>>140089Какой яндекс? Наш путь это google scholar и patents
Preparation of triacetoneamine according to US 6,646,127
The patent's procedure in example 22 was followed, using CaCl2 as catalyst.
NH4NO3 was prepared by reacting 53% HNO3 with 30% NH4OH (very vigorous reaction), evaporating the water and drying the salt by melting it.
Acetone was technical grade, CaCl2 pellets were powdered prior to addition.
Procedure
In a 500mL 3-neck RBF, 5g (45mmol) of powdered CaCl2 and 40g ( 0.5 mol) of dry NH4NO3 wee suspended in 220mL acetone. 31mL (0.5 mol) of 30% NH4OH (Panreac) were charged in the addition funnel, and slowly added dropwise, over 20min.
At first there was a little caking of the solids, then gradual dissolution. The flask warmed up to 40-45°C, so an ice bath was applied to keept temp under 30°C. Once the addition was finished, most of the solids had dissolved to give a limpid solution.
The reaction medium was then stirred at RT for 7H total. The slightly yellow solution gradually turned orange then red, with that caracetistic "fluorescent" red tint near the end.
The condenser was then replaced by a fractional distn setup, with a short (200mm vigreux column). The acetone was removed under slight vacuum at 45°C over a 80°C oil bath. the reaction mixture had a strong smell of TAA. The colorless distillate smelled strongly of ammonia. Distn was continued until no more acetone was distilled, and water started to take-off.n A dark red residu remained.
After cooling down to 30°C, the very viscous blood red residu whic smelled strongly of TAA was transfered to a 1L seperating funnel, and extarcted with 4*50mL toluene. The extarcts came out golden orange, leaving the blood red color in the viscous aq. layer. After the 4 extraction, the aq. didn't really smell as TAA anymore, but more as ammonia. The toluene extracts were combined, washed with 50mL conc. K2CO3, and brine, thend ried over K2CO3 in a stoppered erlenmyer for 20min. The extract was then transfered to a 500mL beaker, and acidified with 20% v/v H2SO4 in IPA. At first, a white precipitate formed, but as acidification continued, a dark brown tar_like resin preicpitated also, very similar to the other TAA workups.
There was still a certain amount of white precipitate in suspension. After standing for 5min, most of the suspension was vacuum filtered, leaving most of the resin in the beaker. 100mL acetone:IPA 50:50 were added, and the resin triturated, dissolving most of theresin and freeing more clear solid. The suspension was vacuum filtered, thoroughly triturated on the buchner with 50mL acetone, and 50mL acetone:pet ether 50:50 before drying by suction for 5min. The fine beige precipitate was then placed in a glass cup and dried under a lamp to afford 10.81g (41mmol) of crude 2,2,6,6-tetramethylpiperidone hydrosulfate.
The aqueous layer was re-extracted with 4*50mL AcOEt. These extracts took on a much redder colour. The combined extarcts were washed with 50mL co,nc. K2CO3, brine, and dried over Na2SO4.
This extract was also acidified until acidic on dampened pH-paper with the same H2SO4/IPA, giving a very fien white precipitate at first, then a brown/purple voluminous solid. This solid was much harder to correctly clean, giving a sticky paste, and required larger amounts of acetone, IPA and AcOEt to get it relatively clean. The sticky paste finally dried, giving a crunchy brown solid (4.2g).
The two batches will be recrysatllied from MeOH/pet ether or MeOH/AcOEt.