Ammonia tert-butylamine

The effect of the Si/Al ratio of H-ZSM5 zeolite-based catalysts on surface acidity and on selectivity in the transformation of methanol into hydrocarbons has been studied using adsorption microcalorimetry of ammonia and tert-butylamine. The observed increase in light olefins selectivity and decrease in methanol conversion with increasing Si/Al ratio was explained by a decrease in total acidity [237]. 

Potassium nitrate, Sulfuric acid, 1,3,5-Trifluorobenzene, Methylene chloride, Hexane, Tert-butylamine, Trifluoroacetic acid, 1,2-Dichloroethane, 3-Amino-1,2,4-traizole, Glacial acetic acid, Sodium nitrite, Urea, Ethyl acetate, Dimethylformamide, Diethyl ether, Sodium sulfate, Methanol Ethanolamine, Diethyl ether, Ethyl chlorocarbonate, Sodium hydroxide, Magnesium sulfate, Nitric acid, Anhydrous ammonia... 

Similarly, zeolites can catalyze the addition of ammonia to an olefinic double bond, as is exemplified by the BASF process for the production of tert-butylamine by reaction of isobutene with ammonia, in the vapor phase, over a rare earth exchanged ZSM-5 or Yzeolite (Fig. 2.20) [58, 59]. This process has an atom efficiency of 100% and replaced a conventional synthesis via a Ritter reaction, which employs HCN and sulfuric acid and generates formate as a coproduct. 

Violent reaction or ignition under the proper conditions with acetone + tert-butylamine, alcohols + nitric acid, aluminum carbide, ammonia + sulfuric acid, antimony, coal + peroxomonosulfuric acid, dichloromethylsilane, dimethyl sulfoxide, ethanol + sulfuric acid, glycerol, concentrated hydrofluoric acid, hydrogen peroxide, hydrogen trisulfide, hydroxylamine, carhon, organic nitro... 

Sodium bis-(2-methoxyethoxy)aluminium hydride (ref. 84) and lithium tri-tert-butoxyaluminium hydride (ref. 85) showed excellent stereoselectivity for podophyllotoxin compared with other reagents. However, these reagents have the disadvantage that low temperature (-75 C) is required to obtain satisfactory yield. Although the stereoselectivity was inferior to that of the above-mentioned aluminium hydride complexes, borane-terf-butylamine complex (ref. 86) and borane ammonia complex (ref. 87) gave the products in more than 90% yield. The reactions proceeded at room temperature, and borane-tert-butylamine complex did not require the use of a nitrogen stream. 

The production of tert-hutylamine is interesting for the fact that this amine has been used to demonstrate the technical potential of hydroamination in commercial amine production [route (b) in Topic 5.3.4]. BASF introduced in the early 1990s the first process that operates vith a zeolite catalyst and converts isobutene directly with ammonia. The reaction is carried out by contacting the supercritical reaction mixture with the catalyst at temperatures between 250 and 300 °C and at pressures between 200 and 350 bar. Under equilibrium conversion conditions tert-butylamine forms in 95% selectivity. 

The current experiment involves the preparation of the sterically hindered amine A -ferf-butyl-3,5-dimethylaniline. Other preparations of this amine involve addition of methyllithium to lV-3,5-dimethylphenylacetone imine and the reaction of l-bromo-2,4-dimethylbenzene with terf-butylamine either via aryne formation or by palladium-catalyzed alkylation. The current method, the reaction of tert-butylamine with the 2,4,6-trimethylpyrylium cation, involves inexpensive starting materials and proceeds in high yield. The molybdenum(III) complex of the deprotonated form of this amine, Mo[N(f-Bu)(3,5-C6H3Me2)]3, splits the N=N triple bond in N2 to afford molybdenum(VI) nitrido products. This latter reaction is the key step in the recently discovered catalytic process to convert N2 to ammonia under ambient conditions. 

Zinc methylphosphonate intercalates aliphatic amines with no branching at the a-position, for example n- and o-butylamines the sec- and tert-butylamine isomers are excluded because of steric restriction by the mediylphosphonate group (13a). In the case of zinc phenylphosphonate (Hgure 2), access to the site vacated by the water molecule is sufficiently restricted that only ammonia is intercalated, and aliphatic amines are excluded (13b). The excellent shape-selectivity of these reactions suggests the possibility of making sensors for amines and ammonia from zinc phosphonates, provided the intercalation event can be transduced to an observable (electronic, optical, mechanical, etc.) signal. 

While the response of this device is rapid, the irreversibility of ammonia binding at room temperature places serious limitations on the use of zinc phosphonates in practical sensors. Another problem with devices derived from colloidal particles is the large external surface area, on which molecules other than the desired analyte can adsorb. This point is Ulustrated in Figure 4. Despite the fact that butylamine isomers are excluded from intercalation into bulk Zn(03PC6Hs), Ae mass change upon exposure of the device to either n- or tert-butylamine vapor is comparable to that found for ammonia. Adsorption of these interfering analytes is also quite slow, occurring over a period of hours. 

Figure 7. Frequency change vs. time for exposure of a 5-layer copper biphenylbisphosphonate QCM device to ammonia (6.8 % by volume in Ar), and gas phase n- and tert-butylamine (1.4 % and 6.6 % in Ar, respectively). Airow indicates beginning of Ar purge for the /

---