Carbon Dioxide → Dichromate ion

HRID 1655156Notes

Reaction equation

C(=O)=O.[Cr:4]([O-:8])([O-:7])(=[O:6])=[O:5].[Na+:9].[Na+].[C:11](=[O:14])([OH:13])[OH:12]>>[Cr:4]([O:8][Cr:4]([O-:7])(=[O:6])=[O:5])([O-:7])(=[O:6])=[O:5].[C:11](=[O:12])([O-:14])[OH:13].[Na+:9]

Participants

Reactant 3

HCID 280Carbon Dioxide2×

HCID 767Carbonic Acid

HCID 24488Sodium Chromate

Product 2

HCID 24503Dichromate ion

HCID 516892Sodium Bicarbonate

Procedure

For acidification with carbon dioxide, the sodium monochromate solution is adjusted to a concentration of from 750 to 1,000 g/l Na2CrO4 and is saturated with carbonic acid in autoclaves by introduction of carbon dioxide under a pressure of from 0.5 to 1.5 MPa (5 to 15 bar). 75 to 95% conversion of monochromate ions into dichromate ions is obtained with precipitation of sodium hydrogen carbonate. The remaining conversion to 100% can be obtained by introduction of carbon dioxide in another stage after concentration to 1,300 g/l Na2CrO4 (already formed Na2CrO7.2H2O expressed in Na2CrO4 equivalents). On an industrial scale, however, this final conversion step is very complicated. The final conversion step may also be carried out with sulfuric acid or by electrolysis.

Sources & evidence

ORD record: ord-b3c5a56be3c7408b8f31fe27749cb05c
Source dataset: uspto-grants-1993_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05250274

Reaction notes

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