Tri-n-propylamine

Physical Properties, (i) Triethylamine, b.p. 90 , tri-n-propylamine, b.p. 156 , tri biitylamine, b.p. 212 ", are liquids with a fishy odour, and with decreasing solubility in water. 

Tri-n-propylamine [102-69-2] M 143.3, b 156.5 , d 0.757, n 1.419, pK 10.66. Dried with KOH and fractionally distd. Also refluxed with toluene-p-sulfonyl chloride and with KOH, then fractionally distd. The distillate, after addn of 2% phenyl isocyanate, was redistd and the residue fractionally distd from sodium. [Takahashi et al. J Org Chem 52 2666 1987.]... 

The 4-chloropyrimidin-2-yl dichlorophosphate ester has been isolated in 58% yield as an intermediate in the chlorination of 6-(trifluoromethyl)uracil with POClj followed by PC15 (83JHC219). The enhanced stability of this compound was believed to be due, in part, to electron withdrawal by the CF3 group. Tri-n-propylamine was found to be the most effective in a comparison of the influence of bases on chlorination with POCl3 (87JHC1243). 

METHYL GROUPS BY REDUCTION OF AROMATIC CARBOXYLIC ACIDS WITH TRICHLOROSILANE-TRI-n-PROPYLAMINE 2-METHYLBIPHENYL... 

The submitters used tri-Ji-propylaniine obtained from Aldrich Chemical Company, Inc., and the checkers used tri-n-propylamine obtained from Wako Pure Chemical Industries, Ltd., Japan. Both groups stored the reagent over Linde type 4A molecular sieves prior to use,... 

The volume of ether added should be sufficient to precipitate most of the tri-n-propylamine hydrochloride in solution. The checkers diluted to a total volume of about 1 1. to precipitate the salt more efficiently. 

Independent evidence for backside attack in gas-phase acid-induced nucleophilic substitutions was provided by a number of studies, carried out using stationary radiolysis." Further confirmation was provided by Morton and coworkers," who investigated the stereochemistry of the proton-induced nucleophilic substitution on (5)-(- -)- and (R)-(— )-2-butanol in the gas-phase at 10 torr in their 70-eV EBF radiolysis reactor. In the presence of a strong base, i.e., tri-n-propylamine... 

PA = 226 kcal moP ), the predominant formation (6.4 to 1) of the (7 ,5 )-di-2-butyl ether over the (R,R) and (5, 5 )-forms is attributed to a simple backside displacement in the proton-bound adduct of the starting 2-butanol enantiomer with inversion of configuration of the reaction site and loss of a molecule of water. When tri-n-propylamine is replaced by the less basic NH3 (PA = 196 kcal moF ), fast neutralization of the proton-bound dimers of the starting 2-butanol is prevented and, therefore, they can grow, producing aggregates that resemble solution microenvironments in which SnI pathways may be accessible as well. In them or in their primary substituted derivatives, consecutive nucleophilic displacements may take place. As a consequence, the stereospecificity of the process is lost and the [(R,S)-di-2-butyl ether]/[(7 ,7 )- and (5, 5 )-di-2-butyl ethers] ratio falls down to 1.2. In this case. 

Figure 1. Yield of pentasil zeolites (percentage crystallization) as a function of time. Abbreviations are C, for mono-n-butylair ne, CU for mono-n-propylamine, C2 for mono-n-ethylamine, C. for mono-n-methylamine, di-C, for di-n-propylamine, di-C, for di-n-propylamine,+di-C2 for di-n-ethylamine, di-n-C.. for di-n-methylamine, TPA Al-free for the aluminium-free synthesis with the tetrapr pylammonium cation, TPA for tetrapropylammonium cation, TEA Al-free for the+aluminium-free synthesis with the tetraethylammonium cation, TEA for tetraethylammonium cation and tri-C for tri-n-propylamine.

An example of reaction type (c) in Table 5-4 is the well-known Menschutkin reaction [30] between tertiary amines and primary haloalkanes yielding quaternary ammonium salts. Its solvent dependence was studied very thoroughly by a number of investigators [51-65, 491-496, 786-789]. For instance, the reaction of tri-n-propylamine with iodomethane at 20 °C is 120 times faster in diethyl ether, 13000 times faster in chloroform, and 110000 times faster in nitromethane than in -hexane [60]. It has been estimated that the activated complex of this Menschutkin reaction should have a dipole moment of ca. 29 10 Cm (8.7 D) [23, 64], which is much larger than the dipole moments of the reactant molecules (tris- -propylamine 2.3 10 Cm = 0.70 D iodomethane 5.5 10-3 1 64 D) [64]. 

In addition to the application of SnI reactions as model reactions for the evaluation of solvent polarity, Drougard and Decroocq [48] suggested that the value of Ig kj for the Sn2 Menschutkin reaction of tri-n-propylamine and iodomethane at 20 °C -termed according to Eq. (7-21) - should also be used as a general measure of solvent polarity. 

Ruff et al. in a series of publications described the synthesis of amine complexes of aluminum hydride [32, 33]. Their study investigated the reaction of these materials with typical Lewis bases in order to define the conditions for the stability of aluminum hydride derivatives in which the aluminum atom exhibits a coordination number of five. They first described methods for making tertiary alkyl amine complexes of aluminum hydride utilizing lithium aluminum hydride and an amine hydrochloride. A finely ground lithium aluminum hydride was placed together with trimethylammonium chloride (ratio 1 2). They prepared other trialkylamine alanes and the N-dialkylaminoalanes, in a similar fashion. These adducts of alane were found to sublime readily at temperatures up to 40 °C except for the tri-n-propylamine alane, which sublimed very slowly and could also be recrystallized from hexane at — 80 °C. 

Dichlorocarbene addition to aikenes. Dehmiow and LisseP have examined the reaction variables in the generation of dichlorocarbene by PTC. Optimal conditions include use of 4 molar excess each of CHCI3 and 50% aqueous NaOH, 1 mole % of catalyst, and efficient stirring. The reaction should be conducted initially at 0-5°, then at 20° for 1-2 hours, and finally at 50° for 2-4 hours. Most quaternary ammonium salts are suitable as catalysts the anions should be chloride or hydrogen sulfate. From the point of cost/efficiency, the most useful are benzyltriethylammonium chloride, tetra-n-butylammonium chloride, Aliquat 336, and tri-n-propylamine. The reaction rate is strongly dependent on the nucleophilicity of the alkene. 

A related reduction utilizing other silicon hydrides has been investigated by Benkeser. Aryl aldehydes and ketones reacted with tiichlorosilane-tri-n-propylamine to give an organosilicon derivative (59 Scheme 17), which on alkaline hydrolysis underwent silicon-hydrogen exchange, and consequently yielded the corresponding hydrocarbons. 

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