No. 21161 INVESTIGATING A SAPONIFICATION
REACTION USING THE DIAMAXATR™ INTRODUCTION sunflower oil film was placed on the diamond. The film was Diamond ATR is a useful pressed against the diamond tool in analyzing reactions with ATR crystal using the pressure certain types of corrosive applicator. After a spectrum was samples, such as harsh cleaning taken of the burned sunflower agents. Manufacturers in this oil film, the pressure applicator industry can study potential was raised, and two drops of unwanted by-products as well as oven cleaner was deposited on the effectiveness of the cleaning the film. The pressure applicator agent. was used to keep the film firmly In this note, a saponification pressed against the crystal. reaction was examined using Spectra were collected every 30 oven cleaner and burned seconds for a total of 45 minutes sunflower by diamond ATR using Harrick’s TempLink spectroscopy. software.
Figure 1. The DiaMax ATR. EXPERIMENTAL RESULTS AND DISCUSSION
Infrared spectra were Although the active
90 collected on an FT-IR ingredient in oven cleaner is spectrometer equipped with the sodium hydroxide, which 70 Harrick DiaMaxATR™ single- contains an –OH functional
50 reflection high throughput group, it is clear from the Transmittance [%] characteristic broad band at
30 diamond ATR accessory. -1 3500 3000 2500 2000 1500 1000 500 Spectra were collected at an 8 3333 cm and the band at 1638 -1 -1 Wavenumber cm-1 cm resolution, a gain of 1, and cm (Figure 2) that the active signal averaged over 32 scans. ingredient in the oven cleaner is Figure 2. ATR spectrum of The aperture was set to 100%. diluted with water. oven cleaner. Spectra were collected in the Figure 3 is the burned range 4000-400 cm-1. The sunflower oil film sample, which
90 instrument was purged to reduce shows a weak broad band -1
80 water vapor and CO2 present in the 3400-3500 cm spectral range, which indicates
70 interferences. Transmittance [%] The samples used were O-H stretching. There are two 60 EasyOff Heavy Duty Oven peaks present in the 3000-2850 3500 3000 2500 2000 1500 1000 500 -1 -1 Wavenumber cm-1 Cleaner and Sunflower oil cm spectral range, 2922 cm (H&B Oils Center Co.). and 2853 cm-1, which are due to Figure 3. ATR spectrum of Approximately 14 ml of C-H stretch vibrations. A burned sun flower oil. sunflower oil was place in a prominent peak found at 1740 glass container and was heated cm-1 is likely attributed to the in an oven at 260 °C for 2 hours. ester carbonyl group found in A small piece of the burned INVEST IGATING A SAPONIFICATION REACTION USING THE DIAMAXATR™ triglycerides in the sunflower burned sunflower oil and oven oil. cleaner mixture at 45 minutes The active ingredient in oven and a spectrum of oven cleaner 90 cleaner, sodium hydroxide, drying at 45 minutes was hydrolyzes the triglycerides, compared to confirm whether a 80
producing carboxylate salt and saponification reaction occurred 70 an alcohol, known as a or if the oven cleaner drying Transmittance [%] saponification reaction. Figure 4 concentrated the ingredients 60 illustrates the changes upon the previously obscured by water. 3500 3000 2500 2000 1500 1000 500 introduction of oven cleaner to As the oven cleaner dries, the Wavenumber cm-1 burned sunflower oil at the broad –OH band shifts to a Figure 4. ATR spectra of burned beginning of the reaction and at lower wavenumber and a few sunflower oil (green), burned the final stage, 45 minutes later, peaks appear in the C-H stretch sunflower oil and oven cleaner in addition to burned sunflower region, indicting an increase in mixture at 0 minutes (blue), burned oil before oven cleaner was the concentration of the sunflower oil and oven cleaner introduced. As time passes, the ingredients as the water mixture at 45 minutes (red). -1 O-H band in the 3400-3500 cm evaporated. Note that there is no spectral range shifts from 3377 peak at 1558 cm-1 after the oven -1 -1 cm to 3384 cm and broadens cleaner dried, indicating that this 100 initially before decreasing in new peak that appeared after intensity, which is likely due to oven cleaner was deposited on 80
water evaporating from the oven burned sun flower oil is likely 60
cleaner. The presence of an carboxylate salt of fatty acids, a Transmittance [%] alcohol is at 45 minutes as a product of the reaction between 40 result of sodium hydroxide oven cleaner and burned 3500 3000 2500 2000 1500 1000 500 hydrolyzing the triglycerides. sunflower oil. W avenumber cm-1 There are no significant changes Figure 5. A comparison of the ATR to the C-H stretch peaks in the CONCLUSION spectra of burned sunflower oil and 3000-2850 cm-1 spectral range. oven cleaner mixture at 45 minutes The DiaMaxATR accessory (green) and oven cleaner drying at 45 The ester carbonyl group at 1740 is extremely useful in analyzing -1 minutes (pink). cm decreased upon the samples such as harsh and introduction of oven cleaner, and corrosive cleaning agents, such a new peak appeared at 1558 -1 as oven cleaner and its reaction cm , which is likely the with potential contact materials, presence of carboxylate salt of such as oils, grease, and other fatty acids. The peak at 1558 cm- 1 burned food products found on increased in intensity as the oven surfaces. reaction progressed, which indicates a saponification reaction likely occurred either partially or fully. In figure 5, a spectrum of