Acetaldehyde ammonia, trimer

Acetaldehyde ammonia trimer (hexahydro-2,4,6-trimethyl-l,3,5-triazine trihydrate) [76231-37-3] M 183.3, m 94-96 , 95-97 , 97 , b 110 (partly dec). Crystd from EtOH-Et20. When prepared it separates as the trihydrate which can be dried in a vacuum over CaCl2 at room temp to give the anhydrous compound with the same melting point. The dihydrate melts at 25-28° then resolidifies and melts again at 94-95°. IRRITATES THE EYES AND MUCOUS MEMBRANES. [J Org Chem 38 3288 1973.]... 

To a sample of povidone (Kollidon 30 batch 822) different amounts of acetaldehyde-ammonia trimer (=Hexahydro 2.4.6-trimethyl 1.3.5 triazine, C6H15N3 3H20, CAS number 76231-37-3, available at Fluka/Sigma Aldrich) were added and determined enzymatically. The acetaldehyde in this Kollidon batch was 45 mg/kg before the addition (Table 44). 

Added acetaldehyde -ammonia trimer (calculated as acetaldehyde) [mg/kg] Theoretical content of acetaldehyde [mg/kg] Found acetaldehyde [mg/kg] Recovery rate [%]... 

Acetaldehyde ammonia trimer (hexahydro-2,4,6-trimethyl-l,3,5-triazine trihydrate)... 

Acetaldehyde ammonia AI3-52423 Aldamine EINECS 200-868-2 Ethanol, 1-amino- Hexahydro-2,4,5-trimethyl-s-tria2ine trihydrate UN1841 Velsan. Exists as a trimer which is used in the manufacture of plastics and as a pickling inhibitor for steel, and is a rubber vulcanizing accelerator. A proprietary rubber vulcanizabon accelerator. Crystals mp = 97° bp= 110° soluble in H2O, less soluble in EtzO. 

Nicotinic acid Nicotinic acid, pyridine-3-carboxylic acid (20.2.9) is synthesized industrially by heating a paraldehyde trimer of acetaldehyde, under pressure with ammonia, which leads to the formation of 2-methyl-5-ethylpyridine, followed by oxidation with nitric acid which gives the desired product [22-25]. 

Ammonia reacts with formaldehyde to give hexamethylenetetramine (3.13) and with acetaldehyde to give a trimer (3.14). Other more steric-ally hindered imines remain as the monoadduct and do not add a. second molecule of amine. These imines are readily reduced by, for example, sodium cyanoborohydride to form amines or they may be hydrolysed to regenerate the carbonyl compound. 

ACETALDEHYDE TRIMER (123-63-7) Forms explosive mixture with air (flash point 62°F/17°C). Reacts with strong acids, caustics, ammonia, amines, oxidizers. Decomposes on contact with acids or acid fumes, forming acetaldehyde. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

Pentafluorobenzalddiyde reacts with bistrifluoromethyl nitroxide (see also p. 414) to give the amino-oxy-compound C6Fs CX>2-N(CF3)s, with the monohydrazide of cyclic trimeric phosphonitrile fluoride to give the hydrazone (117), and with ethyl acetoacetate and ammonia to give the expected dihydropyridine derivative (118). (Pfcntajauorophenyl)acetaldehyde is obtained in excellent yield from 2-(pentafluoropheny])ethanol and sodium dichromate in dimethyl sulphoxide the solvent may prevent further oxidation of the aldehyde. ... 

Production is carried out by liquid-phase synthesis from acetaldehyde and ammonia. Acetaldehyde is first trimerized to paraldehyde. The subsequent reaction with aqueous ammonia, which gives a 70% yield of 5-ethyl-2-methylpyridine, is performed in the liquid phase at 230 °C and at a pressure of around 150 bar with ammonium-salt catalysts. 

The reaction of aldehydes and ketones with ammonia (NH3) itself is shown as the first item in Table 9.4. Despite the apparent simplicity of the process shown in Scheme 9.65, the reaction of aldehydes and ketones with this nucleophile (base) often produces a complex mixture of products because the addition process does not stop after the first step. For example, methanal (formaldehyde, H2C=0) yields hexamethylenetetramine (Table 9.4) and ethanal (acetaldehyde, H3CCHO) provides the corresponding C-methylated trimer. However, diarylketones (At20=0) often give stable imines (Equation 9.51). 

Problem 9.9. The reaction of methanal (formaldehyde, H2C=0) with ammonia (NH3) is used to prepare l,3,5,8-tetrazatricyclo-[3.3.1.1 ]decane (hexamethylenetetramine) (Thble 9.4). Write a plausible series of reactions between these reagents that would have the desired product as the outcome. Account for the different result to produce the trimer (shown below) with ethanal (acetaldehyde) and ammonia. 

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