Sciencemadness Discussion Board

Sodum dithionite synthesis

ergoamide - 16-7-2006 at 06:42

Ok first post on here lets see how i go,

I'm after help on a sodium dithionite synth. I checked the rhodium archive and found a zinc dithionate synth, and i was thinkin using simple skils if you placed NaOH in there the NaOH would displace the Zn a a more reavtive metal and Zn would precipitate out (Zn(OH)2 is very soluble is it). Of course thers the formate procedure but i don't have access to formates. The i read on the wikipedia that sodium bisulphite can be reduced by Zn to sodium dithionate directly.

I can't myself see any problems with the reaction as Zn reduces the free acid to the dithionate, the hydrogen isn't involved in it so i figure neither will the sodium. So if it works which i'm prettys ure it should then all you would really have to do is make a sodium bisulphite solution then add a slight molar excess of Zn powder and wait until most fo the Zn powder has been consumed and filter off the Zn(OH)2.

So what are your opinions, what tweaks should i make to make this work better (assuming it does work).

EbC: title spelling

[Edited on 19-7-2006 by chemoleo]

solo - 16-7-2006 at 08:07

Reference Information


A method for preparing analytically pure sodium dithionite. Dithionite quality and observed nitrogenase-specific activities
Charles E. McKenna, William G. Gutheil and Wei Song
Biochimica et Biophysica Acta (BBA) - General Subjects, Volume 1075, Issue 1, 2 September 1991, Pages 109-117

http://rapidshare.de/files/26079764/A_method_for_preparing_a...

Abstract
Sodium dithionite (NazSzO 4) is widely used as a reductant in biochemical studies, but has not been available in its pure form. A convenient, detailed procedure is given for the recrystallization of commercial dithionite from 0.1 M NaOH-methanol under anaerobic conditions. Twice-recrystallized dithionite had a purity of 99 _+ 1% by IN spectroscopy (A3I s) and elemental analysis. The influence of dithionite quality on the apparent reduction activities of the nitrogenase components (Avl and Av2) from Ay.otobacter vinelandii was investigated.




[Edited on 17-7-2006 by solo]

Attachment: A method for preparing analytically pure sodium dithionite.pdf (676kB)
This file has been downloaded 5322 times

ergoamide - 16-7-2006 at 22:34

oh dam the file wont let me download ti it keeps comin up with filel cannot be written to cache. crap arse computer.

acetate - 19-7-2006 at 07:36

Copy from publication:

Angewandte Chemie International Edition in English
Volume 18, Issue 4 , Pages 313 - 314
Quote:

A solution of SOz (212 g) in methanol (636 g) and a solution
of sodium formate (120g) in water (106g) are simultaneously
added (50 % of each solution in 15 min and the rest within
7.5 min) to a suspension of sodium formate (1 20 g), NaOH(solid)
(9Og), water (382g), and methanol (402g) in a 2-1 glass
flask fitted with a stirrer and two entry tubes; the temperature
is kept at 67°C during the addition. After cooling to 60°C,
the solid material is filtered off, washed with methanol, and
dried. In this way, 211 g of a crystalline product is obtained
which consists of Na2S2O5.NaOOCH (94.5 %), Na2S2O4
(2.3 %), Na2SO3 (3.0 %), and Na2S2O3 (0.2 %); the yield of
Na2S205.NaOOCH is 46.7 % based on SO2.



... I have "old" preparation of Na2S2O4 from HCOOH, HCOONa and Na2S2O5 in ethanol/H2O but I dont know how it is good ... if you want I will must translate this preparation ...

Attachment: Na2S2O4.pdf (255kB)
This file has been downloaded 1181 times

ergoamide - 20-7-2006 at 22:54

I was more wondering if anyone had some conformation about using a bisulfite solution but no worries i know that it works now they sometimes use it industrially. Now all i need to know is an efficient way of separating it form zinc hydroxide.

neutrino - 21-7-2006 at 06:42

Zinc hydroxide is insoluble in water. Just filter or decant the mixture.