I would like to extend my interest into primaries and particularly organic azides to triazidotrinitrobenzene (not to be mistaken with triamino trinitrobenzene, sometimes improperly shortened to TATNB iso TATB). It is prepared from 1,3,5 trichloro-2,4,6 trinitro benzene and NaN3. I can access to 1,3,5 trichloro benzene (although it is pretty expensive) and NaN3. However, could someone on this forum having access to Urbanski I (I only own volume III) post the nitration process to make 1,3,5 trichloro-2,4,6 trinitro benzene from 1,3,5 trichloro benzene ?

All other information about TATNB properties, in particular its initiating power, is welcome.

I remember COPAE has a little info on it, I'll have a look in a few minutes and post anything useful.
Nitrating TCB is going to be HARD I would think. I don't have access to Urbanski, but I'm sure someone will help you out there.
One thing I do remember from COPAE is that a elevated temperatures it loses nitrogen. They showed it going to hexanitrosobenzene, but I think the trifuroxan would be more likely, considering that furoxans are produced by heating 1-azido-2-nitrobenzenes... it's an old book, maybe they were not very familiar with furoxans back then, I don't know.
Anyway, I'll look it up now and post some things...

Can you get cyanuric trichloride? Or isocyanogen tetrachloride? More possibilities there! I wish I could get my hands on them...

Edit: from COPAE:

"The nitration, as described by Turek, is carried out by dissolving the material [TCB] in warm 32% oleum, adding strong nitric acid, and heating at 140-150*C until no more trinitrotrichlorobenzene, mp 187*C, precipitates out."

Hardly gentle conditions...

Then an acetone solution of TNTCB, or the dry powder, is added to a solution of sodium azide in moist alcohol with good stirring. The precipitate can be purified by recrystalisation from chloroform, mp 131*C with decomposition. It is readily soluble in acetone and sparingly so in alcohol, not in water. It's not hygroscopic, is stable in water, is non-corrosive, not appreciably volatile at 50*C, the surface darkens in light. 0.665% decomposes in 3 years at 20*C, 2.43% in 1 year at 35*C, 0.65% in 10 days at 50*C, 100% in 14 hours at 100*C. The product (whatever it is) has mp 159*C, is stable, not primary, not hygroscopic, comparably to tetryl in explosive properties.
TATNB has a drop test value of 30cm - not sure what weight was used, though. Less sensitive to mechanical stimuli than is mercury fulminate.
TNT requires 0.02g of the material to detonate when compressed under 500kg/cm2, tetryl, 0.01g. It can be dead-pressed, although it doesn't state the loading pressure at which this occurs.
In the Trauzl test, it gives 90% the expansion of PETN.

The nitration set forth in Urbanski I is an industrial proceedure. You'd have better luck with the proceedure from COPAE.

In the section of hexanitrosobenzene, it mentions that it was initially thought to be a benzotrifuroxane structure, but that was not the final settlement. The NMR spectrum pointed to benzotrifuroxane structure. It was classified as a true nitroso back when it was first made. It was said to be more probable. Now, many believe that it is indeed a benzotrifuroxane.

Here it is anyway:
The reactor is charged with 980 kg of 30% oleum to which 100 kg of solid
trichlorobenzene is added during the course of one hour. The whole is heated to 100°C for another hour and kept at this temperature for 2-3 hr longer with constant stirring. Towards the end of this operation sulphonation takes place. The reaction may be considered complete when a sample of the mixture taken fromthe nitrator dissolves completely in water.

After cooling the reactor contents to 50°C 300 kg of 99% nitric acid are added during about 4 hr. While this is being done the temperature rises to 100°C. After all the nitric acid has been added, the mixture is stirred for another 10-14 hr, then during the course of a further 8 hr the temperature is gradually raised to 140-145°C. As too rapid a rise of temperature would involve the risk of decomposition, if this occurs the nitrator contents should be drained off into a safety tank. After a temperature of 140-145°C has been attained, the mixture in the nitrator is stirred at this temperature for further 45 hr. At this stage of the process the product of the reaction crystallizes. Then the nitrator contents are cooled down to 20°C and transferred by compressed air to the filter. The filtered product is transferred to a washing tank, where it is washed by mixing with cold water, followed by decantation, several times until free from acid (Congo paper test).

The spent acid contains 13% of HNO3 and H2SO4 + SO3 equivalent to 90% H2SO4. The washed, acid-free product is filtered off on a vacuum filter and dried under reduced pressure at 100°C. In this way 125 kg of the product melting at 189-190°C are obtained, which corresponds to 72% of the theoretical yield.

Dichlorobenzene is very easily available near me. It is sold as "para" mothballs. Would it be possible to make Diazido trinitrobenzene?

p-DCB would not be a good starting point. You'd probably end up with a product that was reactive and unstable due to the relative positions of the substituents, assuming you went for trinitro and replaced both chlorines.
Hmmm... I must check the price of dinitrophenylhydrazine...

Paradichlorobenzene has been nitrated to dinitrodichlorobenzene ,
which is useful as an explosive itself , but more useful for its
ability to form a eutectic melt with picric acid , similarly as
is true for picric acid eutectics with mononitronaphthalene or DDNP .
The potential for tertiary eutectics would seem possible also ,
but I do not know of any having been reported .

Anyway , the dinitrodichlorobenzene from "para" may be a useful
intermediate for synthesis of other explosives . I have wondered
if it may not be a candidate for diazotization using sodium nitrite ,
and perhaps also of interest in its potential reactions with many other
materials where the chlorine could be replaced by more energetic
substituents .

US1366048 gives the details for a simple method of synthesis
GB126685 describes a sodium nitrate / sulfuric acid nitration
for monochlorobenzene to the dinitro derivative ,
which is likely applicable also to dichlorobenzene ,
and would simplify the process further .

Nitrations of such chlorobenzenes produce extremely disagreeable
and toxic fumes having effects similar to "tear gas" , or "mace" ,
so good ventilation and protection is essential when working with
such materials .

Thank you all for the information provided.

Well, given the high price of 1,3,5 trichloro benzene, the burden of its nitration (don't feel like watching hot sulfonitric acid for an entire night...) and its inherent toxicity hazards, I may opt for cyanuric triazide, whose preparation from cheap cyanuric chloride cannot be easier... On top of that, its ability to casting sounds interesting for a primary, although more info in needed as regards as how to avoid formation of big sensitive crystals at cooling.