Features of formation somatic pathologies under chronic exposure to hydrofluoride in the manufacture of titanic alloys

Introduction. Most studies on the morbidity of workers with fluorine compounds are devoted to occupational medicine at aluminium industry enterprises. The aim of the study is to identify the exposure, gender and evolutionary features of the formation of general somatic morbidity associated with chronic occupational exposure to hydrofluoride in the production of titanium alloys. Materials and methods. The analysis of the prevalence of chronic pathology according to the medical examination of 562 workers in contact with hydrofluoride and the incidence of temporary disability according to 29949 disability sheets in comparison with non-exposed persons of the same enterprise is given. Results. With an increase in the degree of harmfulness of working conditions, there was an augmentation increase in the risk of developing pathology of the respiratory organs, eyes, musculoskeletal system, arterial hypertension and hypercholesterolemia. In the working conditions of Class 3.1, an increased prevalence of diseases of the nervous and genitourinary systems with a moderate degree of occupational conditionality was revealed (relative risks (RR) 1.6 and 2.0, respectively, р < 0.05), class 3.2 - a high degree of professional conditionality of respiratory diseases (RR = 2.8). When working in harmful working conditions, there was an average degree of occupational conditionality of nervous system diseases in women (RR = 1.9) and a small degree of arterial hypertension in men (RR = 1.2). The prevalence of general somatic pathology in all age groups was higher than in non-exposed persons of the same age. Conclusion. Hydrofluoride in the production of titanium alloys was proved to be a trigger contributing to the formation of the pathology of the respiratory, circulatory, digestive, ear, eyes, skin, blood, musculoskeletal, nervous, endocrine, and genitourinary systems.

Biomimetic enantioselective synthesis of β,β-difluoro-α-amino acid derivatives

Although utilization of fluorine compounds has a long history, synthesis of chiral fluorinated amino acid derivatives with structural diversity and high stereoselectivity is still very appealing and challenging. Here, we report a biomimetic study of enantioselective [1,3]-proton shift of β,β-difluoro-α-imine amides catalyzed by chiral quinine derivatives. A wide range of corresponding β,β-difluoro-α-amino amides were achieved in good yields with high enantioselectivities. The optically pure β,β-difluoro-α-amino acid derivatives were further obtained, which have high application values in the synthesis of fluoro peptides, fluoro amino alcohols and other valuable fluorine-containing molecules.

Study of the content of fluorides in atmospheric air in Bokhtar region and Tursunzade city of Tajikistan

Background: The emission and presence of air pollutants such as fluorides has over burdenized the public healthcare issues. The current study aimed to determine the content of fluorides in atmospheric air in Bokhtar region and Tursunzade city of Tajikistan. Methods: Based on the direction of wind, two zones were selected in the current study: experimental and control. In the first (experimental) zone, those areas were selected where the western, northern and northeastern directions of wind was significant. Dzhura Rakhmonov was assigned to the control zone with the shortest time for the eastward winds. In general, 72 samples of atmospheric air were taken in 12 settlements of the city of Tursunzade and 90 samples of atmospheric air in the Bokhtar region of the Khatlon province. To determine fluorine in air, a potentiometric method with an ion-selective electrode was used, which makes it possible to measure the potential concentrations of fluorides in atmospheric air. Results: Compounds of gaseous (hydrogen fluoride) and solid fluorine (salts of hydrofluoric acid), which are the main emission from various sources, were found in the atmospheric air of the populated areas of the city of Tursunzade, where the aluminum plant industry is located. The maximum amount of hydrogen fluoride in the experimental zone (Jamoat and Navobod) with a western wind direction was found in the autumn, which exceeded the MPC. However, the amount of solid fluorides in the western direction of the wind ranged from 0.01 to 1.0 mg / m3, which did not exceed the MPC value and was not significant. In control zone (Dzhura Rakhmonov) the said pollutants hydrogen fluoride and solid fluorine were not significant in autumn within accordance to MPC limit. The results of the study of atmospheric air in 15 administrative cities and districts of the Bokhtar region showed a complete absence of solid fluorides in all samples of atmospheric air. Conclusion: Compounds of gaseous fluorine and salts of hydrofluoric acid were found in the atmospheric air of populated areas of the city of Tursunzade, and no significant amounts in the Bokhtar region according to MPC and control. The maximum amount of fluorine compounds was found in the experimental zone (Jamoat Navobod) of the city of Tursunzade.

Avalanche effect for chemically modified dust mitigation from surfaces

Cost effective dust mitigation from surfaces is one of the challenges in various sectors. The reduction of dust adhesion on surfaces plays a vital role for dust mitigation from surfaces under the gravitational influence. Creating an avalanche effect on dusty surfaces improves the dust mitigation rate and provides an effective cleaning process. Hence, solution treatment of dust by low concentration hydrofluoric acid is considered towards reducing dust adhesion on glass surfaces. To increase the rate of dust mitigation, the avalanche influence is created by the higher density and larger size particles (5300 kg/m3 and ~ 50 µm) than the average size dust particles (2800 kg/m3 and 1.2 µm) via locating them in the top region of the dusty glass surfaces. Mitigation velocity of the dust particles is evaluated using a high-speed recording system and the tracker program. Findings revealed that solution treatment (curing) of the dust particles results in the formation of fluorine compounds, such as CaF2 and MgF2, on dust surfaces, which suppress dust adhesion on surfaces. OSHA Globally Harmonized System lists the fluorine compounds formed as environmentally non-harmful. Avalanche's influence results in dust mitigation at a smaller tilt angle of the glass surface (~ 52°) than that of the case with none-avalanche influence (63°). Area cleaned on the glass surface, via dust mitigation, is larger as the avalanche is introduced, which becomes more apparent for the solution treated dust particles. Dust mitigation under avalanche influence improves optical transmittance of the dusty glass samples by a factor of 98%.

Optimization of Pickling Solution for Improving the Phosphatability of Advanced High-Strength Steels

This study investigated the optimum pickling conditions for improving the phosphatability of advanced high-strength steel (AHSS) using surface analysis and electrochemical measurements. To remove the SiO2 that forms on the surface of AHSS, 30 wt.% NH4HF2 was added to the pickling solution, resulting in a significant reduction in the amount of SiO2 remaining on the surface of the AHSS. The phosphatability was improved remarkably using HNO3 concentrations higher than 13% in the pickling solution. Furthermore, phosphate crystals became finer after pickling with a HNO3-based solution rather than a HCl-based solution. Electrochemical impedance spectroscopy (EIS) data indicated that the corrosion resistance of AHSS subjected to HNO3-based pickling was higher than that of AHSS subjected to HCl-based pickling. Fluorine compounds, which were involved in the phosphate treatment process, were only formed on the surface of steel in HNO3-based solutions. The F compounds reacted with the phosphate solution to increase the pH of the bulk solution, which greatly improved the phosphatability. The phosphatability was better under HNO3-based conditions than a HCl-based condition due to the fineness of the phosphate structure and the increased surface roughness.

Agroecological assessment of fluorine in soils and agricultural plants of steppe landscapes of Odessa region

The materials of long-term research of the features of the content and distribution of fluorine in southern chernozems are highlighted. The purpose of this work is to investigate the effects of irrigation and chemical meliorants on the fluorine accumulation in soils and crops. To achieve this goal, the following tasks were set: to determine the content of fluorine in soils and plants in conditions of irrigation and application of phosphorus fertilizers (phosphogypsum); to carry out ecological assessment of southern chernozems in terms of accumulation and migration of fluorine in soil, plant resistance to fluorine accumulationand translocation. The research was conducted within the irrigation areas of Odessa region. Bulk and movable forms of fluorine were determined by the potentiometric method in the southern chernozems of different reclamation state (non-irrigated, irrigated and irrigated reclaimed). The content of movable fluorine in agricultural plants was determined by the author’s method. It was established that the contest of bulk fluorine is the highest in the non-irrigated chernozems, but does not exceed the MPC. In irrigation, the number of bulk forms of fluorine decreases due to their dissolution and migration from the top layer to the depth of the soil profile. The content of soluble forms of fluorine increases significantly in all components of agrolandscape under the influence of irrigation and especially the introduction of phosphogypsum. It was determined that the combined application of phosphorous fertilizers and manure leads toa decrease of the fluorine content in soils, lysimetric waters and agricultural plants. The degree of mobility of fluorine compounds in the studied chernozems during irrigation and especially the introduction of phosphogypsum increases. The level of fluorine content in lysimetric waters and the coefficient of water migration correlate with its content in soils. A positive correlation was found between the fluorine content in the roots of maize, oats, wheat ear and soil while its absence between the content of fluorine in the stems and leaves. The introduction of mineral and organic fertilizers together enhances the ability of plants to absorb fluorine from chernozem soils. The active contamination rate for all tested plants is higher than one, which can cause their inhibition. When resuming irrigation of chernozem soils, there will be a need for increased doses of mineral, including phosphorus fertilizers. Despite the low solubility of fluorine compounds, conducted research has shown that irrigation and application of phosphogypsum significantly increases the soluble forms of fluorine, which can adversely affect the pollution of agrolandscapes and public health.