PolytheneSam
(Master Searcher)
02-26-03 17:13
No 412104
      NH4MeSO4 --> NH3MeHSO4
(Rated as: excellent)
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NH4MeSO4  = ammonium methyl sulfate
NH3MeHSO4 = methylamine hydrogen sulfate


From CA vol. 9 page 607

Isomeric transformation of ammonium methyl sulfate and of substituted ammonium methyl sulfates; interaction of amines and methyl sulfate.  EMIL  A. WERNER. Dublin. J. Chem. Soc. 105, 2762-9 (1914). -- The isomerization NH4MeSO4 --> NH3MeHSO4 appears to be a common property of all substituted NH4Me sulfates where such an interchange between a Me and an H is possible.  While the alkyl groups may vary, only the Me sulfates undergo the change.  The isomerization is explained on the basis of dissociation occurring as the 1st step towards more stable equil.  NH4MeSO4  is best prepd. by heating 50 g. MeOH and 100 g. H2SO4 0.5 hr. on the H2O bath, cooling, neutralizing with powdered (NH4)CO3 and a little H2O until a pasty, faintly alk. mass is obtained, extg. with 150 cc. b. MeOH, removing the (NH4)2SO4 from the cold soln., concg. to 0.5 vol., decanting hot, and letting cool.  Yield:  32 g. platelets, m. 137, when rapidly heated, very hygroscopic.  The isomerization was followed by titration with N NaOH, and was very slow until a temp. of about 220 was reached.  At higher temps., the reaction 2 NH4MeSO4 --> C2H4 + 2NH4HSO4 occurs to a slight extent.  Similar results were obtained with NH3MeMeSO4, which m. 52.  PhNH2 and Me2SO4 in PhH gave phenylmethylammonium methyl sulfate, platelets, m. 159, isomerizes readily on warming; Ullman's failure to recognize this was the cause of his incorrect explanation of the action of Me2SO4 on aromatic amines (Ann. 327, 104 (1903)).  The corresponding salt from PhNHMe was obtained as an oil which held PhH tenaciously.  Pr2NH behaved similarly, attempts to drive off the PhH by heat being accompanied by the isomeric change.  NH4EtSO4 is readily prepd. by neutralizing EtHSO4 with (NH4)CO3, using alc. to ext. and recryst. the salt; it forms long, satiny prisms, m. 97, not 62, decomps. at 220 (evolution of C2H4), and is not notably hygroscopic.  Similarly,  NH4PrSO4 m. 132; decomps. 150-60 (evolution of C3H6).  M. HEIDELBERGER.

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    Rhodium
(Chief Bee)
02-27-03 14:13
No 412377
      Here is the full JCS article  Bookmark   

J Chem Soc 105, 2762-2769 (1914) (../rhodium/pdf /ammonium.methyl.sulfate.pdf)