Make Formic Acid and Hydroxylamine in one step!!

[foxy2]

Hello boys and girls.  I am happy to report that we have found ourselves a winner here!!!

Ahheemmm

To 200 mL of methanol were added 30 grams of nitromethane and 60 grams of oxalic acid.  The resulting mixture was stirred to form a solution.  The solution was then refluxed at atmospheric pressure at a temperature ranging from 60 to 70C(refluxing), for 20 hours.  Hydroxylamine and formic acid were obtained.

United States Patent  3,380,807 
Current U.S. Class: 423/387; 562/606 



Now isn't that handy???
Seems a wee bit better than the synth at Rhodium's.
I know SO2 and Barium salts are fun and all butttt....



Oh Yea
Post reaction I think you can crash out hydroxylamine sulfate with H2SO4, assumeing the solution is not to wet. Or you can baseify and vacuum distill out the hydroxylamine freebase.  Then add H2SO4 and distill your formic!!

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[catastrophe]

Nice! Shit, you are like a fox!
Anything about yields?

[Antibody2]

sweet indeed foxy   ,

i wonder whether the bases used(NaAc or Na2HCO3) for oximation would still be required if starting from the freebase? or would the hydroxylamine form a formate salt, complicating workup?
"All those memories lost like rain..."

[Rhodium]

Ketone + HONH2 (freebase) => Oxime + water. If you use the freebase, the base should not be necessary.

If hydroxylammonium formate is fully soluble in methanol, then a sparingly soluble salt could be made by the addition of the appropriate acid. The freebase can be vacuum distilled (bp 58°C at 22 mmHg) but is unstable in its freebase form and should be converted into a salt as quickly as possible.

[lugh]

Isolation of hydroxylamine free base can be problemetical (besides the explosion risk), normally this leads to decomposition into ammonia. One procedure that has worked is to form the phosphate and distill under diminished pressure [Ann. 307, 333 (1899) & 311, 117 (1900)].
This reaction was originally discovered by Victor Meyer, some more related references are: Ann. 180, 163 (1876); J. Prakt. Chem., (2) 7, 480 (1873) & (2) 8, 309 (1873) &  Ber. 10, 776 (1877)  

[halfapint]

CRC says hydroxylamine formate melts at 76^o, decomposes at 80. When it does, hydroxylamine (b.p. 56.5^o) is already in the vapor phase, whether Lugh has cautioned us about it or not. I want to see that patent, but espace is down right now. Very curious to know what they say about recovery of the products. foxy2 could have saved us all a lot of worry, by sketching in some of these details... Well, it says oh yea up there now. Either foxy2 edited while I was posting, or I just overlooked it.  

If the two products do salt each other (well they do, no doubt) then acid hydrolysis is probably called for, distilling off the formic acid and leaving the hydroxylamine as its salt. This takes Lugh's caution into account. I never realized hydroxylamine is liquid in such a narrow temperature range: mp 33, bp 56. The free base is a solid at room temp.
turning science fact into <<science fiction>>

[Rhodium]

The hydroxylamine freebase bp quoted by me was at 22 mmHg. The mp of hydroxylamine freebase is 33°C.

A suggestion for isolation would be to (as you said) add HCl to the reaction mixture, and distill off the formic acid together with the methanol. The residue that could be crystallized from the concentrated mother liquor would be the hydrochloride salt.

[lugh]

Reported melting points for the pure hydrochloride salt are between 151-7 degrees C  

[Rhodium]

Patent US3380807

Preparation of hydroxylamine and monocarboxylic acids from primary nitroparaffins and oxalic acid

Abstract

A process for preparing hydroxylamine and moncarboxylic acids by reacting a primary nitroparaffin, for example 1-nitropropane, with oxalic acid.

This invention relates to a process for the production of hydroxylamine and monocarboxylic acid. In a particular aspect this invention relates to a process for the production of hydroxylamine and monocarboxylic acid by reacting a primary nitroparaffin with oxalic acid.

In U.S. Patent 2,381,410, it is disclosed that hydroxylamine and monocarboxylic acid are obtained by heating a primary nitroparaffin and hydrochloric acid in the presence of a monocarboxylic acid. Acetic acid, propionic acid arid butyric acid are specifically mentioned for use in the process. It is stated in the patent that the monocarboxylic acid of use in the process served principally as a solvent for the primary nitroparaffin and the hydrochloric acid.

In the prior art process the hydroxylamine is obtained as the crystalline salt of hydrochloric acid (hydroxylamine hydrochloride). When other forms of hydroxylamine are desired it is necessary to dissolve the crystalline salt in a suitable solvent such as water or methanol and then convert the hydroxylamine to the desired form.

It is an object of the present invention to provide a process for the production of hydroxylamine and monocarboxylic acid.

A further object of the present invention is the provision of a process for the production of hydroxylamine and monocarboxylic acid without the employment of hydrochloric acid in the reaction step.

Further objects and advantages of the present invention will be apparent from the specification and the appended claims.

It has been discovered in accordance with the present invention that monocarboxylic acid and hydroxylamine are obtained by reacting a primary nitroparaffin with oxalic acid without the employment of hydrochloric acid in the reaction step. Acetic acid, propionic acid and butyric acid are not successfully employed as the organic acid of use in the present invention. The reaction results in the conversion of the primary nitroparaffin to the corresponding monocarboxylic acid and to hydroxylamine. For example, propionic acid and hydroxylamine result from the reaction of 1-nitropropane and oxalic acid. The reaction is illustrated as follows:

1-nitropropane + oxalic acid => propionic acid + hydroxylamine

The nitroparaffins of use in the present invention are primary nitroparaffins that is to say nitroparaffins where-in the nitro group is bonded to a carbon atom which is in turn bonded to at least two hydrogen atoms. Typically suitable primary nitroparaffins are represented by the formula R-N02 wherein R is an alkyl radical having from one up to about seven carbon atoms. Representative primary nitroparaffins include nitromethane, 1-nitrohexane, nitroethane, 1-nitropropane, 1-nitropentane, 1-nitrobutane, 1-nitroheptane, etc., and the like. Monocarboxylic acids prepared from such typical primary nitroparaffins are represented by the formula R-NO2 wherein R is an alkyl radical having from one up to about six carbon atoms. Representative monocarboxylic acids prepared in accordance with the present invention include formic acid, acetic acid, butyric acid, propionic acid, etc., and the like.

In accordance with the present invention a primary nitroparaffin and oxalic acid are reacted to obtain hydroxylamine and monocarboxylic acid. The process of the invention is suitably carried out by heating the primary nitroparaffin and the oxalic acid under reflux conditions, preferably in the presence of an inert solvent, that is to say a solvent inert to the reactants and the reaction products. Examples of such solvents are water, methanol, ethanol, propanol, butanol, etc., and the like. The use of methanol is preferred. A weight ratio of solvent to reactants of in excess of 2:1, for example from about 5:1 to about 20:1, is typically employed.

The temperatures employed in the present invention may vary and will depend among other things on the particular nitroparaffin employed and on the particular inert solvent employed. For example, when the reaction is carried out under reflux conditions with methanol as the solvent and 1-nitropropane as the nitroparaffin, temperatures in the range of about 60 to about 70° C. are typically employed at atmospheric pressure. When butanol is substituted for methanol as the solvent of the process, temperatures in the range of about 115 to about 125° C. are typically employed at atmospheric pressure.

The mole ratio of oxalic acid to primary nitroparaffin is of importance in the present invention. While hydroxylamine and monocarboxylic acid are obtained at lower ratios, best results are obtained when the mole ratio of oxalic acid to primary nitroparaffin is in excess of 1:1, for example in the range of about 2:1 to about 5:1.

The hydroxylamine and monocarboxylic acid produced according to the process of the present invention may be recovered from the reaction medium by any suitable procedure. For example, the hydroxylamine may be recovered as free hydroxylamine by neutralization of the reaction medium with a suitable base followed by distillation of the neutralized reaction medium under reduced pressure to remove the free hydroxylamine. The hydroxylamine may also be precipitated from the reaction medium as the salt of oxalic acid by cooling and concentrating the reaction medium. The hydroxylamine may also be recovered as the salt of a strong mineral acid such as sulfuric acid or hydrochloric acid by methods known to the art.

The invention will be understood more fully by reference to the specific examples. It is understood that the examples are presented for purposes of illustration only and are not inteaded as a limitation of the invention.

Example 1

To 200 ml. of methanol were added 30 grams of 1-nitropropane and 60 grams of oxalic acid. The resulting mixture was stirred to form a solution. The solution was then refluxed at atmospheric pressure at a temperature ranging from about 60 to 70° C. for 20 hours. Hydroxylamine and propionic acid were obtained.

Example 2

The procedure of Example 1 was repeated with the exception that at the end of the 20-hour period aqueous hydrochloric acid was added to the reaction medium. The reaction medium was then distilled to remove propionic acid. The distilled reaction medium was then evaporated to dryness under vacuum. Hydroxylamine hydrochloride was obtained.

Example 3

The procedure of Example 1. is repeated in all essential details with the exception that 1-nitroethane is substituted for 1-nitropropane and butanol is substituted for methanol. Acetic acid and hydroxylamine are obtained.

Example 4

The procedure of Example 1 is repeated in all essential details with the exception that nitromethane is substituted for 1-nitropropane. Formic acid and hydroxylamine are obtained.

Example 5

The procedure of Example 1 is repeated in all essential details with the exception that 1-nitrobutane is substituted for 1-nitropropane. Butyric acid and hydroxylamine are obtained.

[foxy2]

I assumed people could look up the patent easily on their own(www.uspto.gov) because I have no way to easily convert TIFF files to text and typeing the whole thing is not my idea of fun!

lugh warned that distilling hydroxylamine freebase is an explosion hazard, therefore I would avoid this unless you know how its done properly(I would assume a strong vacuum, but don't know) 

So how in the world can we get nice hydroxylamine freebase for reacting with a keytone??

There is a procedure for hyrooxylamine freebase in alcohol solvent.  I will get better details when I can.  Here is an overview of what i remember.

Hydroxylamine Freebase in Alcohol
Hydroxylamine sulfate(powdered) is dispersed in 50/50 methanol/propanol, it does not dissolve.  Ammonia gas is bubbled in to convert hydroxylamine sulfate to freebase, which dissolves, while precipitateing ammonium sulfate.  When you think you are done, add a bit more hydroxylamine sulfate to consume any leftover NH3. Then filter off any solids, ammonium sulfate and unreacted hydroxylamine sulfate.  The result is a relatively pure hydroxylamine freebase in alcohol.

Hows that???




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[Dr_Sister]

Sweet, that's how, whatta kickass thread! this one's certainly earned a spot on my CD! you two have improved my mood immeasurably!
7.10.01

[Rhodium]

Please report back any experimental details using this method, I believe the patent is pretty sketchy, especially when it comes to the isolation of the hydroxylamine as a salt.

[foxy2]

Here is a procedure for aqueaous freebase.  I assume hydroxylamine(bp 107C) distills over with water(bp 100C) thus limiting the explosion hazard.  However this could be very dangerous also. I don't have the exact details of the patent only the abstract.

Japanese Patent JP2000211906

PROBLEM TO BE SOLVED: To provide an aqueous solution of free hydroxylamine essentially free from salts and organic materials and having high purity and high concentration.
SOLUTION: This process for producing an aqueous solution of free hydroxylamine comprises the reaction of an aqueous solution or slurry containing hydroxylammonium sulfate with an alkali to form an aqueous solution or slurry containing free hydroxylamine and a dissolved or partly precipitated sulfate, the mixing of the obtained aqueous solution or slurry with a lower alcohol to precipitate a solid sulfate, the separation of a liquid containing the lower alcohol and a part of water by the distillation of the aqueous solution after the separation of the solid sulfate and the distillation of the residual liquid to obtain the aqueous solution of free hydroxylamine as the distillate.
 
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[foxy2]

Rhodium
The sulfate salt is not soluble in alcohol, therefore adding H2SO4 and ppt it should be realatively simple.  I assume oxalic acid and formic are fairly soluble in the alcohols.  I can think of nothing else that would ppt from H2SO4 except maybee some residual NH3?
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[foxy2]

Continuous purification of hydroxylammonium salts.     Kalab, Vladimir; Mazurova, Alzbeta; Cuciak, Jozef.    Povazske Chem. Zavody, N. P.,  Zilina,  Czech.    Chem. Prum.  (1976),  26(3),  123-5.  CODEN: CHPUA4  Journal  written in Czech.    CAN 85:162604    AN 1976:562604    CAPLUS
 
Abstract
The soln. of hydroxylammonium salt contg. high concns. of acid and ammonium salts is treated with a ketone to form an oxime.  The oxime is extd. with trichloroethylene and then the oxime-trichloroethylene soln. is treated with an acid soln. to form a more pure hydroxylammonium salt.
 
(Preparation); PREP (Preparation)   (purifn. of, acetone in) 
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[foxy2]

Preparation of hydroxylamine and aldehydes from alkali metal salts of primary nitroparaffins and organic acids.

US Patent 3386803

Abstract
H2NOH and aldehydes are produced by the reaction of a water-sol. alkali metal salt of a primary nitroparaffin with HCO2H or oxalic acid, optionally in the presence of an inert solvent.  Thus, a soln. of 10 g. PrNO2 and 4 g. NaOH in 100 ml. water was added slowly to 50 ml. HCO2H and the mixt. stirred 90 min. and combined with aq. HCl to give EtCHO and 51% H2NOH.HCl.  A soln of 10 g. PrNO2 and 4 g. NaOH in 100 ml. water was added slowly to 25 g. oxalic acid in 200 ml. MeOH and the mixt. treated as above to give EtCHO and H2NOH.  Similar treatment of EtNO2 and BuNO2 gave the corresponding aldehydes and H2NOH. 
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[foxy2]

Here is the reference I promised

Manufacture of pure hydroxylamine or solutions thereof.

German Patent DE 1247284 

Abstract
Hydroxylammonium chloride has been used heretofore for making H2NOH because of its soly.  The cheaper hydroxylammonium sulfate (I) is suitable for the manuf. of H2NOH by making a fine suspension of I in an alc. contg. (shows a less than or equal to sign) 3 C and treating with NH3.  The insol. I that remains and the (NH4)2SO4 formed in the reaction mix are readily sepd.  Thus, finely ground I 246 g. is suspended with stirring in a mixt. of MeOH 250 and PrOH 250 ml. and NH3 is introduced at a rate of 20 l./hr.; the temp. rises from .apprx.20° to 45° and after .apprx.3 hrs. the reaction ceases as can be noted by the escape of NH3.  An addnl. 20 g. of I is added and the mixt. is stirred for another hr.  After cooling, the excess I and (NH4)2SO4 are filtered off to provide a soln. of H2NOH 95.7 g., corresponding to a yield of 89.2%. 
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[foxy2]

Hydroxylamine purification via ion exclusion.    
US  4147623 

Abstract
NH2OH is sepd. from aq. solns. contg. H3NOH+ salts in mixt. with salts of cations whose corresponding bases have been dissocn. consts. ³10-7.  The aq. soln. is adjusted to pH 6-11 and then the soln. is passed through a cation-exchange resin bed loaded with charge-compensating ions which compose a base or an anion-exchange resin or with charge-compensating ions which compose an acid.  A 1st effluent is removed from the bed contg. predominantly cations eluted from the cation exchange resin or anions eluted from the anion-exchange resin.  A later effluent contg. NH2OH is obtained. 

Cation/Anion Exchange Resins are otc if you know where to look.


Preparation of high-purity hydroxylamine sulfate from an impure solution.
RO  95695  
Patent  written in Romanian.
 
Abstract
An impure dil. soln. contg. hydroxylamine sulfate is treated with acetone or MEK at pH 6-7 and 50-100°, the oxime formed is extd. with CCl4, C2H4Cl2, or C2H2Cl4 and then hydrolyzed by boiling with 5-15% H2SO4 or HCl soln.  High-purity (e.g., 98%) hydroxylamine sulfate is isolated by known methods (e.g., crystn.). 

Fully Informed Jury!

(http://www.fija.org/)

[PolytheneSam]

In

Patent US2749217

column 1 lines 50+ it mentions making hydroxylamine from nitromethane using H2SO4.
http://www.geocities.com/dritte123/PSPF.html
The hardest thing to explain is the obvious

[moo]

Patent GB833118

describes a reaction between 1-nitropropane and sulfuric acid resulting in hydroxylammonium sulphate and propionic acid. This might be adapted to nitromethane because they say the minimum reaction temperature is 90°C which is below the boiling point of nitromethane.