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Preparing the Marquis Reagent

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bagera tomorrow

bagera tomorrow

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This seems like the most appropriate forum so here goes. I want to make my own Marquis Reagent but I'm having a lot of trouble finding any information on it. All I've been able to find is that it's 9 parts H2SO4 and 1 part H2CO and some people add methanol to help it react slower. Other than that I have no idea if there's anything in particular I need to do to prepare it. I can't find any sort of procedure anywhere. Has anyone here ever prepared it?
 
Add the conc. H2SO4 to the formaldehyde solution, not the other way around. Acid splashes aren't fun. (with the possible exception of the lysergic variety)
 
and just to state the obvious, always work in suitable lab attire. Don't mess with conc. h2so4 in boardshorts and no shirt ;)

Work in small volumes too, you only need one drop per test and Marquis reagent can 'go off' after a few months, dont bother mixing more than you'll use.

also, to test it (just to make sure you did it right) you can use various thing around the home. I think wikipedia(for marquis reagent) has a good list of what substance turns which colour
 
I certainly plan on doing it in a hood under proper lab conditions as everyone always should. conc. h2so4 is no joke! I'm just going to prepare maybe a few milliliters of the stuff at most. I don't really want to play with lots of formaldehyde.
 
The golden rule of never adding water (formalin) to acid isn't applicable for Marquis.

After many years spent perfecting the preparation (avoiding early polymerisation, low shelf life etc) I found the best prep (for quantities of 1L or more) involved using a pressure equalizing addition funnel, with a nozzle attached that penetrates the surface of the acid. With stirring, formalin is dripped into the mixture, at a rate such that the temperature remains below 35 deg C. The worst problem results when Formaldehyde is vapourised. Using a take off from the top of the funnel to a bucket of water prevents any gas from escaping.

If your formaldehyde is methanol free, then a few drops are added to further inhibit polymerisation.
 
phase dancer, can you be more clear about the ratio of methanol to formaldehyde? I certainly don't plan on making more than ~5 mls of the stuff.
 
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