mamp/cm2 cathode current density of or greater than 1000 mamp/cm2 and with vigorous agitation in the presence of 1 to 2 molar sulphuric acid in the absence of a diaphragm.
The saturated cerous sulphate may be maintained as such by electrolyzing a suspension of cerous sulphate, or by carrying out the electrolysis of a saturated cerous sulphate solution. A diaphragm is not used. The electrolysis of a saturated cerous sulphate solution is carried out briefly then the electrolyte is mixed with cerous sulphate crystals to resaturate it with respect to cerous sulphate. Undissol-ved cerous sulphate crystals are allowed to precipitate.
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The supernatant liquid is then re-electrolyzed.
The invention is illustrated in the following examples:
Examples Exeept where indicated otherwise in Table 1 electrolysis of a starting eleetrolyte comprising 25 grams of eerous sulpha~e pentahydrate, 5.5 ml of eoneentrated sulphurie aeid diluted to a volume of 100 ml with water to give lM sulphuric acid was carried out with vigorous agi-tation of the electrolyte during eleetrolysis. The results and reaction conditions are set out in Table 1. A diaphragm was not used in the eleetrolysis.
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o In addition to the above experiments illustrating the present invention experiments were carried out to attempt to reproduce the results of Ramaswamy et al, re-ferred to above, by using an anodized lead anode and a lead cathode at current densities of 20 mamp/cm2 and 300 mamp/cm2 respectively using the electrolyte, electrolysis cell and electrolyte agitation defined in Table 1 above. Table 2 below summarizes the current efficiencies obtained during this experiment as a function of ceric ion concentration of the electrolyte.
V
Ir) N
Nt`
~O .
oo a~
O
~. . ~
N1`~, ~~ I` O
N .
O~ ~
~r ~co o O Ne~
l_ . .
Ll~ .
CO O
o\ o\ N
N ~1~1 a~ . .
N O~ ,~
E~ ~ Il') c5~ o d~ d~a~
CO OCO
N . N
Na~ a~ O
o\oo~o ~ ~ N
~ . .
or~
Na~ 0 ~ ~ o a u~
~-~
o ~
s~o o ~
a)-" o a) o Et The results show that applicant was unable to generate ceric sulphate above 0.37M concentration by opera-ting at a low anodic current density, that is 20mamp/cm and a low cathode current density of 300mamp/cm using Ramaswamy et al's suggested electrolysis conditions.
Further, once the ceric sulphate concentration approaches 0.3 molar the anodic current e~ficiency began to drop rapidly. Inspection of the lead cathode used in this electrolysis revealed that it was covered with a thick deposit of lead. This depositicn has not been observed during the high current density electrolysis described in Table 1 and has the following significance:
1. The fact that lead is plated on ~he cathode indicates that the lead dioxide film on the anodized lead anode is not stable during low current density electrolysis once the ceric ion concentration of the electrolyte builds up much above 0.3 molar concen-tration.
2. If the anode is unstable, current is being wasted in the following possible ways:
(a) Ceric ion in the electrolyte de-composes by reacting with lead atoms to form lead (11) ions which migrate to the cathode and plate out.
i.e. 2Ce4 + Pb 2Ce3+ + pb2 (anode) Pb + 2e- Pb ~cathode) o The overall reaction is:
2Ce4+ + 2e~- 2Ce3+
(b) The lead dioxide film produced by anodizing the lead electrode is not sufficiently polarized at low current densities to prevent its being decomposed by sulphuric acid to form lead sul-phate.
2 2 4 2e ~ PbS04 + 2H20 If the lead dioxide (PbO2) film is lost in whole or part, the anode is incapable of generating ceric sulphate and the underlying lead is susceptible to attack by ceric sulphate generated previously.
(a) Ceric ion in the electrolyte de-composes by reacting with lead atoms to form lead (11) ions which migrate to the cathode and plate out.
i.e. 2Ce4 + Pb 2Ce3+ + pb2 (anode) Pb + 2e- Pb ~cathode) o The overall reaction is:
2Ce4+ + 2e~- 2Ce3+
(b) The lead dioxide film produced by anodizing the lead electrode is not sufficiently polarized at low current densities to prevent its being decomposed by sulphuric acid to form lead sul-phate.
2 2 4 2e ~ PbS04 + 2H20 If the lead dioxide (PbO2) film is lost in whole or part, the anode is incapable of generating ceric sulphate and the underlying lead is susceptible to attack by ceric sulphate generated previously.
3. If lead electrodeposits on the cathode, the cathode current density is reduced and ceric sulphate decomposition is enhanced according to the following reaction:
Ce4+ + le ~ Ce3+
All three factors alone or in combina-tion can have a disastrous effect on current efficiency for ceric ion pro-duction as is evident from Table 2.
~i~66(J 0 The above problems can be avoided if a platinum anode is used instead of the lead dioxide anode used in Table 2. However, the use of platinum at low current densities of 20 mamp/cm2 is too expensive.
Thus the present invention has illustrated that high current efficiencies obtained at high "effective"
current densities and high ceric sulphate concentration when electrolysis is carried out at high anodic and cathodic current densities. It is important to maintain the maximum dissolved cerous ion concentration in the electrolyte for the entire electrolysis.
SUPPLEMENTARY DISCLOSURE
Further work done on the invention described in the principal disclosure has indicated that the process there described is of a broader aspect. According to the further work the present invention is a process for prepa-ring ceric sulphate in solution that comprises electrolysing an at least saturated solution of ceric sulphate at an anodic current density in the range 100 to 400 mamp/cm2, a cathode current density in the range 1,000 to 4,500 mamp/cm2 and with vigorous agitation in the presence of dilute sulphuric acid.
As in the principal disclosure the saturated cerous sulphate may be maintained as such by electrolyzing a suspension of cerous sulphate, or by carrying out the electrolysis of a saturated cerous sulphate solution. A
diaphragm is not used. The electrolysis of a saturated cerous sulphate solution is carried out briefly then the electrolyte is mixed with cerous sulphate crystals to resaturate it with respect to cerous sulphate. Undissolved cerous sulphate crystals are allowed to precipitate. The super-natant liquid is then re-electrolyzed.
The following examples illustrate this development:
Examples Except where indicated otherwise in Table 3 elec-trolysis of a starting electrolyte comprising 25 grams of cerous sulphate pentahydrate, 6.6 ml. of concentrated sulphuric acid diluted to a volume of 100 ml with water to give lM
sulphuric acid was carried out with vigorous agitation of the electrolyte during electrolysis. The results and reaction conditions are set out in Table 1. A diaphragm was not used in the electrolysis.
_ ~ _ 11~
o~ ~ u~
a~ 0 O~ ~ Ir) o~
' ~ a ~ ~ O ~ ~ ~ ~ O ~1 1` 0 C~ ~ ~ ~ 0 ~ ~ u~ ~ ~ u~
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Thus the invention of this supplementary disclosure, like the invention of the principal dlsclosure, has illus-trated that high current efficiencies are obtained at high "effective" current densities and high ceric sulphate con-centration when electrolysis is carried out at high anodic and cathodic current densities. Again it is important to maintain the maximum dissolved cerous ion concentration in the electrolyte for the entire electrolysis. With regard to the present process the generally higher molarities of the final ceric sulphate should be noted.
Further information applicable to the present application is:
Cathode current densities much in excess of 4500 mamp/cm2 (e.g. 6000-8000 mamp/cm2) may result in polymerization of ceric sulphate on the cathode due to an excessive hydrogen production rate and increase in pH at the cathode surface.
Formation of the polymer can be eliminated by operating in an electrolyte of slightly higher acidity or lower temperature or a combination of both. This polymer can be redissolved from the cathode by exposing it to a mixture of dilute nitric acid and hydrogen peroxide. The polymer can also be dissolved with a mixture of dilute sulphuric acid and hydrogen peroxide.
The significance of operating at high cathode current densities is two fold:
(a) Ceric sulphate exists in the form H2Ce~SO4)3 in solution - ("sulfatoceric acid") which partially dissociates to form HCe(SO4)3- (anion). This negatively charged anion may be repelled from the negatively _ ~ _ V
charged cathode by increasing cathode current density thereby preventing its decomposition.
(b) The higher the cathode current density, the lower is the cathode surface area and the less likely is any form of ceric ion e.g. H2Ce(S04)3 or HCe(S04)3, etc. to make contact with the cathode, thereby reducing ceric ion decomposition.
Ce4+ + le ~ Ce3+
All three factors alone or in combina-tion can have a disastrous effect on current efficiency for ceric ion pro-duction as is evident from Table 2.
~i~66(J 0 The above problems can be avoided if a platinum anode is used instead of the lead dioxide anode used in Table 2. However, the use of platinum at low current densities of 20 mamp/cm2 is too expensive.
Thus the present invention has illustrated that high current efficiencies obtained at high "effective"
current densities and high ceric sulphate concentration when electrolysis is carried out at high anodic and cathodic current densities. It is important to maintain the maximum dissolved cerous ion concentration in the electrolyte for the entire electrolysis.
SUPPLEMENTARY DISCLOSURE
Further work done on the invention described in the principal disclosure has indicated that the process there described is of a broader aspect. According to the further work the present invention is a process for prepa-ring ceric sulphate in solution that comprises electrolysing an at least saturated solution of ceric sulphate at an anodic current density in the range 100 to 400 mamp/cm2, a cathode current density in the range 1,000 to 4,500 mamp/cm2 and with vigorous agitation in the presence of dilute sulphuric acid.
As in the principal disclosure the saturated cerous sulphate may be maintained as such by electrolyzing a suspension of cerous sulphate, or by carrying out the electrolysis of a saturated cerous sulphate solution. A
diaphragm is not used. The electrolysis of a saturated cerous sulphate solution is carried out briefly then the electrolyte is mixed with cerous sulphate crystals to resaturate it with respect to cerous sulphate. Undissolved cerous sulphate crystals are allowed to precipitate. The super-natant liquid is then re-electrolyzed.
The following examples illustrate this development:
Examples Except where indicated otherwise in Table 3 elec-trolysis of a starting electrolyte comprising 25 grams of cerous sulphate pentahydrate, 6.6 ml. of concentrated sulphuric acid diluted to a volume of 100 ml with water to give lM
sulphuric acid was carried out with vigorous agitation of the electrolyte during electrolysis. The results and reaction conditions are set out in Table 1. A diaphragm was not used in the electrolysis.
_ ~ _ 11~
o~ ~ u~
a~ 0 O~ ~ Ir) o~
' ~ a ~ ~ O ~ ~ ~ ~ O ~1 1` 0 C~ ~ ~ ~ 0 ~ ~ u~ ~ ~ u~
~ C~ ~ ~ ~ ~ ~ ~ D ~ U~ ~ `D, ~o ~ I I o ~ o . ~ ~ ~ U~ U~ U~
E~ .
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-,, . . ~ ~ ~
. .K o~ UO
~ ~ goog ggggo gggg ~
C~
. ,.' . ~ ~ S
V
1~
'OU J~ ~o t~ 3r:
/t V
Thus the invention of this supplementary disclosure, like the invention of the principal dlsclosure, has illus-trated that high current efficiencies are obtained at high "effective" current densities and high ceric sulphate con-centration when electrolysis is carried out at high anodic and cathodic current densities. Again it is important to maintain the maximum dissolved cerous ion concentration in the electrolyte for the entire electrolysis. With regard to the present process the generally higher molarities of the final ceric sulphate should be noted.
Further information applicable to the present application is:
Cathode current densities much in excess of 4500 mamp/cm2 (e.g. 6000-8000 mamp/cm2) may result in polymerization of ceric sulphate on the cathode due to an excessive hydrogen production rate and increase in pH at the cathode surface.
Formation of the polymer can be eliminated by operating in an electrolyte of slightly higher acidity or lower temperature or a combination of both. This polymer can be redissolved from the cathode by exposing it to a mixture of dilute nitric acid and hydrogen peroxide. The polymer can also be dissolved with a mixture of dilute sulphuric acid and hydrogen peroxide.
The significance of operating at high cathode current densities is two fold:
(a) Ceric sulphate exists in the form H2Ce~SO4)3 in solution - ("sulfatoceric acid") which partially dissociates to form HCe(SO4)3- (anion). This negatively charged anion may be repelled from the negatively _ ~ _ V
charged cathode by increasing cathode current density thereby preventing its decomposition.
(b) The higher the cathode current density, the lower is the cathode surface area and the less likely is any form of ceric ion e.g. H2Ce(S04)3 or HCe(S04)3, etc. to make contact with the cathode, thereby reducing ceric ion decomposition.
Claims (14)
1. A process for preparing ceric sulphate in solu-tion that comprises electrolyzing cerous sulphate in a form selected from a saturated solution and a suspension at an ano-dic current density, of or greater than 100 mamp/cm2, a cathode current density of or greater than 1000 mamp/cm2 and with vigorous agitation in the presence of 1 to 2 molar sulphuric acid in the absence of a diaphragm.
2. A process as claimed in claim 1 in which the cerous sulphate is electrolyzed as a suspension.
3. A process as claimed in claim 1 in which the cerous sulphate is electrolyzed as a saturated cerous sulphate solution, the electrolyzed solution is mixed with cerous sulphate crystals to resaturate it with respect to cerous sulphate after brief electrolysis, undissolved cerous sulphate crystals are allowed to precipitate and the supernatant, saturated cerous sulphate solution is electrolyzed.
4. A process as claimed in claim 1 in which the ano-dic current density is in the range 100 to 200 mamp/cm2.
5. A process as claimed in claim 1 in which the cathodic current density is in the range 1500 to 2000 mamp/cm2.
6. A process as claimed in claim 1 in which the electrolyte temperature is in the range 25°C to 67°C.
7. A process as claimed in claim 1 in which the anode used in the electrolysis is selected from electroplated lead dioxide, platinum and anodized lead.
CLAIMS SUPPORTED BY SUPPLEMEMTARY DISCLOSURE
CLAIMS SUPPORTED BY SUPPLEMEMTARY DISCLOSURE
8. A process for preparing ceric sulphate in solu-tion that comprises electrolyzing cerous sulphate in a form selected from a saturated solution and a suspension at an ano-dic current density in the range 100 to 400 mamp/cm2, a cathode current density in the range 1000 to 4,500 mamp/cm2 and with vigorous agitation in the presence of 1 to 2 molar sulphuric acid in the absence of a diaphragm.
9. A process as claimed in claim 8 in which the cerous sulphate is electrolyzed as a suspension.
10. A process as claimed in claim 8 in which the cerous sulphate is electrolyzed as a saturated cerous sulphate solution, mixed with cerous sulphate crystals to resaturate it with respect to cerous sulphate after brief electrolysis, allowing undissolved cerous sulphate crystals to precipitate and electrolyzing the supernatant, saturated cerous sulphate.
11. A process as claimed in claim 8 in which the electrolyte temperature is in the range 40°C to 60°C.
12. A process as claimed in claim 8 in which the anode used in the electrolysis is selected from electroplated platinized titanium, platinum and anodized lead.
13. A process as claimed in claim 8 in which the dilute sulphuric acid is one to two molar.
14. A process as claimed in claim 8 in which the cathode used in the electrolysis is made from tungsten.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/321,085 US4683038A (en) | 1980-10-21 | 1981-11-13 | Process for preparing ceric sulphate |
| US321,085 | 1981-11-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1166600A true CA1166600A (en) | 1984-05-01 |
Family
ID=23249119
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000363336A Expired CA1166600A (en) | 1981-11-13 | 1980-10-27 | Process for preparing ceric sulphate |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1166600A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5246553A (en) * | 1992-03-05 | 1993-09-21 | Hydro-Quebec | Tetravalent titanium electrolyte and trivalent titanium reducing agent obtained thereby |
| US5296107A (en) * | 1992-03-04 | 1994-03-22 | Hydro-Quebec | Indirect cerium medicated electrosynthesis |
| US5679235A (en) * | 1992-03-05 | 1997-10-21 | Hydro-Quebec | Titanium and cerium containing acidic electrolyte |
| US5705049A (en) * | 1992-04-07 | 1998-01-06 | Hydro-Quebec | Indirect cerium mediated electrosynthesis |
-
1980
- 1980-10-27 CA CA000363336A patent/CA1166600A/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5296107A (en) * | 1992-03-04 | 1994-03-22 | Hydro-Quebec | Indirect cerium medicated electrosynthesis |
| US5516407A (en) * | 1992-03-04 | 1996-05-14 | Hydro Quebec | Indirect cerium mediated electrosynthesis |
| US5246553A (en) * | 1992-03-05 | 1993-09-21 | Hydro-Quebec | Tetravalent titanium electrolyte and trivalent titanium reducing agent obtained thereby |
| US5409581A (en) * | 1992-03-05 | 1995-04-25 | Hydro-Quebec | Tetravalent titanium electrolyte and trivalent titanium reducing agent obtained thereby |
| US5679235A (en) * | 1992-03-05 | 1997-10-21 | Hydro-Quebec | Titanium and cerium containing acidic electrolyte |
| US5705049A (en) * | 1992-04-07 | 1998-01-06 | Hydro-Quebec | Indirect cerium mediated electrosynthesis |
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