06-11-03 05:36
No 439261
Swim distilled a solution of excess paraformaldehyde with water at regular atmospheric pressure to make a formaldehyde solution. The p-formaldehyde dissolved in the water but some didnt dissolve because swim had excess paraformaldehyde. What % formaldehyde solution is left in the recieving flask? Swim is guessing its a 37% solution, as most formaldehyde solutions are. Is this correct. Thanks.
(Hive Addict)
06-12-03 22:49
No 439591
need help^^
(Hive Addict)
06-13-03 08:24
No 439671
(Rated as: good idea!)
| d18 | g.CH2O in 100 cc | g.CH2O in 100 g. |
| 1.0054 | 2.24 | 2.23 |
| 1.0126 | 4.66 | 4.60 |
| 1.0311 | 11.08 | 10.74 |
| 1.0410 | 14.15 | 13.59 |
| 1.0568 | 19.89 | 18.82 |
| 1.0719 | 25.44 | 23.73 |
| 1.0853 | 30.17 | 27.80 |
| 1.1057 | 37.72 | 34.11 |
| 1.1158 | 41.87 | 37.53 |
The values in this table are affected by the presence of methyl alcohol in the formalin solution; since it has been pointed out that technical formalin contains 8–10 per cent of methyl alcohol, the table is not satisfactory for determining the formaldehyde content of technical formalin solutions. For example, a solution containing 37 per cent of formaldehyde and 10 per cent of methyl alcohol would have a density of 1.09 and correspond to 28 per cent of formaldehyde in pure water
Ref:Organic Syntheses, CV1, 377
http://www.orgsyn.org/orgsyn/prep.asp?pr
For those about to synth,we salute you
(Hive Addict)
06-13-03 10:57
No 439696
You may also have lots of trioxymethylene in that flask.
Formaldehyde solution, Formalin, Formol, Morbicid, Veracur (Typharm). A soln of about 37% by wt of formaldehyde gas in water, usually with 10-15%
methanol added to prevent polymerization. This soln is the full strength and also known as Formalin 100% or Formalin 40 which signifies that it contains 40 grams of
formaldehyde within 100 ml of the soln. Colorless liq; pungent odor. On standing, esp in the cold, may become cloudy and on exposure to very low temp a ppt of
trioxymethylene is formed. When evaporated, some formaldehyde escapes, but most of it is changed to trioxymethylene. It is a powerful reducing agent especially in
presence of alkali. In the air it slowly oxidizes to formic acid. d2525 1.081-1.085. One gallon weighs 9.1 lbs. bp760 96 deg. nD20 1.3746. Flash pt 60 deg (140 degF). pH 2.8-4.0.
Misc with water, alcohol, acetone. Keep well closed in a moderately warm place. LD50 orally in rats: 0.80 g/kg (Smyth).
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