Ok, I guess you're talking about Spur developers, Adotech, Silvermax etc. I don't know if anyone synthesising HQMS for personal use have been able to create effective substitutes for these developers. Other than these, is there anything from the distant or not so distant past in the public domain?
The Wheatcroft patent has been discussed here several times, and IIRC was initially brought up by PE.
Although it can be shown theoretically that the conversion does not take place, it can also be verified experimentally: prepare a batch of developer per the patent and a second batch, where the H2O2 is added to the sulfite in absence of HQ and the rest of the developer mixed. Run parallel sensitometric tests. Alternatively, the free HQ can be extracted with ethyl acetate and quantified.
Oxygen can be used and the reaction proceeds as expected, but again, it is pH dependent and produces hydroxide, so either a strong buffer system has to be used or pH correction has to be applied continuously. This still means the liberated Na+ has to be bound up as some salt, the acetate or borate being the least troublesome. I thought I can be clever and use SO2 gas to neutralize the NaOH back to sulfite but it cannot work in a batch process, and it becomes a frustrating juggling act to do it continuously.
Since I have - I believe - already mentioned this at least once, you can consider this a formula in the public domain :-D
@lamerko , I have to agree with Rudi that the procedure, as outlined by the AI, is broadly unclear, and will not result in any meaningful yield of the sulfonate.
Glacial acetic acid is a pretty good polar, protic solvent and is used in substitutions reactions, most notably in aromatic nitrations, since it tolerates nitric acid and forms the active nitration species in that case. The solubility of HQ in GAA is not mentioned in the CRC databooks, but I was able to quickly find a reference(https://pubs.acs.org/doi/pdf/10.1021/ja01333a057), where it is stated that 60g dissolved in 250g of solvent on heating, so that may be a reason to use it. However, the solubility of HQ in water at room temperature is about 70g/L, so not orders of magnitude difference. HQ-sulfonic acid is very water soluble, in fact it hydrolyzes on standing as an aqueous solution, so it is only prepared to then be converted to a salt (sodium, potassium, calcium are the most common).
I think the silicon mind was thinking about nitration and not sulfonation. Nitrations are usually carried out at low temperatures and slowly to prevent side products and increase yield. Sulfonations are much harder to effect in practice. For example, to prepare benzenesulfonic acid, benzene must be treated at boiling point with oleum, which is sulfuric acid with added sulfur trioxide - basically the anhydride of H2SO4. HQ is a bit easier, the two hydroxyl groups activate the ring quite well, so regular concentrated acid will do the trick. In both cases, the reason for the high concentration of H2SO4 is to act as a dehydrating agent - the sulfonation is an equilibrium reaction and the resulting HQ-sulfonic acid can hydrolyze back to HQ and sulfuric acid in the presence of water, so an excess of H2SO4 is used to sequester the water (or the reaction is carried out under vacuum to remove water as it forms). This is well known and the earliest preparations of HQ sulfonates (Seyda, 1880s), outline the procedure in sufficient detail. Even the 10-20% water suggested would represent a stoichiometric excess to the amount of HQ that can be dissolved, even at reflux. At room temp or near the ice point, you will end up with an acidic slurry of HQ, water and acid, the activation energy is much higher. There are only two (reasonable, non-esoteric) methods to obtain HQMS at room temperature, either by reductive sulfonation of the quinone with tight pH control, or by anodic sulfonation at a platinum or carbon electrode, with a bit looser pH dependence.
The two above points make preparation of HQ-sulfonates difficult, because both the free acid and its salts are very water soluble. You can use the common ion effect to precipitate them out of solution (prepare a concentrated solution, then add sulfate salts and sulfuric acid), but the usual recrystallization yields are in the 10-20% range. Another unfortunate complication is that sulfates are almost always produced as a byproduct and have almost identical physical properties to the sulfonates, regarding solubility. Weissberger, et al, to prepare about 100g of HQMS-Na, use 7 liters (2 gal) of boiling hot methanol, to extract the salt from a reaction mix. Only the calcium salt (also known as calcium dobesilate) has reasonable solubility in simple alcohols, and can be separated out more easily (but converting it back to the more useful K or Na salt is a pain).
The sulfonation of HQ, without further purification is described in the attached patent. I have followed it successfully at molar scales. For b/w developers, the stoichiometric sulfate present can be accounted for and does not present a problem. For color work, the product has to be purified by extraction.
I'm not too sure about the purity of my chemicals. Traders give specific numbers - purity and what impurities they contain, but apparently a lot of chemicals arrive in sacks and larger cuts of unclear quality. Some of them sell them simply in bags, others in not very good quality containers. Hygroscopic chemicals have probably absorbed a lot of moisture. Surprisingly though, what I've mixed so far is probably very close to the expected results.
For Citrazinic acid - until recently there was a chain store in the UK - Silverprint, which unfortunately recently went bankrupt. They had a crude chemicals section - they offered Citrazinic acid at a very good price. £23.00 - 100g including VAT. It is not known with what purity...
I currently have ATMP and DTPA-5Na, but I will test without them to see how long they would last.
Weissberger, et al, to prepare about 100g of HQMS-Na, use 7 liters (2 gal) of boiling hot methanol, to extract the salt from a reaction mix. Only the calcium salt (also known as calcium dobesilate) has reasonable solubility in simple alcohols, and can be separated out more easily (but converting it back to the more useful K or Na salt is a pain).
Here are few samples what I got from Velvia 100 using homebrew HQMS-K and CZA. Everything else is as in the patent except the order of preparation of buffer solutions, the absence of any chelating agents and some occasional base substitutions like K<->Na. And there are no accelerators in the color developer. I'm going to try ethylenediamine but it's still on the way. The images are clearly underdeveloped, so I'm going to do some troubleshooting.
Hi Mantis
This patented product has been produced in my country and has been used to develop tens of thousands of rolls of reversal film.
We also used Fujifilm e6 control strips,shows diviation within ± 0.02D.
But because we produce according to this patent without modification at all (and we have a professional laboratory), we use the purest chemical raw materials, and use chemical analysis for testing, so the quality of the output is very good
But you may not have this condition, so you can consider buying the e6 chemical that Kodak is about to re produce.Or because you may need to use substitutes for many of the ingredients or the purity is insufficient, so you must also check the pH of the chemical
Yes, they have been producing the E-6 chemical kit with this patented formula for over a year now, and it's exceptionally high-quality.Do you mean specifically the year 1999 patent mentioned in topic? Because it seems like at some point (according to 1993 patent) Kodak's first developer had slightly more developing agents and lower pH. I also checked Fuji patent and it asks for a double amount of Dimezone-S.
Yes the 1999 one is the only correct one(or the only one our lab has proved it is totally correct)Do you mean specifically the year 1999 patent mentioned in topic? Because it seems like at some point (according to 1993 patent) Kodak's first developer had slightly more developing agents and lower pH. I also checked Fuji patent and it asks for a double amount of Dimezon
Yes, they have been producing the E-6 chemical kit with this patented formula for over a year now, and it's exceptionally high-quality.
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