scholarly journals Synthesis of non-phosphorylated epoxidised corn oil as a novel green flame retardant thermoset resin

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maurelio Cabo ◽  
Prabhakar M. N. ◽  
Jung-il Song
Keyword(s):  
Flame Retardant ◽  
Corn Oil ◽  
Heat Rate ◽  
Proton Nuclear Magnetic Resonance ◽  
Attenuated Total Reflectance ◽  
One Pot ◽  
Mass Selective Detector ◽  
Thermoset Resin ◽  
Selective Detector ◽  
Percentage Conversion

AbstractThis study aimed to produce a new potential flame retardant thermoset resin from epoxidised corn oil through a one-pot method using liquid inorganic catalysed with hydrogen peroxide. Using a gas chromatography–mass selective detector, attenuated total reflectance-fourier transform infrared spectroscopy, proton nuclear magnetic resonance imaging, optical microscopy, and scanning emission microscopy, we synthesised a bio-based resin based on newly designed parameters. The flame retardant capacity was fully established using thermogravimetric analysis and a micro calorimeter. The produced epoxidised corn oil had a relative percentage conversion of oxirane of approximately 91.70%, wherein the amount of double bonds converted into epoxides was calculated. A significant reduction from 17 to 40% in peak heat rate release (pHRR) and 26–30% in total heat release was observed, confirming its flame retardant property. Thus, the potential of epoxidised corn oil was demonstrated.

scholarly journals One-Pot Synthesis of 7, 7-Dimethyl-4-Phenyl-2-Thioxo-2,3,4,6,7, 8-Hexahydro-1H-Quinazoline-5-OnesUsing Zinc Ferrite Nanocatalyst and Its Bio Evaluation

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 431
Author(s):  
Tentu Nageswara Rao ◽  
Nalla Krishnarao ◽  
Faheem Ahmed ◽  
Suliman Yousef Alomar ◽  
Fadwa Albalawi ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Zinc Ferrite ◽  
Large Scale ◽  
Cyano Group ◽  
Proton Nuclear Magnetic Resonance ◽  
Scale Production ◽  
One Pot ◽  
Antibacterial And Antifungal ◽  
Nuclear Magnetic

A simple and highly efficient protocol for the synthesis of derivatives 7, 7-dimethyl-4-phenyl-2-thioxo-2, 3, 4, 6, 7, 8-hexahydro-1H-quinazoline-5-one from 5, 5-dimethyl cyclohexane-1, 3-dione (4a–4h) (dimedone) has been described. The aryl aldehydes were substituted with thiourea in the presence of synthesized zinc ferrite nanocatalyst, which increased the yield under reflux through condensation, followed by cyclization to give desired products. The other advantages are that it is eco-friendly and economically affordable for large-scale production. Structural validation and characterization of all the newly synthesized compounds were evaluated by spectral analysis (mass spectrometry, proton nuclear magnetic resonance (1HNMR), and Carbon-13 nuclear magnetic resonance(13CNMR)spectroscopies. The structure of antibacterial and antifungal assays was performed with the newly synthesized compounds. The antimicrobial activity of title compounds possessing electron-withdrawing groups such as (4e–4h) (Cl, Br, and cyano group) exhibited more active potential than the electron-donating groups, C6H5,4-C6H4, 3-OC2H5-4OH-C6H3, etc., (4a–4d) containing moiety.

scholarly journals Application of chromato-mass-spectrometric methods of determination of exposure markers in biomonitoring researches in workers of productions of polyvinyl chloride and aluminum

2020 ◽  
Vol 99 (10) ◽  
pp. 1159-1164
Author(s):  
Salim F. Shayakhmetov ◽  
Olga M. Zhurba ◽  
Anton N. Alekseenko ◽  
Alexey V. Merinov
Keyword(s):  
Polyvinyl Chloride ◽  
Mass Spectrometric ◽  
Aluminum Production ◽  
Control Groups ◽  
Biological Media ◽  
Mass Selective Detector ◽  
Selective Detector ◽  
Highly Sensitive ◽  
Polycyclic Aromatic

Introduction. The presence of highly toxic polycyclic aromatic hydrocarbons (PAHs) in the production of aluminum and organochlorine compounds (OCC) in the production of polyvinyl chloride (PVC) poses a serious threat to the health of workers, necessitates biological monitoring of toxicants and their metabolites in biological media to assess health risks on basis of modern methods chemical analysis. Material and methods. Biomonitoring studies of the content of marker metabolite OCC - thiodiacetic acid (TDAA) in urine were performed in 65 workers of PVC production and PAHs metabolite - 1-hydroxypyrene (1-OHPyr) in 144 workers of the aluminum smelter using developed own methods of gas-chromato-mass-spectrometric (GC-MS) analysis. Sample analysis was performed on an Agilent 7890A gas chromatograph with an Agilent 5979 mass selective detector. Results. Methodological methods and parameters of GC-MS measurement of TDAA and 1-OHPyr in urine, which provided high selectivity and sensitivity of the analysis of samples, were examined and considered. Reliable differences in the levels of marker metabolites among the groups of main and auxiliary occupations and persons in the control groups, their dependence on the degree of exposure to PAHs, and OCC were established. The highest concentrations of TDAA in urine were observed in unit operators of PVC workshop and 1-OHPyr - in anode workers of aluminum production. Discussion. The revealed reliable intergroup and interindividual differences in the contents of TDAA and 1-OHPyr in the urine of workers indicate the reliability and informativeness of the results of the analysis of biological media. The results are consistent with data from foreign studies, confirm the occupational - production nature of the exposure of toxicants among workers in the main professions of enterprises. Conclusion. The results of approbation of highly sensitive and selective methods for the determination of TDAA and 1-OHPyr in urine samples developed on the base of GC-MS method demonstrate the possibility of their use in biomonitoring studies of workers of productions and the population to adequately assess the exposure of highly toxic PAHs and OCC.

scholarly journals Determina tion of diacetyl and 2,3-pentanedione in beer by gc/ms using solid-phase extraction columns

2002 ◽  
pp. 45-54 ◽  
Author(s):  
Jelena Pejin ◽  
Olgica Grujic ◽  
Nikola Marjanovic ◽  
Djura Vujic ◽  
Suncica Kocic-Tanackov
Keyword(s):  
Gas Chromatography ◽  
Solid Phase Extraction ◽  
Simultaneous Determination ◽  
Solid Phase ◽  
Phase Extraction ◽  
Mass Selective Detector ◽  
Selective Detector

A new GC/MS method for the determination of diacetyl and 2,3-pentanedione was investigated. Diacetyl and 2,3-pentanedione were derivatized with 1,2-diaminobenzene to form 2,3-dimetylquinoxaline and 2-ethyl-3-methylquinoxaline. respectively. The amounts of formed 2.3-dimetylqu:inoxaline and 2-ethyl-3,.methylquinoxaline were proportional to the concentrations of diacetyl and 2,3-penianedione present in the sample. 2,3-Dimetylquinoxaline and 2-ethyl-3-methylquinoxaline were extracted by solid-phase extraction (SPE) columns and determined by gas chromatography using a mass selective detector. This method was applied for the determination of diacetyl and 2,3-pentanedione concentrations in beer. Extraction by SPE columns proved to be very simple and reliable. The method can be used for simultaneous determination of diacetyl and 2,3-pentanedione concentrations in beer in a great number of beer samples.

scholarly journals Excretion of ropivacaine with breast milk during prolonged analgesia of a postoperative wound

2021 ◽  
Vol 14 (3) ◽  
pp. 149-155
Author(s):  
А. А. Vinokurova ◽  
M. A. Hofenberg ◽  
V. A. Bagin ◽  
S. G. Dubrovin ◽  
V. A. Rudnov
Keyword(s):  
Breast Milk ◽  
Continuous Infusion ◽  
Spinal Anesthesia ◽  
Infectious Complications ◽  
Loading Dose ◽  
Wound Infiltration ◽  
Mass Selective Detector ◽  
Number Of Patients ◽  
Selective Detector ◽  
The Mean

The aimof our study was to evaluate the safety of ropivacaine given to lactating patients as a continuous infusion according to the selected local continuous wound infiltration (CWI) protocol after cesarean section (CS). Materials and methods.Elective CSs were performed under spinal anesthesia with bupivacaine 5% -2 ml at the L2L3 level. At the end of the operation, a 22 cm multiperforated catheter was placed in the surgical wound under the aponeurosis. 3 hours after spinal anesthesia a loading dose 8 ml of 0.2% ropivacaine was administered and followed by continuous infusion at rate 4 mL/h for 48 hours. Aside from CWI, all patients received systemic anesthesia: acetaminophen 4000 mg per os, ketorolac 90 mg IV and rescue opioid tramadol up to 400 mg (as-needed) daily. Breast milk (colostrum) samples were collected after 24 and 48 hours after a loading dose and were analyzed by gas chromatography with a mass selective detector for total ropivacaine concentrations. Results.The number of patients included in the study was 8. During the study neither cases of the onset of symptoms associated with systemic toxicity of ropivacaine, nor allergic and infectious complications, were observed. The mean +- SD Cmax total colostrum ropivacaine concentration was 0.005 0.002 (0.002 0.007) g / ml. Conclusion.In this limited sample, increasing the concentration or/and infusion rate seems to be a safe (for both mother and newborn) alternative or adjunct to standard systemic analgesia after CS in order to provide proper postoperative pain control.

Synthesis of a phosphorus–nitrogen-containing flame retardant and its application in epoxy resin

2018 ◽  
Vol 31 (2) ◽  
pp. 186-196 ◽  
Author(s):  
Shuang Yang ◽  
Yefa Hu ◽  
Qiaoxin Zhang
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Heat Release Rate ◽  
Flame Retardancy ◽  
Release Rate ◽  
Epoxy Resins ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Cone Calorimeter Test

In this article, a phosphorus–nitrogen-containing flame retardant (DOPO-T) was successfully synthesized by nucleophilic substitution reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and cyanuric chloride. The chemical structure of DOPO-T was characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance (NMR) and phosphorous-31 NMR, and elemental analysis. DOPO-T was then blended with diglycidyl ether of bisphenol-A to prepare flame-retardant epoxy resins. Thermal properties, flame retardancy, and combustion behavior of the cured epoxy resins were evaluated by differential scanning calorimetry, thermogravimetric analysis, limited oxygen index (LOI) measurement, UL94 vertical burning test, and cone calorimeter test. The results indicated that the glass transition temperature ( Tg) and temperature at 5% weight loss of epoxy resin (EP)/DOPO-T thermosets were gradually decreased with the increasing content of DOPO-T. DOPO-T catalyzed the decomposition of EP matrix in advance. The flame-retardant performance of EP thermosets was significantly enhanced with the addition of DOPO-T. EP/DOPO-T-0.9 sample had an LOI value of 36.2% and achieved UL94 V-1 rating. In addition, the average of heat release rate, peak of heat release rate, average of effective heat of combustion, and total heat release (THR) of EP/DOPO-T-0.9 sample were decreased by 32%, 48%, 23%, and 31%, respectively, compared with the neat EP sample. Impressively, EP/DOPO-T thermosets acquired excellent flame retardancy under low loading of flame retardant.

Flame-retardant behaviors of aluminum phosphates coated sepiolite in epoxy resin

2020 ◽  
pp. 073490412093408
Author(s):  
Wei Yan ◽  
Pu Xie ◽  
Zhengwei Yang ◽  
Guangjin Luo ◽  
Weijiang Huang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Mechanical Performance ◽  
Oxygen Index ◽  
One Pot ◽  
Heterogeneous Precipitation ◽  
Aluminum Phosphates ◽  
Thermal Stability Of ◽  
Limited Oxygen

Aluminum phosphates coated sepiolite nanocomposite was fabricated via a simple one-pot heterogeneous precipitation strategy, and the effects of aluminum phosphates on the morphology of aluminum phosphates coated sepiolite were investigated. Moreover, the effect of aluminum phosphates coated sepiolite on the flame-retardant behavior, mechanical properties, and thermal stability of epoxy resin have been discussed. The results indicated that the introduction of only 20 wt% aluminum phosphates coated sepiolite in epoxy resin increased the limited oxygen index from 21.8% to 30.1%, thus the material met the UL-94 V-0 rating. Thermogravimetric analyses revealed that char yield increased in the presence of aluminum phosphates coated sepiolite form thermally stable carbonaceous char. Aluminum phosphates–coated sepiolite could improve the mechanical performance, thermal stability of epoxy resin.

scholarly journals Optimal Extraction of Ocimum basilicum Essential Oil by Association of Ultrasound and Hydrodistillation and Its Potential as a Biopesticide Against a Major Stored Grains Pest

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2781 ◽  
Author(s):  
Eridiane da Silva Moura ◽  
Lêda Rita D’Antonino Faroni ◽  
Fernanda Fernandes Heleno ◽  
Alessandra Aparecida Zinato Rodrigues ◽  
Lucas Henrique Figueiredo Prates ◽  
...  
Keyword(s):  
Biological Activity ◽  
Essential Oil ◽  
Insect Pests ◽  
Extraction Process ◽  
Ocimum Basilicum ◽  
Gas Chromatograph ◽  
Drying Temperature ◽  
Mass Selective Detector ◽  
Potential Control ◽  
Selective Detector

The essential oil of basil (Ocimum basilicum) has significant biological activity against insect pests and can be extracted through various techniques. This work aimed to optimize and validate the extraction process of the essential oil of O. basilicum submitted to different drying temperatures of the leaves and extracted by the combination of a Clevenger method and ultrasound. The biological activity of the extracted oil under different conditions was evaluated for potential control of Sitophilus zeamais. The extraction method was optimized according to the sonication time by ultrasound (0, 8, 19, 31 and 38 min) and hydrodistillation (20, 30, 45, 60 and 70 min) and drying temperature (20, 30, 45, 60 and 70 °C). The bioactivity of the essential oil was assessed against adults of S. zeamais and the effects of each variable and its interactions on the mortality of the insects were evaluated. The best yield of essential oil was obtained with the longest sonication and hydrodistillation times and the lowest drying temperature of leaves. Higher toxicity of the essential oil against S. zeamais was obtained by the use of ultrasound for its extraction. The identification and the relative percentage of the compounds of the essential oil were performed with a gas chromatograph coupled to a mass selective detector. The performance of the method was assessed by studying selectivity, linearity, limits of detection (LOD) and quantification (LOQ), precision and accuracy. The LOD and LOQ values for linalool were 2.19 and 6.62 µg mL−1 and for estragole 2.001 and 6.063 µg mL−1, respectively. The coefficients of determination (R2) were >0.99. The average recoveries ranged between 71 and 106%, with coefficient of variation ≤6.4%.

Sign in / Sign up

Export Citation Format

Share Document