Draco_Aster Posted April 25, 2006 Posted April 25, 2006 I have decided to synth some boric acid. After a fair bit of searching I came across this: (Borax)--------------------------------------------------(Boric Acid)Na2B4O7 + H2SO4 + (5)H2O ======> Na2SO4 + (4) H3BO3 Unfortunately that was the only info I found and I dont know how It can be extracted. It is soluble in water so maybe it can be precipitated out of the spent acid mix....If Na2SO4 wasnt soluble aswell Has anybody here made it? Any suggestions? Help would be much appreciated.
Swany Posted April 25, 2006 Posted April 25, 2006 At 0C, Na2SO4's soluability is roughly 5g/100ml H2O. It rises nearly 10 fold in a mere 35 degrees to 50g/100ml. May find that handy... Boric acid's soluability is quite low, I think hovering from 4-6g/100ml or so. So, you could heat evaporate until you see crystals form, then cool to 35-40 and filter.
Rogue Chemist Posted April 25, 2006 Posted April 25, 2006 Thats why you react with HCl instead, you end up with salt with a solubility in the vicinity of 30g/100ml. It works, I did it testtube scale once after reading it in the golden book. Not that I need it with my 5lbs of it from the pottery store .
Draco_Aster Posted April 25, 2006 Author Posted April 25, 2006 Thanks for the help guys. I will do the HCl method on a small scale as H2SO4 is quite expensive for me. So I can basically use the same method in making BaCl2 except I need to evaporate it because of its solubility.
Mumbles Posted April 25, 2006 Posted April 25, 2006 Boric Acid Author: Bastard Preparation: 46.3 g of borax is dissolved in the smallest possible amount of water, and 20.3 ml of concentrated hydrochloric acid is added to the solution. The mixture is cooled down and the precipitated acid filtered out. Use a frit for the filtration, paper will be corroded. The crude acid is dissolved in the smallest possible amount of hot water, then the solution is cooled down in an ice bath and the precipitated acid filtered out. Wash the product with ethanol and dry on a Petri dish (not paper!) Yield: 13.2 g (44% theory).Properties: White translucent leaflets, only slightly soluble in cold water. Strong heating results in dehydration, yielding boron(III) oxide, or hydrates thereof. The acid is caustic when wet.
Frozentech Posted April 25, 2006 Posted April 25, 2006 Boric acid's soluability is quite low, I think hovering from 4-6g/100ml or so.Right on the money. I made up a solution for wetting Al containing comps, and decided to just put the Boric Acid into my solvent. It saturates at 6 gm / 100 ml in warm water ( sorry no exact temp, but under 140 F ). Then I use that solution 70% with 30% Ethyl Alcohol and not worry about adding any other Boric Acid to Al / Nitrate comps.
Givat Posted April 25, 2006 Posted April 25, 2006 Is theres a way to ger borax from boric acid? (opposite reaction)
Swany Posted April 25, 2006 Posted April 25, 2006 Neutralising a boric acid solution with NaOH would be the first thing that comes to mind.
Douchermann Posted April 25, 2006 Posted April 25, 2006 Yeah, that would probably work. You could also use a carbonate or bicarbonate, especially if you don't have any litmus paper to gauge when its done.
FrankRizzo Posted April 25, 2006 Posted April 25, 2006 I have decided to synth some boric acid. After a fair bit of searching I came across this: (Borax)--------------------------------------------------(Boric Acid)Na2B4O7 + H2SO4 + (5)H2O ======> Na2SO4 + (4) H3BO3 Unfortunately that was the only info I found and I dont know how It can be extracted. It is soluble in water so maybe it can be precipitated out of the spent acid mix....If Na2SO4 wasnt soluble aswell Has anybody here made it? Any suggestions? Help would be much appreciated.Draco, Are you making it for the chemistry fun, or because you need some for use in a pyro comp and can't/don't want to buy any from the pyro suppliers? If it's the latter, just buy it from your local hardware store. It's sold in 99-100% concentration in the pesticide section for killing roaches (cheap, ~$3.00/lb).
kwstag Posted April 25, 2006 Posted April 25, 2006 He's most likely doing it for the chemistry. It's nice to be able to without having to buy it. Other than that I'm sure he knows where to get some.
Douchermann Posted April 26, 2006 Posted April 26, 2006 Well for me, I have to order from a supplier. I've checked every hardware store within a 30 mile radius of my house and none of them sell boric acid as roach killer. They all have some other goofey chemical in there. Or perhaps is it not labeled? maybe as an inactive ingredient?
FrankRizzo Posted April 26, 2006 Posted April 26, 2006 He's most likely doing it for the chemistry. It's nice to be able to without having to buy it. Other than that I'm sure he knows where to get some.Hey, thanks for answering the question for him...real helpful, bud. The reason that I asked that question was that I was on a similar quest a year or two ago, but found it was more work that it's worth. Borax mixed with any strong mineral acid (hydrochloric, phosphoric, sulfuric, etc.) will give you boric acid which precipitates because of relatively low solubility, but washing the precipitate is more work than it’s worth unless he’s is doing it for academic curiosity. As far as not finding the pesticide, look harder. It'll be the active ingredient..orthoboric acid.
Draco_Aster Posted April 26, 2006 Author Posted April 26, 2006 I want to make some for both practical and experimental uses. A while back I bought some chems from a pottery store and when I thought I bought boric acid ( which is what I asked for ) I was sold 1Kg of borax. And why would I want 1Kg of borax sitting on my shelf I agree with you Kwstag, sometimes making chemicals is just as good, if more, rewarding than buying them (depending on how much you are using and how cheap the are )
kwstag Posted April 26, 2006 Posted April 26, 2006 It was a stupid question, bud. That's like asking a pyrotechnician why he makes certain fireworks instead of buying them..
FrankRizzo Posted April 27, 2006 Posted April 27, 2006 Alex, I wasn't being facetious when I asked the question. I was only trying to help Draco find a solution to his problem. While it may be more rewarding from an academic curiosity perspective, synthesizing *all* of your materials is a poor use of your time. I'd rather be screening a batch of pulverone or rolling insert casings than trying to wash the impurities from a chemical that I can buy OTC for less than $3.00/lb. What's your time worth to you?
Draco_Aster Posted April 27, 2006 Author Posted April 27, 2006 Yah I know exactly what you mean. I can only imaging getting my 25Kg bag of KNO3 from shit filled soil. But sometimes I need something to do when im bored or just like to see something fizz and bubble in hot acid
kwstag Posted April 27, 2006 Posted April 27, 2006 I agree with you Kwstag, sometimes making chemicals is just as good, if more, rewarding than buying them (depending on how much you are using and how cheap the are ) Indeed. IMHO, such as Fe2O3 for example... I enjoy making it myself rather than ordering it and waiting.. And it's pretty pure too so I don't complain.
shagaKahn Posted October 29, 2007 Posted October 29, 2007 Not to discourage anyone from synthesizing their own boric acid from borax--but that roach killer suggestion is spot on. Locally, the brands I've found are ROACH AWAY and HOT SHOT MAXATTRAX ROACH KILLING POWDER. Both are nearly pure Boric Acid. Worst case--and if all you need are a few grams--go to the drug store and on the patent nostrum aisle you'll find reagent grade Boric Acid crystals. (They're used to make eye wash).
oskarchem Posted October 29, 2007 Posted October 29, 2007 yeah but you know at drug stores you buy 10g of a chemical and for the same price you could have 500g of it.. You could make some goo with the borax I'm gonna go digging for the synth... Crap I gotta pack haven't done a thing yet! tomorrow a 2am I'm going on vacation... Ok I found it it's actually called Slime:You need:-PVA (polivinic alcochol powder) -Borax -Stirrer -2 Beakers -2 1L bottels Dissolve 40g of Borax in some distilled Water (about 900mL of water),if the borax does not dissolve add some water but just enough to dissolve evrything you can keep this solution in a refrigirator, then the PVA turn: PVA is quite hard to dissolve heat 900mL of distilled water to about 70-80°C and then stir it could take you up to 25mins to dissolve the PVA once evrything is dissolved add 100mL of water (always distilled)If you want you can keep the PVA solution in a refrigirator for several months, then in a beaker add 10mL of borax solution and if you want you can put a colorant into it, in the other beaker you put 100mL of PVA solution, add the Borax to the PVA constantly mixing. Slime has an interesting proptiety that if you hit it hard it will break, but will just flow if you hang it! So have fun with your slime!!
brok3n Posted June 24, 2008 Posted June 24, 2008 So have fun with your slime!! This can also be performed with Guar Gum and Glycerol.http://www.scitech.org.au/index.php?option...=172&Itemid=132
Recommended Posts