CRSEXP033

=Scheme=

Chemspider: [|Acetone] + [|Propylamine] -> [|N-propyl-2-propanimine] [|Reaction Attempts] =Researcher= Kayla Gogarty =Objective= To observe the reaction of mixing acetone and propylamine at standard temperature and pressure by HNMR spectroscopy with D2O used as the external reference in the outer coaxial NMR tube. =Procedure= Five mixtures of acetone and propylamine were prepared. These five mixtures included pure reagent grade acetone (CRSEXP033A), pure propylamine (CRSEXP033B), a mixture of a 1:1 ratio by volume of acetone and propylamine (CRSEXP033C), a drop of acetone in an excess of propylamine (CRSEXP033D), and a drop of propylamine in an excess of acetone (CRSEXP033E). Five hours later, HNMR spectra were taken of the five mixtures. The mixtures were pipetted into an NMR tube with deuterated water in an outer coaxial NMR tube. Twenty-four hours later, HNMR spectra were taken of the five mixtures with the mixtures pipetted into an NMR tube with deuterated water in an outer coaxial NMR tube. =Results= Time: 5 hours [|CRSEXP033A-NMR1] HNMR Spectrum of Acetone [|CRSEXP033B-NMR1] HNMR Spectrum of Propylamine [|CRSEXP033C-NMR1] HNMR Spectrum of 50/50 by Volume Acetone and Propylamine acetone: 2.674 ppm (6H, s) propylamine: 1.467 ppm (3H, t) N-propyl-2-propanimine: 2.160 ppm (3H, m) [|Mole Fraction Spreadsheet]: acetone 0.16/propylamine 0.32/water 0.34/N-propyl-2-propanimine 0.18 [|CRSEXP033D-NMR1] HNMR Spectrum of One Drop of Acetone in Large Volume Propylamine: No clear product formation - difficulty identifying the acetone peak due to some peak distortion. [|CRSEXP033E-NMR1] HNMR Spectrum of One Drop of Propylamine in Large Volume Acetone: No observed product formation [|Mole Fraction Spreadsheet]

FID Files:

Time: 24 hours [|CRSEXP033A-NMR2] HNMR Spectrum of Acetone [|CRSEXP033B-NMR2] HNMR Spectrum of Propylamine [|CRSEXP033C-NMR2] HNMR Spectrum of 50/50 by Volume Acetone and Propylamine [|Mole Fraction Spreadsheet]: acetone 0.15/propylamine 0.34/water 0.35/N-propyl-2-propanimine 0.16 [|CRSEXP033D-NMR2] HNMR Spectrum of One Drop of Acetone in Large Volume Propylamine: No observed product formation [|CRSEXP033E-NMR2] HNMR Spectrum of One Drop of Propylamine in Large Volume Acetone: No observed product formation =Discussion= Based on the HNMR spectrum, N-propyl-2-propanimine and water were formed during the reaction of acetone and propylamine in the mixture of 50/50 acetone and propylamine by volume. The reaction was completed within five hours. At 5 hours, the ratio of acetone to product was 1:1 and this ratio was the same after 24 hours.

The HNMR spectrum also proved that the impurity in the reagent grade acetone that was used in the experiment is water. Based on the HNMR spectra, the peak of reagent grade acetone with water in the outer coaxial tube is found at approximately 3.1ppm. This peak shifts upfield during reactions with propylamine. For example, the peak shifted to 2.7ppm when there was 50/50 by volume acetone and propylamine. =Conclusion= A 50/50 mixture by volume of acetone and propylamine produced N-propyl-2-propanimine in a ratio of 1:1 acetone to N-propyl-2-propanimine in five hours at room temperature. =Log=

2013-10-23
12:30pm-12:45pm- Five mixtures (CRSEXP033A-E) were prepared 5:20pm-6:00pm- Five mixtures (CRSEXP033A-E NMR1) scanned in NMR at 25.0C with D2O as a reference in an outer coaxial NMR tube Scan Parameters: 8 scans, 1s relaxation delay, 45degree pulse angle

2013-10-24
12:15pm-1:00pm- Five mixtures (CRSEXP033A-E NMR2) scanned in NMR at 25.0C with D2O as a reference in an outer coaxial tube Scan Parameters: 8 scans, 1s relaxation delay, 45degree pulse angle

=Abstract= A new method has been developed that does not require the use of a catalyst. For this method, the reactants are combined in different ratios in glass vials. The mixtures are then placed in a coaxial insert NMR tube with the deuterated solvent in an outer NMR tube. The reaction of acetone and propylamine forms N-propyl-2-propanimine, which is a ketoimine, when there is a 50/50 by volume mixture of the two reactants, one drop of acetone in excess propylamine, or one drop of propylamine in excess acetone. The reaction was monitored and analyzed using HNMR. Based on HNMR spectra, there is 100% conversion when one drop of the reactant is in excess of the other reactant. This reaction was not conducted with an acidic catalyst, but the boric oxide in the glass vial or the coaxial system could have catalyzed the reaction.

=Introduction= The reaction of a ketone and a primary amine produces a ketoimine. An example of this reaction is the reaction of acetone and propylamine to produce N-propyl-2-propanimine.

Figure 1: Reaction of acetone and propylamine to produce N-propyl-2-propanimine

This reaction is typically done in the presence of an acidic catalyst, such as hydrogen chloride [[|1] ,[|2] ]. A new method has been developed that does not require the use of a catalyst. For this method, the reactants are combined in different ratios in Pyrex glass vials. The mixtures are then placed in a coaxial insert NMR tube with the deuterated solvent in an outer NMR tube. The coaxial system is composed of Pyrex [[|3]]. Each mixture is analyzed and observed using HNMR to determine if a product was formed.

Figure 2: Coaxial System composed of Pyrex [[|3]]

=Results= Five mixtures of different ratios of acetone and propylamine were prepared in glass vials. These five mixtures included reagent grade acetone, propylamine, 50/50 by volume acetone and propylamine, a drop of propylamine in excess acetone, and a drop of acetone in excess propylamine. The mole fractions and peak data can be found on the [|Array Table].

Based on this data, the product, N-propyl-2-propanimine, was produced during the 50/50 by volume reaction of acetone and propylamine at room temperature, a drop of acetone in excess propylamine, and a drop of propylamine in excess acetone. There was 100% conversion to the product within five hours when there was a drop of acetone in propylamine or a drop of propylamine in acetone. No catalyst was used during the reaction. After 24 hours, there was no change to the HNMR spectra and therefore, the reaction was completed within five hours.

The data also proves that there is an acetone impurity in the propylamine reagent bottle because N-propyl-2-propanimine is present in the HNMR spectrum for propylamine.

=Discussion= N-propyl-2-propanimine was formed from a mixture of 50/50 by volume acetone and propylamine with a ratio of 1:1 acetone to product at room temperature. The product was observed in the HNMR spectrum with a multiplet peak at 2.160ppm. A ketoimine, such as N-propyl-2-propanimine, is formed from the reaction of a ketone and primary amine. According to literature, this reaction is typically done in the presence of an acidic catalyst, such as hydrogen chloride [[|1] ,[|2] ]. However, the reaction was performed without an acidic catalyst by mixing the reactants in a Pyrex vial. Pyrex glass, or borosilicate glass, is composed of silica sand and boric oxide [[|4] ]. Boric oxide, which is an acidic component, can be an effective catalyst [[|5] ]. Therefore, the boric oxide component of Pyrex glass could have catalyzed the reaction. The experiment also proved that the impurity in the reagent grade acetone, which is present at 3.1ppm, is water. Based on the HNMR spectra, the peak shifts upfield during reactions with propylamine.

=Conclusion= HNMR can be used to monitor the reaction of acetone and propylamine with different mole fractions of reactants. This reaction forms N-propyl-2-propanimine, which is a ketoimine, when there is a 50/50 by volume mixture of the two reactants. The formation of this product is proven by the multiplet peak at 2.160ppm. The product was also formed during the reactions of one drop of acetone in excess propylamine and one drop of propylamine in excess acetone. For these reactions, there was 100% conversion to the product. The formation of the product is proven by the multiplet peaks at 2.125ppm and 2.57ppm, respectively. This reaction was not conducted with an acidic catalyst, but the boric oxide in the glass vial or the coaxial system could have catalyzed the reaction.