Sciencemadness Discussion Board

Alternatives to dichromate for oxidation of TNT to TNB

Chisholm - 7-4-2017 at 08:01

The procedure in CoPaE for oxidation of TNT to TNBzOOH with dichromate, followed by decarboxylation with heat, is very well described.

However, disposal of the heavy metal waste is not.

Are there alternative oxidizing agents? I know that digesting with additional nitric acid at higher temperatures can effect an oxidation, but it also tends to produce N2O4 and oxalic acid if temperature control is even slightly hindered.

Potassium chlorate is too indiscriminate.

Can permanganate be used as a substitute, either in H2SO4 solution or as an acidic aqueous solution with a suspension of molten TNT?

JJay - 7-4-2017 at 08:24

Permanganate is usually better at those sorts of oxidations than dichromate.

PHILOU Zrealone - 7-4-2017 at 16:35

Cl2/NaOH (thus bleach) should be able to drive you from TNT to
--> chloromethyl-TNB (trinitrobenzyl chloride),
--> dichloromethyl-TNB
--> and trichloromethyl-TNB...

aside with hydrolysis and side chain oxydation products because those benzylic halides are quite reactive (activation by the aromatic ring but also by the EWG onto the aromatic ring --> lachrymators vapours/fog/dust...maybe chemical weapon like.
--> hydroxymethyl-TNB (alfa-hydroxy-TNT);
--> trinitrobenzaldehyde (discrete form of dihydroxymethyl-TNB);
--> trihydroxymethyl-TNB (discrete form of trinitrobenzoic acid)

Possible decarboxylation product TNB (from trinitrobenzoic acid) and chloroform elimination by reaction with water and base
TNB-CCl3 + OH(-) --> TNB-OH (= TNP) + CCl3(-)

JJay - 8-4-2017 at 10:45

Also, you can reduce hexavalent chromium compounds with an acid and isopropyl alcohol or with sodium bisulfite. That leaves you with trivalent chromium compounds... trivalent chromium is actually an essential trace mineral for animals. It's not really good for the environment, and if soil levels get too high it makes land unsuitable for farming, but sanitation and water treatment services can deal with quantities that amateurs would be likely to produce.

unionised - 8-4-2017 at 10:51

Quote: Originally posted by PHILOU Zrealone  
Cl2/NaOH (thus bleach) should be able to drive you from TNT to
--> chloromethyl-TNB (trinitrobenzyl chloride),
--> dichloromethyl-TNB
--> and trichloromethyl-TNB...

aside with hydrolysis and side chain oxydation products because those benzylic halides are quite reactive (activation by the aromatic ring but also by the EWG onto the aromatic ring --> lachrymators vapours/fog/dust...maybe chemical weapon like.
--> hydroxymethyl-TNB (alfa-hydroxy-TNT);
--> trinitrobenzaldehyde (discrete form of dihydroxymethyl-TNB);
--> trihydroxymethyl-TNB (discrete form of trinitrobenzoic acid)

Possible decarboxylation product TNB (from trinitrobenzoic acid) and chloroform elimination by reaction with water and base
TNB-CCl3 + OH(-) --> TNB-OH (= TNP) + CCl3(-)


I'm fairly sure that TNT isn't stable in alkaline conditions. What you have proposed is rather close to the synthesis of chloropicrin.
https://en.wikipedia.org/wiki/Chloropicrin

Alpha trichlorination under acid conditions might work, but I'm not sure what would happen during the hydrolysis.

Chisholm - 8-4-2017 at 11:59

I'm pretty sure that bleach oxidizes TNT to hexanitrostilbene.

PHILOU Zrealone - 8-4-2017 at 16:21

Quote: Originally posted by Chisholm  
I'm pretty sure that bleach oxidizes TNT to hexanitrostilbene.

Plausible that HNS is formed transitory from TNBenzaldehyde and TNT in basic media (what bleach is)...but later the double link between the two aromatic rings will be oxydized and deliver then TNB.