09-11-02 08:47
No 355249
Guys an girls, will you help SWiHKAL to answer a question of practical importance? A disclaimer: if the Moderator finds this question more appropriate for Newbee forum, please do move it there!
)So. Recently he's dissolved some Sn in HCl (took a month for the acid to fully react) and now he, naturally, wants to get some dry SnCl2*2H2O from there.
Is it stable to air/temperature?
In other words, if SWiHKAL attempted to evaporate water under draught on a boiling waterbath, would Sn(II) get oxidized appreciably? For that matter, can it bee that it already oxidized over that month?
Or would it bee wiser to simply let it stand in open air until most water evaps and put it into freezer?
Or crush it out w/something?
Bees with experience, please, help! (SWiHKAL would hate to wait a month more for another batch
)Yours,
Antoncho
(Hive Bee)
09-11-02 13:52
No 355290
Ullmann's Encyc. of Ind. Chem.:
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Tin(II) chloride , SnCl2 , is the most important inorganic tin(II) compound. It is produced on an industrial scale by reducing tin(IV) chloride with molten tin, or by direct chlorination of tin.
Solutions of tin(II) chloride are obtained by dissolving metallic tin in hydrochloric acid, or by reducing a solution of SnCl4 with metallic tin.
The anhydrous substance is white, has a greasy luster, and dissolves readily in water, alcohol, ethyl acetate, acetone, and ether. The clear, nondeliquescent, monoclinic dihydrate, SnCl2 · 2 H2O, crystallizes from aqueous solution and is the commercial product.
On dilution, the aqueous solution becomes cloudy as hydrolysis causes precipitation of the basic salt:
SnCl2 + H2O __> Sn(OH)Cl + HCl
The cloudiness can be prevented by small additions of hydrochloric acid, tartaric acid, or ammonium chloride. Because of its strong tendency to hydrolyze, the dihydrate can only be dehydrated over concentrated sulfuric acid or by heating in a stream of hydrogen chloride.
Tin(II) chloride is an important industrial reducing agent, being used to reduce aromatic nitro compounds to amines, aliphatic nitro compounds to oximes and hydroxylamines, and nitriles to aldehydes.
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Merck:
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8939. Stannous Chloride.
Tin dichloride; tin protochloride; Stannochlor.
Cl2Sn; mol wt 189.62. Cl 37.39%, Sn 62.61%. SnCl2.
Prepn: Stephen, J. Chem. Soc. 1930, 2786; Williams, Org. Syn. coll. vol. III, 627 (1955).
Orthorhombic cryst mass or flakes; fatty appearance.
bp 247 deg; d 3.95. Sol in water, ethanol, acetone, ether, methyl acetate, methyl ethyl ketone, isobutyl alcohol. Practically insol in mineral spirits, petr naphtha,xylene.
Dihydrate, crystals; absorbs oxygen from air and forms insol oxychloride. d 2.71. mp 37-38 deg when rapidly heated; dec on strong heating. Sol in less than its own wt of water; with much water it forms an insol basic salt; very sol in dil or in concd hydrochloric acid; also sol in alcohol, ethyl acetate, glacial acetic acid, sodium hydroxide soln. Keep tightly closed, in a cool place.
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A Merck catalogue database says:
dihydrate mp 40.5°C & sol in water = 1187 g/l(20°C)
Conclusions ?:
It probably won't oxidize as long as the soln is not dilute & there's some HCl around.
So evap appropriate amount of water, allow to cool & crystallize. Dry in dessicator (not for too long).
Store in sealed container.
?
Mountain Boy
(Official Hive Translator)
09-11-02 18:11
No 355330
Thanx a lot, M_G, that helps.
Since the soln has been kept over some undissolved Sn, i guess it hasn't oxidized yet - good news.
The huge solubility of the salt in aqua is discouraging, but i still hope smth would xtallize out in the freezer.
Yet - i just KNOW there is a specific proc for SnCl2 isolattion out there, so if someone has it at hand - i'll bee infinitely grateful.
Sincerely,
Antoncho
P.S. M_G - so, are you a boy or a girl?
(Hive Bee)
09-11-02 22:55
No 355392
swihc too tried to make a Sn(II) Chloride. 15grams of 95%Tin solder was placed in a glass bottle and 50mL muriatic acid was added. Soon small bubbles evolved and an hour later the bubbles were pretty furocious. When swihc woke up the solder was all gone and there was some black precipitate settled (maybe the 5% antinomy?)
This surely makes SnCl2 upon evaporation when the black precipitate was decanted, the solution was heated until volume was 20mL or so. White precipitate crashed out and when cooled to 0C , a jar full of white crystals.
I use SnCl2 for sensitizing solutions :)
What do you use SnCl2 for?
hcildoduedn
(Hive Bee)
09-12-02 16:10
No 355617
(Rated as: excellent)
From:
Practical Inorganic Chemistry
G. Pass & H. Sutcliffe
pg. 6, 2nd ed.
Preparation of Tin(II) Chloride
Materials required: Tin foil
Hydrochloric Acid (S.G. 1.18)
Acetic Anhydride
Dissolve tin foil (5 g) in conc. hydrochloric acid and warm the reaction mixture to complete the reaction. Transfer the solution to an evaporating basin, and reduce the volume of solution until crystallization occurs on cooling. Filter off the crystals and dry over CaCl2. The product of the reaction is the compound SnCl2.2H2O, and this may be readily converted to the anhydrous salt by reaction with a readily hydrolysed material, such as acetic anhydride.
Add the crystalline dihydrate (5 g) to acetic anhydride (10 ml) in a beaker. The reaction is vigorous and requires no heating. Carry out in a fume cupboard. The anhydrous salt precipitates from the solution. Filter, wash with a little ether, and dry on the filter.
p.s. I am boy
- please forgive any previous deception due to slight paranoia.Mountain Boy
(Official Hive Translator)
09-12-02 17:59
No 355640
Thank you very much, dear Hcildoduedn and Mountain Boy!
That's exactly what i was hoping for. Jeez, what would we all do w/out our Hive!
M_G - I'm quite amused to learn you're male
- damn it, i almost beegan talking amouresques to you, GawdDear bees! Please, never do pretend to bee of opposite sex, this is SO confusing
- that is, unless you REALLY self-identify with the opposite sex, which is also possibleNevertheless, dear M_B, my best friendly feelings for you didn't diminish a slightest bit
Yours as ever,
Antoncho
(Chief Bee)
09-12-02 19:27
No 355658
unless you REALLY self-identify with the opposite sex
We have had a very knowledgeable PhD student as a member here before, who felt she was a woman trapped in a mans body (and I believe she was taking hormones to correct for this), so it is indeed very possible to come across one of them here.
(Hive Bee)
10-25-02 06:24
No 372419
This is just what I was seeking. A facile/cheap method of producing SnCl2x2H2O.
Here, oddly; SnCl2x2H2O is 50% costlier than plain SnCl2… !
Could this replace Fe/HCl? I f**kin' hope so. Early trials suggest no advantage; only
more of the same… low yields, hard work… low yields, hard work … Barium!
Linoleum: the 13th element! Now available at all good DIY stores… & Walmart.
(Chief Bee)
10-25-02 06:59
No 372427
Dunno about Fe/HCl, but reducing phenyl-2-nitropropenes with iron powder in glacial acetic acid gives 60-70% reliable yield, depending on substrate.
(Stranger)
01-21-03 08:24
No 400116
In case anybody out there was wondering... stannous chloride is used as a mordant (fixative) in dyeing, and is available from specialist crafts suppliers.
Who are you going to believe, me or your own eyes? - Chico Marx in Duck Soup
(Official Hive Translator)
01-21-03 08:47
No 400118
Oh, and an update - the aq. soln of SnCl2 was evap'd directly on a hotplate (no bath) under hood at 'full speed' - until beecame very foamy. On cooling solidified completely (still i don't know how much xtallizational water's in there now- but less than 1 eq.)
But during evaporation i left some Sn granules at the bottom (to avoid air oxidation), don't know if that's important.
Worked great, all in all.
Antoncho