SỬ DỤNG TÍNH TOÁN DFT KẾT HỢP VỚI THỰC NGHIỆM ĐỂ XÁC ĐỊNH CÁC ĐẶC TÍNH CỦA BENZOYL PEROXID

Hoạt chất benzoyl peroxid được sử dụng bôi ngoài da để điều trị mụn trứng cá, tiêu sừng và chống viêm. Kết quả quang phổ Raman, IR thu được từ thực nghiệm được so sánh với các tính toán lượng tử Gaussian với DFT/B3LYP kết hợp với các tiêu chuẩn 6-311+G(d,p). Các đặc tính lý hóa và đặc tính dược lực của phân tử hữu cơ benzoyl peroxide đã được phân tích bằng quang phổ IR, Raman. Vị trí số sóng đặc trưng của các liên kết, các nhóm trong benzoyl peroxid đều bị lệch nhiều so với vị trí dải bước sóng thông thường. Phân tích điện Mulliken cho thấy các đám mây điện tử dẫn hướng qua carbon liên kết với nhóm peroxide của phân tử trên cùng của vòng benzen. Độ âm điện và thế hóa học của benzoyl peroxide có cùng độ lớn là 4,72955, cho các liên kết hóa học chặt chẽ và độ bền liên kết của electron cao.

Colorimetric Sensing of Benzoyl Peroxide Based on the Emission Wavelength-Shift of CsPbBr3 Perovskite Nanocrystals

Using the ionic salt characteristics of CsPbBr3 perovskite nanocrystals (CsPbBr3 NCs), the fluorescence wavelength of CsPbBr3−xIx NCs could be changed by the halogen exchange reaction between CsPbBr3 NCs and oleylammonium iodide (OLAM-I). Under the excitation of a 365 nm UV lamp and the increase of OLAM-I concentration, the content of iodine in CsPbBr3−xIx NCs increased, and the fluorescence emission wavelength showed a redshift from 511.6 nm to 593.4 nm, resulting in the fluorescence color change of CsPbBr3 NCs from green to orange-red. Since OLAM-I is a mild reducing agent and easily oxidized by benzoyl peroxide (BPO), a novel colorimetric sensing approach for BPO based on the fluorescence wavelength shift was established in this study. The linear relationship between the different wavelength shifts (Δλ) and the concentration of BPO (CBPO) is found to be in the range of 0 to 120 μmol L−1. The coefficient of alteration (R2) and the detection limit are 0.9933 and 0.13 μmol L−1 BPO, respectively. With this approach, the determination procedure of BPO in flour and noodle samples can be achieved in only a few minutes and exhibit high sensitivity and selectivity.

Preparation and characterization of liquid natural rubber through oxidative degradation with phenyl hydrazine and benzoyl peroxide-oxygen

The aim of this research was to synthesize liquid natural rubber (LNR) from Natural rubber (SIR-20) by chain scission method in the presence of oxygen gas and difference of peroxides, phenyl hydrazine and benzoyl peroxide. The chain scission reaction was conducted in solution of xylene in close system. SIR-20 was diluted xylene before flushing with oxygen and the addition of the peroxide. The degradation oxidation by the oxygen and the peroxides was processed at 60°C for 24 hours. The degradative oxidation product was re-precipitated by adding the excess of methanol and filtrated before dried in vacuum oven 60°C for 24 hours. The dried product was characterized by Fourier Transform Infra Red (FTIR). It was found that the liquid natural rubber product successfully degraded by chain scission process as shown the change of the peak area intensity of infrared absorption. It was showed the peaks area intensity of O-H and carbonyl group of liquid natural rubber spectra increased.

Functional groups of bio-lubricants from crude catfish oil (Pangasius hypothalamus)

Bio-lubricants have great potential in the production of lubricating in the future. Several studies have developed animal oils as lubricants, which come from a by-product of fish processing. Fish oil extracted from the material and processed into bio-lubricants reached the highest yield of 94%. This research aimed to study the bio-lubricants functional groups. The research steps extracted crude fish oil as raw material, hydrolysis using HCl catalyst, polymerization using benzoyl peroxide, and polyesterification using ethylene glycol. The extraction process used the wet rendering method with a ratio of catfish waste (viscera) to the water of 1:2 (w/v) at 70 °C for 30 minutes. The best bio-lubricants were analyzed for functional groups using an FT-IR instrument with a wave range of 4000-450 cm−1. The results obtained were the absorption wavelength peak of 3472 cm−1, indicating O-H bonds with the sloping peak and the weak bond. The absorption wave peak of 3006-2852 cm−1 indicated a strong C-H bond (alkane). The absorption wave peaks of 1743 cm−1 indicated the presence of a C=O double bond. The adsorption wave peaks at 1465 cm−1 indicated carbon chain bonds between C-C, while the absorption wave peaks at 1115 and 1174 cm−1 indicated C-O bonds. The three spectral indicated that the ester groups formed in bio-lubricants. In the polymerization reaction, there was no absorption wave of 1600-1500 cm−1 which indicated that all C=C groups had been polymerized by benzoyl peroxide. Meanwhile, a sloping absorption wave of 3472 cm−1 was found in the polyesterification reaction due to the weak O-H bond. The analysis obtained above showed the differences in wave peak between bio-lubricant and crude fish oil as raw material but had the same group shape.