Sciencemadness Discussion Board - Info on sodium dithionite please

Info on sodium dithionite please

nitrone - 9-11-2007 at 00:06

Hi

I know very little about sodium dithionite except that it is a strong reducing agent. I have aquired some but before I use I was wondering if someone could please give me some more info on the reduction conditions, condions to avoid and so on. I know it reduces aldehydes and ketones to alcohols and nitro groups to amines, here's a reduction procedure for limunol:

PART 2. Add 1.0 mL of 3 M sodium hydroxide solution to the solution from Part 1. Stir
with a rod, and to the resulting deep brown-red solution add 0.6 g of fresh sodium dithionite.
Wash the solid down the sides of the test tube with a little water. Heat to the boiling point, stir,
and keep the mixture hot for 5 minutes, during which time some of the reduction product may
separate. Then add 0.4 mL of acetic acid, cool the tube in a beaker of cold water, and stir.
This solution will be used as is; there is no reason to collect the solid luminol product.

If I wanted t reduce 4-nitrochlorobenzene, how would the chlorine be affected? Does the use of NaOH vs sodium carbonate change the reduction capabilities? Are the reduction conditions similar for ketone reductions. I have searched for more information on google but can't seem to find any general information about sodium dithionite and it's reactions.

Sauron - 9-11-2007 at 20:20

When you need practical information on the use of a specific reagent, you have a number of options for sources of such information.

Here are some of them.

1. UTFSE. Do a forum search on sodium dithionite and read what has been written about it before. There are 16 threads that discuss or mention sodium dithionite (including this one.).

2. www.orgsyn.org. Select the non plugin keyword search option. Search on sodium dithionite. You will find two hits, one of them merely references a paper but the other one uses dithionite in a reduction of vicinal carbonyls to 1,2-hydroxyls which are then alkylated.

That prep is attached.

3. Google Yeah I know it's like slogging through the Dead Marshes with Frodo, Sam and Gollum. But sometimes you find something useful.

4, If you have access to references, go download Paquette's ebook from the New Books (Organic Chemistry) thread. If you do not have access to References, ask a moderator for the PW. PS I just looked at Paquette's info on Sodium dithionite, and it is extensive and detailed with thirty references to very current journals and books. I can't copy it but I will try printing it and scanning, if succesful I will post it here.

5. Go to amazon.com or allbris and start buying used copies of Feiser's Reagents for Organic Synthesis series.

6. Use the Advanced Search option on the ACS Publications website and search JACS and JOC and I&EC (or all journals) for sodium dithionite. Chem.Rev would be particularly valuable if there is a review on dithionite reductions. (I just did this, but there are no Chemical Review articles specifically on sodium dithionite or hydrosulfite.)

7. Merck Index may have literature references on the use of this reagent. As it happens Merck Index 12th Edition does not, but this is still good general procedure.

This why we have the primary, secondary and tertiary chemical literature, and the luxury of the Internet. Believe me, if you were old enough to have lived when this had to be done ,anually in a library you would appreciate what a luxury the Internet truly is!

So USE it. Your questions cannot be answered properly in a forum post.

As an afterword: in the older lit. this compound is often called sodium hydrosulfite. This is how it is listed in Merck and how it is sold by Acros. Also, do not confuse sodium dithionite Na2S2O4 with sodium dithionate Na2S2O6.

[Edited on 10-11-2007 by Sauron]

Attachment: v80p0227.pdf (153kB)
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Sauron - 9-11-2007 at 21:46

Here is an eight page pdf I just made from printout of Leo Paquette's section on sodium dithionite, amounting to a mini-review. I found I could not use the Print to PDF function so I had to scan the hardcopy in Acrobat.

[Edited on 10-11-2007 by Sauron]

Attachment: dithionite.pdf (479kB)
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Magpie - 9-11-2007 at 22:39

That is interesting information on the usefulness of sodium dithionite. It is a surprisingly versatile reducing agent. I wonder if sodium thiosulfate (of which I have much more) might be equally useful.

I guess what I'm saying is does anyone know how these two salts compare in reducing power?

Sauron - 9-11-2007 at 22:57

Anyone who ever did any darkroom work will confirm that sodium thiosulfate is a reducing agent ("hypo") but I will have a look at Paquette etc to see how it may be employed in organic chemistry.

According to Paquette, thiosulfate is useful but does not have the power or scope of dithionite. Three page pdf extract attached. Print to PDF now working (I guess it took a reboot).

Nicodem recently pointed out that dosium dithionite, premixed with sodium carbonate, is sold otc as a laundry brightener or whitener. I wonder what the brand name might be?

[Edited on 10-11-2007 by Sauron]

Attachment: thiosulfate.pdf (29kB)
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nitrone - 10-11-2007 at 02:32

Thank you for the information Sauron, I did UTFSE thats why I asked if the use of carbonate instead of hydroxide would make a differance to the reaction, or if halogenated nitro,carbonyl compounds etc could also be reduced using such alkaline conditions . Again I appreciate the time you took and found the info and guides you supplied invaluable.

Magpie - 10-11-2007 at 10:06

Thanks for the references and comparison, Sauron.

Sears also sells a water softener cleaning compound made of sodium dithionite mixed with sodium bisulfite. I don't know the relative proportions. It was $13/20 oz when I saw it a year or two ago. I too would like to know the brand of laundry whitener that has sodium dithionite. It would probably be a lot cheaper.

[Edited on by Magpie]

Eclectic - 10-11-2007 at 10:10

Tractor Supply in the US sells sodium dithionite as "Rust Out"

[Edited on 11-10-2007 by Eclectic]

Magpie - 10-11-2007 at 10:33

From Eclectic:

Quote:

Tractor Supply in the US sells sodium dithionite as "Rust Out"

Searching on the internet I find:

http://www.bigbrandwater.com/prwh.html

They have both the Rust-Out and the laundry whitener. Probably the same formula, just different label.

pantone159 - 7-12-2007 at 17:34

I notice that the laundry whitener mentions is it scented, as well as listing more additives. From the 'Details' tab:
http://www.bigbrandwater.com/laundrywhite.html

Quote:

Technical Information

White powder with appealing scent. (Do not use with bleach or peroxide.)

Formulation

Sodium Hydrosulfite – CAS# 7775-14-67 Sodium Metabisulfate – CAS# 7681-57-4 Optical Whiteners – N/A Other Laundry Additives – N/A

But, for the rust-out:
http://www.bigbrandwater.com/rustout.html

Quote:

Technical Information

Pro-Rust Out is a white powdered mixture with a sulfur odor. It is a reducing agent that chemically changes rust into a clear, soluble state that easily rinses away. [This change is: Fe3 to Fe2 (Ferric to Ferrous).]

Formulation

Sodium Hydrosulfite – CAS# 7775-14-6 Sodium Metabisulfate – CAS# 7681-57-4 Other Additives – N/A

So I'd pick the rust-out as being more pure. Also note that MetabisulFITE is mispelled in the product information, the CAS refers to the metabisulfite, I don't think there is such a thing as metabisulfate.

EDIT - Also the manufacturer's page, and an MSDS for the rustout:
http://www.proproducts.com/products/cleaning/rustout.htm
http://www.waterfiltersonline.com/manuals/PRORustOut-Feb98.d...

[Edited on 7-12-2007 by pantone159]

Magpie - 7-12-2007 at 19:53

Yes, I agree that the Rust-Out would be the better choice.

Usually when a chemist uses Na dithionite it is for a reduction. Likewise Na metabisulfite. So I'm thinking that reductions that call for dithionite could most likely be done with Rust-Out as is. It might just be necessary to use a little more to compensate for the dilution with metabisulfite.

I wonder if there is some relatively simple way of isolating just the Na dithionite? This is a fairly expensive reagent, IIRC. It would be nice to have a cheap OTC source.

Eclectic - 7-12-2007 at 20:19

It's made by zinc or electrolytic reduction of the metabisulfite.

Jamjar - 7-12-2007 at 21:25

Dithionite OR hydrosulfite OR hydrosulphite

Reducing agent for indigo and vat dyeing.
Maiwa: Craft Supply - Natural Dyes - Indigo
Jacquard Sodium Hydrosulfite

smuv - 7-12-2007 at 21:52

IRON OUT AUTOMATIC TOILET BOWL CLEANER which is apparently sold at walmart (listed on their msds website) lists only sodium hydrosulfite in its active ingredients.

Magpie - 7-12-2007 at 23:10

Quote:

IRON OUT AUTOMATIC TOILET BOWL CLEANER which is apparently sold at walmart

Whoooeee! It just doesn't get any more OTC than this! Housewives and chemists unite!

chloric1 - 21-6-2008 at 08:51

Been researching this myself. Thanks Jamjar for the link. I was going to deal with jacquard for dyeing anyways. Interesting hobby especially since al my tie-dyes have holes in them

So I went to wal-mart to get some fruit of the loom t-shirts, RIT, rubber bands, and disposla latex gloves.

I read that sodium hydrosulfite is insoluble in alcohol, and it salted out by NaCl and CaCl2. Other salts work too but I cannot recall. So gently mix your product in minimal water at no warmer than 20 degrees C and add a solution of 30 grams of rock salt in 100 grams of distilled water and put in the freezer. Or add 95% alcohol or acetone. Acetone should remove metabisulfite also.

YT2095 - 22-6-2008 at 00:16

here`s one of the most recent thread related to it: http://www.sciencemadness.org/talk/viewthread.php?tid=10433&...

Vogelzang - 2-7-2008 at 14:46

Look at this reference and these patents. http://www.pat2pdf.org

Aust. J. Chem. 32, 205 1966 P. M. Pojer.
The conditions are: 30 mmol ketone + 30 mmol amine in 70 ml DMF, 110°C, + 120 mmol NaHCO3, + Na2S2O4 + 30 ml H2O, 30 min 110 °C, + 300 ml H2O, ether extraction. The yields are around 70%.

US 5350425 Method of reducing vat dyes and the process of dyeing fabrics therein
column 1 lines 49+
Typically, sodium dithionite has been employed to reduce the dyes to
their leuco form, as is shown U.S. Pat. No. 3,798,172. Sodium dithionite
decomposes rapidly in the presence or absence of air; therefore, large, excess
quantities of this compound are used to reduce all of the dye and to maintain
the dye in is soluble leuco form. Regrettably, the use of sodium dithionite
raises ecological concerns.

US 1810663 Stripper for fabrics
dithionites

US 1975443 Production of sodium hyposulphite and zinc compounds
Zn and SO2 --> Zn hyposulfite

US 2637687 Electrodeposition of nickel

US 3468623 DRY STABILIZED DITHIONITE COMPOSITIONS

US 3523069 PROCESS FOR THE PRODUCTION OF DITHIONITES
electrolytic

US 3709779 BLEACHING OF MECHANICAL PULPS WITH HYDROSULFITE IN THE PRESENCE OF AN ALKALI METAL SILICATE

US 3804944 SODIUM DITHIONITE SOLUTION STABLIZATION

US 3819807 STABILIZED SODIUM DITHIONITE COMPOSITIONS

US 3923960 Compositions containing dithionites
stability