High Molecular Organic Compounds Research Articles

Nonsteady-state mathematical modelling of H2SO4-catalysed alkylation of isobutane with alkenes

H2SO4-catalysed isobutane alkylation with alkenes is an important industrial process used to obtain high-octane alkylate. In this process, the concentration of H2SO4 is one of the main parameters. For alkylation, sulphuric acid containing 88%–98% monohydrate is typically used. However, only a H2SO4 concentration of 95%–96% enables alkylate with the maximum octane number to be obtained. Changes in H2SO4 concentration due to decontamination are the main cause of process variations. Therefore, it is necessary to maintain the reactor acid concentration at a constant level by regulating the supply of fresh catalyst and pumping out any spent acid. The main reasons for the decrease in the H2SO4 concentration are accumulation of high-molecular organic compounds and dilution by water. One way to improve and predict unsteady alkylation processes is to develop a mathematical model that considers catalyst deactivation. In the present work, the formation reactions of undesired substances were used in the description of the alkylation process, indicating the sensitivity of the prediction to H2SO4 activity variations. This was used for calculation the optimal technological modes ensuring the maximum selectivity and stability of the chemical–technological system under varying hydrocarbon feedstock compositions.

Interactions of Cationic and Anionic Dyes with Activated Carbons

Five kinds of activated carbon (AC1, AC2, AC3, AC4, and AC5) were prepared, and the characteristics (scanning electron microscopy images, specific surface area, pore-volume, pHpzc, surface functional groups, and surface hydroxyl groups) of each activated carbon were investigated. Additionally, the adsorption capability of activated carbons and adsorption mechanisms involved in adsorption of cationic and anionic dyes from the aqueous solution were evaluated. The results suggested that the treatment of activated carbon with silver (AC3), titanium oxide (AC4), or magnetic field (AC5) was not useful for increasing specific surface area and micropore volume. Moreover, the amount of cationic and anionic dyes adsorbed using activated carbon prepared from coconut shells (AC1 and AC2) were higher than that adsorbed using AC3, AC4, and AC5. Subsequently, the adsorption mechanism involved in adsorption of cationic and anionic dyes was also assessed. It was found that the amount of cationic and anionic dyes adsorbed was related to the specific surface area, micropore volume, and acidic or basic functional groups. Finally, the interactions between dyes and AC1 were elucidated in this study. Adsorption of dyes onto the AC1 surface was confirmed by the elemental distribution and X-ray photoelectron spectroscopy analysis. These results provide useful information on the surface interactions between the activated carbon and dyes (high molecular organic compounds).

Organic Matter Transformation in the Conjugate Series of Surface Water in Northern Karelia

The composition of organic matter in the conjugated series of natural water (soil, bog, creek, and lake water) has been considered. The composition of aliphatic and aromatic carboxylic acids and humic substances has been determined. Humic substances have been found to account for the major portion of dissolved organic carbon (from 28 in lake water to 57% in bog water with weight-averaged molecular masses of the order of 1 kDa); and the amounts of aliphatic and aromatic carboxylic acids, to account for ≤2% of the total concentration of carbon of water-soluble organic compounds. Transformation of dissolved organic matter have been shown to take place in the series of the examined water: the composition and its characteristics have been shown to change; and the share of the fraction with molecular mass <1 kDa, to increase because of photo- and biodegradation of high-molecular organic compounds.

Pilot-scale study on catalytic ozonation of bio-treated dyeing and finishing wastewater using recycled waste iron shavings as a catalyst

A pilot scale reactor with an effective volume of 2.93 m3 was built in-situ and run in both batch and continuous modes to investigate the removal for organic pollutants in bio-treated dyeing and finishing wastewater by heterogeneous catalytic ozonation under neutral pH with waste iron shavings as a catalyst. Experimental results showed that both running modes were able to reduce the chemical oxygen demand (COD) from 132–148 mg/L to a level below the discharge criteria (<80 mg/L) within 15–30 mins under several conditions. Specifically, significantly organic removal was observed with COD, soluble COD (sCOD) and dissolved organic carbon (DOC) decreased from the initial 165, 93 and 76 mg/L to 54, 28 and 16 mg/L respectively, when treated by 10.2 g-O3/min of ozone dosage at a hydraulic retention time of 30 mins under continuous mode. 80% proteins and 85% polysaccharides were removed with a decrease in their contribution to sCOD from 69% to 43%. Mineralization as well as conversion of high molecular organic compounds was observed through Gas Chromatography-Mass Spectrometer (GC-MS) & Liquid Chromatography-Mass Spectrometer (LC-MS) analysis, which led to a decrease of inhibitory effect from 29% to 25%, suggesting a reduction in the acute toxicity.

Development of composite membrane materials for fuel cells

This study is devoted to the development and investigation of composite membrane materials for fuel cells. Proton conductive membranes consisting of silica and various low- and high-molecular organic compounds have been prepared by the sol-gel method. The synthesized membranes are characterized by proton conductivity (up to 10-2 S/cm), ion-exchange capacity (1.84-3.5 meq/g), thermal stability (260 – 400 °C), and tensile modulus (128 - 322 MPa).

Simulation of the high-octane alkylates manufacturing considering the process unsteadiness

ABSTRACTThe aim of this paper work is to study the model of the process of sulphuric-acid alkylation of isobutane using a mathematical model. The model of the object was developed considering the physicochemical regularities of the process. The paper analyzes the main processes occurring at the installation and performs the results of model verification. In addition, the technological scheme of one of the sulphuric-acid alkylation existing installations were considered. The developed program is able to calculate the composition of the obtained alkylate, to determine the yield of target products and by-products, to select optimal technological process conditions for a given raw material composition. It was noted, that the consumption of sulfuric acid increases as a result of the accumulation of high-molecular organic compounds in it, as well as its dilution with water, which enters the reactor along with the raw material and forms during the side reactions of the process.

Influence of Inorganic Ions and Organic Substances on the Degradation of Pharmaceutical Compound in Water Matrix

The paper determined the influence of inorganic substances and high-molecular organic compounds on the decomposition of diclofenac, ibuprofen, and carbamazepine in the process of photocatalysis conducted with the presence of Titanium dioxide (TiO2). It was determined that the presence of such ions as CO 3 2 − , HCO 3 − , HPO 4 2 − as well as SO 4 2 − inhibited the decomposition of carbamazepine, whereas the efficiency of diclofenac degradation was decreased only by the presence of CO 3 2 − and HCO 3 − anions. In case of ibuprofen sodium salt (IBU), all investigated anions influenced the increase in its decomposition rate. The process of pharmaceutical photooxidation conducted in suspensions with Al3+ and Fe3+ cations was characterized by a significantly decreased efficiency when compared to the solution deprived of inorganic compounds. The addition of Ca2+, Mg2+ and NH4+ affected the increase of reaction rate constant value of diclofenac and ibuprofen decomposition. On the other hand, high molecular organic compounds present in the model effluent additionally catalysed the degradation process of pharmaceutical compounds and constituted an additional sorbent that enabled to decrease their concentration. Toxicological analysis conducted in deionized water with pharmaceutical compounds’ patterns proved the production of by-products from oxidation and/or reduction of micropollutants, which was not observed for model effluent irradiation.

Change of seawater fluorescence properties when mixing with crude oil

The fluorescence features of seawater with dissolved crude oil components during continuous 13-day mixing of water and oil are considered. Four specific fluorescence peaks are identified. Two of them are connected with polyaromatic hydrocarbons, and two other peaks, with high-molecular organic compounds. It is shown that the fluorescence spectrum of dissolved components of crude oil is not constant. Spectral features suitable for identification of dissolved crude oil in seawater are distinguished.

Новая технологическая схема очистки сточных вод с высокой концентрацией органических загрязнителей

This work is directed on search of new scientific and technological approaches to the solution of a problem related to ecological safety ensuring of modern productions of the vital biochemical substances and preparations. Results of pilot studies of the new technological scheme related to sewage treatment from high-molecular organic compounds of a natural and artificial origin with use of combined methods including reagent technologies, filtration and liquid-phase photo oxidizing process of pollution destruction under influence of high-intensity pulse optical radiation of constant spectrum have been presented. Optimum limits of each method’s applicability have been defined and the technological scheme of sewage treatment with high concentration of organic pollution for application on biochemical and pharmaceutical productions has been offered.

Metal Grinding in the Presence of Mechanically Degradable Polymer

Grinding of metal swarf in the presence of a mechanically degradable high-molecular compound intensifies the size-reduction and plasticizing processes and is accompanied by reduction reactions and desulfurization of metal particles. Mechanically degradable organics are used as solid-phase high-molecular compounds to promote metal grinding. A high-energy vibrating mill is employed to grind steel swarf, a single-crystal diffractometer for X-ray diffraction, and an infrared laser pyrometer to measure the temperature of the reactor walls during grinding. Polymethyl methacrylate is experimentally chosen as a high-molecular compound to generate active low-molecular components. The grinding of high-speed steel swarf together with the high-molecular organic compound leads to metal disintegration, which is a more energy-favored process that that occurring in the presence of low-molecular surface-active agents. The experiment has also demonstrated that there is no need to use labor-intensive annealing of the powder to eliminate mechanical work hardening since the vibration treatment of swarf in the presence of a degradable polymer leads to metal plasticizing. The time factor is used to describe the removal of adsorbed sulfur and that contained in steel from the metal and to describe the reduction of oxide films by the cracking products during mechanochemical treatment.

Plasma and collision processes of hypervelocity meteorite impact in the prehistory of life

Plasma and collision processes of hypervelocity meteorite impact in the prehistory of life

Influence of a high-intensity ultrasonic field on the removal of natural organic compounds from water

Organic compounds, which are considered water pollutants, have the ability to react with chlorine or other oxidants leading to the formation of products which pose a significant threat to human health. Humic substances play an important role in the formation of disinfection by-products. Therefore, the removal of organic compounds in the process of water treatment is of great importance. The application of ultrasound initiates a number of physicochemical processes in water which can be used in water treatment technologies, e.g. coagulation or adsorption. These methods, as well as the ion-exchange process, are applied in order to remove organic contaminants. With reference to the theoretical fundamentals of ultrasound, some sonochemical processes can result in a decrease in the content of color organic compounds in water. Increasing the intensity of ultrasonic field enhances the occurrence of sonochemical processes including the destruction of high-molecular organic compounds or the oxidation reactions with...

Sol-gel synthesis and investigation of proton-conducting hybrid organic-inorganic silicophosphate materials

Proton-conducting silicophosphate sol-gel systems modified by water-and alcohol-soluble low-molecular and high-molecular organic compounds (such as polyionenes, polyaminoguanidine, and organosilicon monomer) are synthesized by the sol-gel method. The physicochemical processes occurring in the course of the synthesis are investigated. It is revealed that the introduction of polyionenes into the sol-gel systems prevents the formation of silicon pyrophosphate crystals in the resulting silicophosphate nanocomposites (upon their heat treatment) and favors an increase in the protonic conductivity to 10−2 S/cm over a wide range of temperatures (0–120°C).

Evaluation of assimilable organic carbon in the Yodo River and the effect of coagulation on its control

Biodegradable organic compounds in Yodo River water, the coagulated water and those ozonated waters were characterized on the concentration of assimilable organic carbon (AOC), the apparent molecular size and the sensitivity to E260 (UV absorbance at the wavelength of 260 nm). High molecular (&amp;gt;5,000 Da) organic compounds which were insensitive to E260 were contained with relatively high concentration in Yodo River, whereas they were not detectable as AOC. The AOC concentration in Yodo River was reduced by coagulation because the phosphorus concentration sharply decreased. The AOC concentration rapidly increased with the reduction of E260 and slowly with the depolymerization of high molecular organic compounds during the ozonation. However, 40-50% of AOC increasing with the ozonation was reduced by the coagulation. Furthermore, batch incubations of native bacteria living in the Yodo River were conducted in order to examine the validity of the apparent AOC concentration as an indicator of the regrowth potential. The AOC concentration calculated as acetate carbon equivalent would not exactly represent the concentration of the available carbon for the assimilation. However, maximum cell numbers for the incubation period were generally proportional to apparent AOC concentrations even if phosphorus limitation. In conclusion, it is suggested that coagulation is an effective process in controlling the concentration of AOC and is a useful indicator to evaluate the regrowth potential of heterotrophic bacteria in Yodo River.

Amount and nature of soluble refractory organics produced by activated sludge microorganisms in sequencing batch and continuous flow reactors

Comparative experiments with a Sequencing Batch Reactor (SBR) and a continuous flow activated sludge system have been conducted in bench-scale to study factors affecting molecular composition and concentration of residual Soluble Microbial Products (SMP). It was experimentally confirmed that the amount of SMP in secondary effluents depends on applied process conditions, in particular on sludge age, hydraulic detention time distribution and concentration gradients within the bioreactor. The residual SMP consist of both low and high molecular organic compounds. The former prevail. The continuous flow system with a completely mixed aeration tank produced consistently higher concentrations of SMP than the SBR. The lowest SMP concentration was found at sludge ages between 5 and 15 days.

Amount and nature of soluble refractory organics produced by activated sludge micro-organisms in sequencing batch and continuous flow reactors

Comparative experiments with a Sequencing Batch Reactor (SBR) and a continuous flow activated sludge system have been conducted in bench-scale to study factors affecting molecular composition and concentration of residual Soluble Microbial Products (SMP). It was experimentally confirmed that the amount of SMP in secondary effluents depends on applied process conditions, in particular on sludge age, hydraulic detention time distribution and concentration gradients within the bioreactor. The residual SMP consist of both low and high molecular organic compounds. The former prevail. The continuous flow system with a completely mixed aeration tank produced consistently higher concentrations of SMP than the SBR. The lowest SMP concentration was found at sludge ages between 5 and 15 days.

Detection of glucosamine in the acid hydrolysis solution of humic substances.

Several humic substances isolated from water and soil have been characterized applying acid hydrolysis to release defined components bound in these high molecular organic compounds. The hydrolysis solution have been analyzed by HPLC after precolumn derivatization with o-phthalaldehyde and 9-fluorenylmethylchloroformate. Under these conditions the nitrogen containing carbohydrate glucosamine could be detected and separated besides seventeen amino acids. The results show that 8.0 to 40.1% of the total nitrogen content of the investigated samples contributes to amino acids and up to 7.9% to the carbohydrate glucosamine. It could be deduced that defined amino acid carbohydrate building blocks were bound in humic substances, because the glucosamine nitrogen content correlates with the calculated amino acid nitrogen. Furthermore the total amino acid nitrogen amount of natural organic matter can be estimated from the results of the determination of glucosamine.

Structure Analysis of High Molecular Organic Compounds with their Fragment Ions produced by Electron Impact

The mass spectra of 8, 8-dicyanoheptafulvene and its derivatives, which are considered to belong to a nonbenzenoid aromatic compound, were measured. The high degree of aromaticity of8, 8-dicyanotheptafulvene was made clear by masss pectrometry. Low mass regions of dicyanoheptofalvene showed the elimination of HCN from parent ion and rearrangement to phenvlpropiolonitrile ion. The mass spectra of methoxy-dicyanoheptafulvenes showed fragmentation quite different from that 8, 8-dieyanoheptafulvenes. The structure and fragmentation processes of dieyanoheptafulvenes were discussed.