scholarly journals Water Effect on Oxidative Desulphurization Process of Straight-Run Kerosene Fraction / Wpływ Wody Na Utleniający Proces Odsiarczania Frakcji Nafty

2013 ◽  
Vol 20 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Serhiy Pyshyev ◽  
Michael Bratychak ◽  
Vasyl Hayvanovych ◽  
Pavlo Paniv ◽  
Witold Wacławek
Keyword(s):  
Atmospheric Oxygen ◽  
Reaction Medium ◽  
Inhibitory Effect ◽  
Oxidation Products ◽  
Sulphur Compounds ◽  
Effect Of Water ◽  
Oxidative Desulphurization ◽  
Kerosene Fraction ◽  
Sulphur Recovery ◽  
In The Beginning

Abstract Sulphur dioxide obtained during fuels burning in combustion engines is one of the main pollutants. In diesel oils and gasolines the sulphur content must be 5-10 ppm and in jet fuels - 300-3000 ppm. However the production of hydrofined jet fuel is problematic. The reason is deterioration of fuel stability and antioxygenic properties. The oxidative desulphurization of straight-run kerosene was investigated. This method combines oxidation by atmospheric oxygen of sulphur compounds under increased temperature and pressure in the presence of water in the reaction medium, and removal of oxidized sulphur compounds from the oxidation-treated fuel via rectification. It was showed that water partially extracts from the hydrocarbon medium acidic compounds, formed in the beginning stage of oxidation, dissociation of which leads to the formation in water acidic medium. As a result, a pathway of the hydroperoxides decomposition partially changes from the formation of carbonic acids and oxyacids to the formation of alcohols, phenols and alkylphenols, which displayed an inhibitory effect in hydrocarbon oxidation. It was assumed that an inhibitory effect of water, in addition to the creation reverse micelles with peroxides and complexes with free radicals, caused by oxidation products created in the beginning stage of oxidation. The effect of water/kerosene ratio on the oxidative desulphurization of straight-run kerosene fraction has been examined. It was found that water improves process selectivity with insignificant influence on the degree of sulphur recovery. The optimum value of water/kerosene ratio for the fuel containing 0.15% mass of sulphuric compounds has been determined.

Comparative Studies on the Behaviour of Copper in Various Electrically Insulating Fluids

2018 ◽  
Vol 69 (8) ◽  
pp. 2029-2034
Author(s):  
Iosif Lingvay ◽  
Gabriela Oprina ◽  
Emilia Simona Apostol ◽  
Daniel Lipcinski ◽  
Ion Patru ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Morphological Changes ◽  
Atmospheric Oxygen ◽  
Direct Consequence ◽  
Oxidation Products ◽  
Copper Films ◽  
Sulphur Compounds ◽  
Mineral Oils ◽  
Closed Systems ◽  
Exhaustive Study

This paper presents an exhaustive study regarding the behaviour of copper in various insulating fluids when exposed to 1100C for 1000 hours in closed systems, with no access to atmospheric oxygen. Following the analysis carried out, it was found that the variation of oxygen concentration in the investigated oil samples, during the thermal treatment, may be best described using an exponential decrease versus time. Moreover, from the gas chromatography determinations with respect to the evolution of the CO and CO2 content in the oils during the thermal treatment one found out that these fit very well the Richards model, which corroborated with all the other analysis confirms the fact that the copper films undergo consistent morphological changes only when exposed to mineral oils, so that it is of paramount importance that, taking into account this aggressive character, the equipment placed in direct contact with these oils should be carefully inspected on a periodical basis. This behaviour is thought to be a direct consequence of the sulphur compounds contents for these oils, the secondary oxidation products of these compounds increasing their corrosive aggressiveness.

The phosphoenolpyruvate: sugar phosphotransferase system of Streptococcus salivarius. Identification of a IIIman protein

1987 ◽  
Vol 33 (2) ◽  
pp. 118-122 ◽  
Author(s):  
Christian Vadeboncoeur ◽  
Lucie Gauthier
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
Deae Cellulose ◽  
Reaction Medium ◽  
Inhibitory Effect ◽  
Spontaneous Mutant ◽  
Streptococcus Salivarius ◽  
Wild Type ◽  
Phosphotransferase System ◽  
Growth Inhibitory

A double-spontaneous mutant resistant to the growth inhibitory effect of α-methylglucoside and 2-deoxyglucose was isolated from Streptococcus salivarius. This mutant strain, called αS3L11, did not grow on mannose and grew poorly on 5 mM fructose and 5 mM glucose. Isolated membranes of strain αS3L11 were unable to catalyse the phosphoenolpyruvate-dependent phosphorylation of mannose in the presence of purified enzyme I and HPr. Addition of dialysed membrane-free cellular extract of the wild-type strain to the reaction medium restored the activity. The factor that restored the phosphoenolpyruvate–mannose phosphotransferase activity to membranes of strain αS3L11 was called IIIman. This factor was partially purified from the wild-type strain by DEAE-cellulose chromatography, DEAE-TSK chromatography, and molecular seiving on a column of Ultrogel AcA 34. This partially purified preparation also enhanced the phosphoenolpyruvate-dependent phosphorylation of glucose, fructose, and 2-deoxyglucose in strain αS3L11.

Catalytic combustion of styrene over copper based catalyst: Inhibitory effect of water vapor

Chemosphere ◽  
2009 ◽  
Vol 76 (5) ◽  
pp. 721-726 ◽  
Author(s):  
Hongyan Pan ◽  
Mingyao Xu ◽  
Zhong Li ◽  
Sisi Huang ◽  
Chun He
Keyword(s):  
Water Vapor ◽  
Catalytic Combustion ◽  
Inhibitory Effect ◽  
Effect Of Water ◽  
Copper Based Catalyst

scholarly journals Low-Temperature Esterification to Produce Oleic Acid-Based Wax Esters Catalyzed by 4-Dodecylbenzenesulfonic Acid

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1471
Author(s):  
Zhenzhen Li ◽  
Wei Liu ◽  
Guolong Yang
Keyword(s):  
Oleic Acid ◽  
Low Temperature ◽  
Inhibitory Effect ◽  
Wax Esters ◽  
Molar Ratio ◽  
Efficient Catalyst ◽  
Dodecylbenzenesulfonic Acid ◽  
Effect Of Water ◽  
Solvent Free Conditions ◽  
Increasing Temperature

Synthesized oleic acid-based wax esters (e.g., cetyl oleate), which can replace spermaceti oil or jojoba oil, have been widely used in the cosmetic, pharmaceutical and other industries. In this work, 4-dodecylbenzenesulfonic acid (DBSA) has been successfully used as an efficient catalyst to synthesize oleic acid-based wax esters through esterification at 40 °C under solvent-free conditions. A 93.6% conversion rate of cetyl alcohol was obtained under optimal conditions: 10 mol% DBSA, a molar ratio of 1.3:1 oleic acid to alcohol, a reaction temperature 40 °C and a reaction time of 4 h. The effect of water content on esterification was investigated, and it was found that the inhibitory effect of water decreased significantly with increasing temperature. Moreover, DBSA-catalyzed esterification could be applied in the production of various oleic acid-based wax esters and excellent conversion (>90%) to esters was obtained under such mild conditions. DBSA-catalyzed low-temperature esterification is an efficient method for the production of liquid wax esters.

scholarly journals Conversion of Oleic Acid into Azelaic and Pelargonic Acid by a Chemo-Enzymatic Route

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1882 ◽  
Author(s):  
Elisabetta Brenna ◽  
Danilo Colombo ◽  
Giuseppe Di Lecce ◽  
Francesco G. Gatti ◽  
Maria Chiara Ghezzi ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Azelaic Acid ◽  
Atmospheric Oxygen ◽  
Reaction Medium ◽  
Chemical Oxidation ◽  
Pelargonic Acid ◽  
Dihydroxystearic Acid ◽  
Chemical Purity ◽  
Enzymatic Route

A chemo-enzymatic approach for the conversion of oleic acid into azelaic and pelargonic acid is herein described. It represents a sustainable alternative to ozonolysis, currently employed at the industrial scale to perform the reaction. Azelaic acid is produced in high chemical purity in 44% isolation yield after three steps, avoiding column chromatography purifications. In the first step, the lipase-mediated generation of peroleic acid in the presence of 35% H2O2 is employed for the self-epoxidation of the unsaturated acid to the corresponding oxirane derivative. This intermediate is submitted to in situ acid-catalyzed opening, to afford 9,10-dihydroxystearic acid, which readily crystallizes from the reaction medium. The chemical oxidation of the diol derivative, using atmospheric oxygen as a stoichiometric oxidant with catalytic quantities of Fe(NO3)3∙9∙H2O, (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), and NaCl, affords 9,10-dioxostearic acid which is cleaved by the action of 35% H2O2 in mild conditions, without requiring any catalyst, to give pelargonic and azelaic acid.

Oxidation of nonylphenol ethoxylates in aqueous solution by UV-C photolysis, H2O2/UV-C, Fenton and photo-Fenton processes: are these processes toxicologically safe?

2013 ◽  
Vol 68 (8) ◽  
pp. 1801-1809 ◽  
Author(s):  
Akin Karci ◽  
Idil Arslan-Alaton ◽  
Miray Bekbolet
Keyword(s):  
Acute Toxicity ◽  
Vibrio Fischeri ◽  
Degradation Products ◽  
Inhibitory Effect ◽  
Oxidation Products ◽  
Treatment Processes ◽  
Nonylphenol Polyethoxylate ◽  
Uv C ◽  
Toxicity Pattern ◽  
Oxalic Acids

UV-C, H2O2/UV-C, Fenton and photo-Fenton treatment of a nonylphenol polyethoxylate (NP-10) were comparatively studied, primarily focusing on the acute toxicity of degradation products. Formic, acetic and oxalic acids were all identified as the degradation products of NP-10; however, the sole common carboxylic acid was found to be formic acid for the studied treatment processes. The percent relative inhibition towards Vibrio fischeri increased from 9% to 33% and 24% after 120 min-UV-C and H2O2/UV-C treatment, respectively. Complete NP-10 and 70% of its total organic carbon (TOC) content was removed by the photo-Fenton process, which ensured the fastest removal rates and lowest inhibitory effect (8% after 120 min treatment). The acute toxicity pattern being observed during H2O2/UV-C and photo-Fenton treatment positively correlated with temporal evolution of the identified carboxylic acids, whereas unidentified oxidation products were the most likely origin of the acute toxicity in UV-C photolysis.

The Effect of Water Vapour and Sulphur on Corrosion Mechanisms of Steels

2008 ◽  
Vol 595-598 ◽  
pp. 841-849
Author(s):  
Satu Tuurna ◽  
Sanni Yli-Olli ◽  
Liisa Heikinheimo
Keyword(s):  
Water Vapour ◽  
Metal Surface ◽  
Corrosion Mechanism ◽  
Sulphur Compounds ◽  
Boiler Furnace ◽  
Effect Of Water ◽  
Kraft Recovery Boilers ◽  
Recovery Boilers ◽  
Corrosion Mechanisms ◽  
Test Atmosphere

It is well known that water vapour accelerates oxidation; however different gas conditions and material compositions affect the mechanism. The paper addresses this issue from two different application areas; biomass and kraft recovery boilers. In these applications water vapour and sulphur are simultaneously affecting the corrosion mechanism, though the mechanisms are different. Low-alloyed steels were exposed to an atmosphere containing different amounts of water vapour at temperatures of 420, 550 and 600°C. Under oxidising conditions increasing water content generally accelerates oxidation. However, presence of SO2 in moist atmosphere retards oxidation at high temperatures. The phenomenon is seen at low temperatures with higher chromium contents. Stainless steel 304L was tested in an atmosphere containing hydrogen sulphide and carbon monoxide with and without water vapour at a temperature of 440°C to simulate elevated kraft recovery boiler furnace conditions. The tests showed that water vapour in the test atmosphere produces a protective spinel oxide on the metal surface. In tests without water vapour, the initial scales at metal surface were different sulphur compounds and intensive sulphidation occurred. The effect of water vapour on the sulphidation mechanism is addressed in the paper through the described tests and thermodynamic modelling.

scholarly journals Litter Decomposition in a Semiarid Dune Grassland: Neutral Effect of Water Supply and Inhibitory Effect of Nitrogen Addition

PLoS ONE ◽  
2016 ◽  
Vol 11 (9) ◽  
pp. e0162663 ◽  
Author(s):  
Yulin Li ◽  
Zhiying Ning ◽  
Duo Cui ◽  
Wei Mao ◽  
Jingdong Bi ◽  
...  
Keyword(s):  
Water Supply ◽  
Litter Decomposition ◽  
Nitrogen Addition ◽  
Inhibitory Effect ◽  
Effect Of Water ◽  
Dune Grassland ◽  
Neutral Effect
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