Organic Alkali Research Articles

Mathematical modeling of transesterification process kinetics of triglycerides catalyzed by TMAH

Biodiesel is a renewable fuel mainly produced by methylation of triglycerides of vegetable oils or animal fats. The production processes nowadays are particularly based on the utilization of inorganic alkali catalysts. However, it has been proved that an organic alkali – tetramethylammonium hydroxide (TMAH) – can also be used as a very efficient transesterification catalyst. The work presented herein is focused on mathematical modeling of the kinetics of TMAH-catalyzed transesterification of triglycerides at different reaction conditions, specifically at varying reaction temperature with the aim to understand the reaction mechanism and identify the key variables for optimization of the production process. The main kinetic parameters were calculated based on the mathematical- statistical processing of experimental kinetic data. The reaction rate constants for individual consecutive and reversible reactions and the corresponding activation energies were calculated.

Chemical Interactions and Mechanisms of Different pH Regulators on Copper and Cobalt Removal Rate of Copper Film CMP for GLSI

As the feature size of integrated circuits (ICs) shrinks down to 14nm and below, Cobalt (Co) is identified as a suitable barrier layer material. Copper (Cu) has been widely used as the most basic interconnection metallic material for Giant-large scale integrated circuits (GLSI). A higher removal rate (RR) selectivity between Cu and Co is desired to obtain in copper film chemical mechanical polishing (CMP) because the traditional three-step polishing is replaced by two-step polishing of copper and barrier under lower technology nodes. The purpose of copper film polishing is to achieve effective removal of Cu and ultimately stop on the layer of Co. The pH value of slurry is a critical factor affecting the material removal rate and the stability of the slurry. The influence of different kinds of pH regulators and different pH values on the removal rates and the stability of slurries were investigated in this paper. Three pH regulators were chosen in the experiments, containing macromolecular chelating agent FA/OII as organic alkali, KOH as inorganic alkali and KOH mixed with a small amount of tetraethyl ammonium hydroxide (TEAH, C8H21NO) as mixed alkali. According to the investigation of removal rate results and stability experiments results, 10.5 was identified as a suitable pH value and a relatively higher removal rate selectivity was obtained. Meanwhile, using the mixed alkali to adjust slurry pH value can effectively increase the selectivity of Cu and Co and the stability of the copper slurry. The adsorption of TEAH on Cu and Co surface was considered as the critical reason relating to the slight removal rate decline, which was verified by XPS measurements.

Effect of organic amine alkali and inorganic alkali on benzotriazole removal during post Cu-CMP cleaning * * Project supported by the Major National Science and Technology Special Projects (No. 2016ZX02301003-004-007), the Natural Science Foundation, China (No. 61704046), and the Hebei Natural Science Foundation Project (No. F2018202174).

Benzotriazole (BTA), an anticorrosion agent of slurry, is the main organic pollutant remaining after CMP of multilayer copper wiring, and also the main removal object of post CMP cleaning. The adsorption of BTA onto the copper could form a dense Cu-BTA film, which makes the copper surface strongly passivated. According to this characteristic, quantitative analysis of BTA residue after cleaning is carried out by contact angle measurement and electrochemical measurement in this paper. A scanning electron microscope (SEM) with EDX was used to observe and analyze the BTA shape and elements. The efficiencies of organic alkali and inorganic alkali on the removal of BTA were studied. The corresponding reaction mechanism was also analyzed. The results show that the adsorption structure of Cu(I)-BTA cannot be destroyed in an alkaline environment with a pH less than 10; the effect of BTA removal by inorganic alkali is worse than that of the organic amine alkali with the coordination structure under the same pH environment; the FA/O II chelating agent with the fraction of 200 ppm can effectively remove BTA residue on the surface of copper wafer.

An Experimental Study of Emulsion Phase Behavior and Viscosity for Athabasca Bitumen/Diethylamine/Brine Mixtures

Summary Water is the most dominant component in steam-based oil-recovery methods, such as steam-assisted gravity drainage (SAGD). The central question that motivated this research is whether in-situ bitumen transport in SAGD can be substantially enhanced by generating oil-in-water emulsion, in which the water-continuous phase acts as an effective bitumen carrier. As part of the initial stage of the research project, the main objective of this paper is to present the ability of organic alkali to form oil-in-water emulsions that are substantially less viscous than the original bitumen. Diethylamine (DEA) was used as the organic alkali in this research. Experimental studies were conducted for emulsion phase behavior and viscosity for mixtures of Athabasca bitumen, DEA, and sodium chloride (NaCl) brine. Experimental variables included brine salinity, alkali concentration, water/oil ratio (WOR), temperature, and sample-aging time. The phase-behavior study indicated that conditions conducive to oil-in-water emulsions are low alkali concentrations at salinities less than 1,000 ppm. For example, a single phase of oil-in-water emulsion was observed for 0.5, 1.0, 2.0, and 5.0 wt% DEA with WOR of 7:3 with no NaCl. The emulsion for 0.5 wt% DEA, 1,000 ppm NaCl, and WOR of 7:3 was a single-phase oil-in-water emulsion at temperatures up to 403 K at 35 bar. At lower temperatures, 323 and 298 K, flocculation of emulsions in these samples resulted in the separation between the bitumen-rich and water-rich oil-in-water emulsions. However, essentially all bitumen content was measured from the bitumen-rich oil-in-water emulsion. The oil contents in these emulsions were more than 70 vol% at 298 K and 57 vol% at 323 K. Viscosities of these oil-in-water emulsions ranged between 85 and 115 cp at 1.0 seconds–1 and between 31 and 34 cp at 10.0 seconds–1, at 323 K. At 298 K, they ranged between 105 and 250 cp at 1.0 seconds–1 and between 48 and 74 cp at 10.0 seconds–1. Results in this research show that, compared with the original bitumen, bitumen-rich oil-in-water emulsions were less viscous by three to four orders of magnitude at 298 K, and less viscous by two orders of magnitude at 323 K.

A Novel Recycling Technology of Bamboo Using NaOH

The bamboo industry in Japan is declined, and disordered bamboo forests are increasing. Although maintenance of bamboo forest is needed, a large amount of bamboo wastes after logging is generated and left untreated. Therefore, new utilization of bamboo wastes after logging are desired. In this research, we aimed to develop a new recycling technology for bamboo using alkali hydroxide. By pyrolyzing bamboo using hydroxide under an inert atmosphere, thermal decomposition of organic contents and alkali fusion of silica component inside the bamboo were carried out simultaneously to recover combustible gas, charcoal and silica component. The thermal decomposition behavior of bamboo, the properties of the obtained charcoal and extraction of silica in the presence of alkali hydroxide were investigated, and the optimum condition of bamboo recycling treatment was examined. As a result, it was found that when 1 g of bamboo was pyrolyzed at higher than 500 °C with 3 g NaOH ,the almost silica was extracted, a large amount of gas generated, and a carbonized material with specific surface area of about more than 1100 m2 /g was obtained.

A chemical treatment method for obtaining clean and intact pollen shells of different species.

Pollen grains and plant spores have emerged as a novel biomaterial for a broad range of applications including oral drug and vaccine delivery, catalyst support, and removal of heavy metals. However, before pollens can be used, their intrinsic biomolecules, which occupy a large part of the pollen inner cavity must be removed not only to create empty space but because they have potential to cause allergies when used in vivo. These intrinsic materials in the pollen core can be extracted through a chemical treatment to generate clean pollen shells. The commonly used method involves a series of sequential treatments with organic solvents, alkalis, and acids to remove the native pollen biomolecules. This method, though successful for treating lycopodium (Lycopodium clavatum) spores, fails for other species of pollens such as common ragweed (Ambrosia elatior) and thus prevents widespread investigation of different pollens. Herein, we report a new chemical treatment for obtaining clean pollen shells from multiple plant species. This new method involves sequential treatment with acetone, phosphoric acid, and potassium hydroxide. Scanning electron micrographs and protein quantification have shown that the new method can successfully produce clean, intact, and hollow shells from many pollen species including ragweed, sunflower, black alder, and lamb's quarters. These results demonstrate the broad applicability of this method to clean pollens of different species, and paves the way to start investigating them for various applications.

Characterization of alkali-surfactant-polymer slugs using synthesized gemini surfactant for potential application in enhanced oil recovery

The present study deals with the formulation and characterization of alkali-surfactant-polymer slugs using gemini surfactant (GS) for effective application in enhanced oil recovery (EOR) processes. The hydrolytic stabilities of the synthesized cationic GSs were measured in both acidic and basic media. Surface tensiometry was employed to determine the CMC values of surfactant at different temperatures. An organic alkali, monoethanolamine (MEA) showed the most favourable interfacial properties at the oil-aqueous interfaces among the various experimented alkalis. Though the addition of PHPA polymer to GS/MEA solutions increase the IFT value, the viscosities of the slugs improve drastically, which is desirable to improve the sweep efficiency. The solutions also showed low turbidity values and high thermal stability over a significant time period. The oil-surfactant-aqueous systems showed favourable emulsification properties, showing the ability to effectively displace trapped oil. Viscosity increases with PHPA concentration due to mixed micelle associations among the surfactant, alkali and polymer molecules. At low shear rates, the GS/MEA/PHPA solutions exhibited shear thinning properties. Oscillatory studies show the presence of both viscous and elastic properties, which have been well described using the Maxwell mechanical model. Formulation consisting of 0.02% 14-6-14 GS, 0.80% MEA and 0.20% PHPA showed the most favourable tertiary recovery after conventional secondary water-flooding.

Preparation of N,N,N-trimethyl-1-adamantylammonium hydroxide with high purity via bipolar membrane electrodialysis

N,N,N-trimethyl-1-adamantylammonium hydroxide (TMAdaOH) is an organic alkali compound with important applications in the catalyst industry. In this study, bipolar membrane electrodialysis (BMED) was employed for the preparation of TMAdaOH from its halide with a BP-C1-A1-C2-BP four-compartment configuration. The effects of operating conditions (feed concentration and current density) on the performance of BMED were investigated. The results indicated that at optimum operational conditions (feed concentration of 0.3 mol/L and current density of 8 mA·cm−2), a conversion rate of 76.8% can be obtained, with an energy consumption of only 3.22 kWh/kg. The purity of product is extremely high and Cl− content in the TMAdaOH solution can reach as low as 68 ppm. Due to the importance of cation-exchange membrane to the process, different types of cation membrane were compared. In addition, repeated experiments were conducted to prove the stability of BMED process.

Emulsification of Athabasca bitumen by organic alkali: Emulsion phase behavior and viscosity for bitumen/brine/triethylenetetramine

Recovery of bitumen commonly uses steam assisted-gravity drainage, in which water throughput is intrinsically high. A large amount of condensed water near thermal fronts tends to substantially decrease the effective permeability to bitumen in the conventional gravity drainage process. This research investigates a potential way to use the condensed-water phase as an effective carrier for bitumen by making oil-in-water (o/w) emulsion. The expected mechanism depends on emulsification of bitumen into the water phase by natural surfactants that are generated through reactions of acidic oil components with organic alkali.The main objective of this paper is to study the ability of an organic alkali to create o/w emulsions that are much more mobile than the original bitumen. Triethylenetetramine (TETA) was selected as organic alkali for this paper with no other additives. The main contribution of this paper is a new set of experimental data (phase behavior and viscosities) for emulsions for mixtures of Athabasca bitumen, TETA, and NaCl brine at a wide range of alkali concentrations, salinities, and water-to-oil ratios (WORs) at temperatures up to 373 K.Results show that the o/w emulsions created by TETA can be an effective bitumen carrier with a low viscosity and high bitumen content in the emulsion. It is possible to create o/w emulsions by adding a small amount of TETA to Athabasca bitumen and NaCl brine. Single-phase o/w emulsions, which are desirable as a bitumen carrier, were observed for TETA concentrations below 5.0 wt% at salinities 0 ppm and 1000 ppm at 373 K. The bitumen content in o/w emulsion was the highest for 2.0 wt% TETA samples, and it increased with increasing temperature. In comparison to the original bitumen, o/w emulsions were 4–5 orders of magnitude less viscous at 298 K, 2 to 3 orders of magnitude less viscous at 323 K, and 1 to 2 orders of magnitude less viscous at 353 K.

Regulate the coupling reaction of 4-nitrothiophenol to 4,4′-dimercaptoazobenzene by organic alkali

Regulate the coupling reaction of 4-nitrothiophenol to 4,4′-dimercaptoazobenzene by organic alkali

Mechanistic studies of enhanced oil recovery by imidazolium-based ionic liquids as novel surfactants

Ionic liquids are recently considered as an alternation to surfactants for their application in enhanced oil recovery (EOR) because of their promising surface-active properties. In the present study, the ability of a series of synthesized ionic liquids (C8mimBF4, C10mimBF4 and C12mimBF4) to reduce interfacial tension (IFT) and change the wettability of oil-wet rock have been investigated. Results demonstrated that all three synthesized ionic liquids enhanced interfacial properties and rock-wetting characteristics. The ionic liquids were able to significantly reduce IFT and remained stable at high temperature and saline conditions. Addition of organic alkali also showed a synergistic effect on IFT reduction between crude oil and ionic liquid solution. FTIR and zeta potential measurements were conducted to establish the mechanism of wettability alteration of oil-wet rock. Emulsification tests confirmed the capability of the ionic liquids to emulsify the trapped oil, which is an important mechanism of chemical EOR. The loss of ionic liquids by adsorption on rock surface was studied, and the adsorption data were analyzed by Langmuir and Freundlich models. Microemulsion study showed Winsor type III behavior with ultra-low IFT, which is beneficial for EOR application. Sand pack flooding experiments were conducted to study the EOR efficiency using the synthesized ionic liquids and around 32.28% additional recovery was observed after the conventional water flooding with injection of ionic liquid, polymer and alkali slugs.

Direct determination of poly(3-hydroxybutyrate) accumulated in bacteria by thermally assisted hydrolysis and methylation-gas chromatography in the presence of organic alkali

Abstract There is considerable interest in the development of simple methods for quantifying production of the biodegradable polyester poly(3-hydroxybutyrate) [P(3HB)] by bacteria. Cells of Cupriavidus necator were grown on agar medium containing different concentrations of glucose (10–25 g/L) as a sole carbon source. Trace amounts (100±5 μg) of dried C. necator cells were directly subjected to thermally assisted hydrolysis and methylation-gas chromatography (THM-GC) in the presence of tetramethylammonium hydroxide (TMAH). On the resulting chromatograms, a series of characteristic peaks, attributed to the THM products from poly(3-hydroxybutylate) accumulated in the bacterial cells, were clearly observed without any interfering component. Based on the peak intensities, the contents of P(3HB) in C. necator were determined precisely and rapidly without using any cumbersome sample pretreatment. Furthermore, the values of the P(3HB) contents coincided overall with those obtained by the conventional method involving solvent extraction followed by gravimetric determination.

Rapid Analysis of Fatty Acid Composition in Polysorbate 80 by Gas Chromatography with On-line Pyrolytic Methylation Technique

A novel method of on-line pyrolytic methylation–gas chromatography was developed for the rapid analysis of fatty acid composition in Polysorbate 80 without any tedious pre-treatment steps. Fatty acids in Polysorbate 80 were converted into their corresponding fatty acid methyl esters in the presence of trimethylsulfonium hydroxide with a vertical microfurnace pyrolyzer at 300 °C. The premixing procedure of sample and organic alkali reagent was necessary before the on-line pyrolytic methylation to improve the repeatability. The relative standard deviations for peak areas of fatty acids in Polysorbate 80 were over the range of 0.3–9.1% (n = 5). Six Polysorbate 80 samples, consisting of three samples of pharmaceutical grade and three samples of non-pharmaceutical grade, were analyzed to evaluate the feasibility of the proposed method. The relative percentages (%) of fatty acids for samples of pharmaceutical grade meet the Chinese Pharmacopoeia requirements with the amount of oleic acid varying from 78.4 to 89.3%. On the other hand, the relative percentages (%) for palmitic acid and stearic acid in samples of non-pharmaceutical grade were out of the specification limits, with the amount of oleic acid varying from 62.0 to 63.5%. The quantitative results determined by on-line pyrolytic methylation were in agreement with those obtained by off-line methylation. The result proved that gas chromatography with on-line pyrolytic methylation technique is of great value for rapid screening analysis of Polysorbate 80 samples in bulks.

Responses of soil physical and chemical properties to karst rocky desertification evolution in typical karst valley area

In order to reveal the differences of soil physical and chemical properties and their response mechanism to the evolution of KRD. The characteristics of soil physical and chemical properties of different grades of KRD were studied by field sampling method to research different types of KRD in the typical karst valley of southern China. Instead of using space of time, to explore the response and the mechanisms of the soil physical and chemical properties at the different evolution process. The results showed that: (1) There were significant differences in organic matter, pH, total nitrogen, total phosphorus, total potassium, sediment concentration, clay content and AWHC in different levels of KRD environment. However, these indicators are not with increasing desertification degree has been degraded, but improved after a first degradation trends; (2) The correlation analysis showed that soil organic matter, acid, alkali, total nitrogen, total phosphorus, total potassium and clay contents were significantly correlated with other physical and chemical factors. They are the key factors of soil physical and chemical properties, play a key role in improving soil physical and chemical properties and promoting nutrient cycling; (3) The principal component analysis showed that the cumulative contribution rate of organic matter, pH, total nitrogen, total phosphorus, total potassium and sediment concentration was 80.26%, which was the key index to evaluate rocky desertification degree based on soil physical and chemical properties. The results have important theoretical and practical significance for the protection and restoration of rocky desertification ecosystem in southwest China.

Synthesis and Properties of Ni-doped Goethite and Ni-doped Hematite Nanorods

Ni-doped goethite (α-FeOOH) nanorods were synthesized from mixed Fe(III)-Ni(II) nitrate solutions with various Ni/(Ni+Fe) ratios (0, 5, 10, 20, 33 and 50 mol % Ni) by hydrothermal precipitation in a highly alkaline medium using the strong organic alkali, tetramethyl¬ammonium hydroxide (TMAH). Ni-doped hematite (α-Fe2O3) nanorods were obtained by calcination of Ni- doped goethite nanorods at 400 °C. The Ni2+- for-Fe3+ substitution in goethite and hematite was confirmed by determination of the unit cell expansion (due to the difference in the ionic radii of Fe3+ and Ni2+) using XRPD and determination of the reduction of a hyperfine magnetic field (due to the difference in magnetic moments of Fe3+ and Ni2+) using Mossbauer spectroscopy. Single- phase goethite nanorods were found in samples containing 0 or 5 mol % Ni. A higher Ni content in the precipitation system (10 mol % or more) resulted in a higher Ni2+-for-Fe3+ substitution in goethite, and larger Ni-doped goethite nanorods, though with the presence of low crystalline Ni-containing ferrihydrite and Ni ferrite (NiFe2O4) as additional phases. Significant changes in FT-IR and UV-Vis-NIR spectra of prepared samples were observed with increasing Ni content. Electrochemical measurements of samples showed a strong increase in oxygen evolution reaction (OER) electrocatalytic activity with increasing Ni content.

Characterizations of surfactant synthesized from palm oil and its application in enhanced oil recovery

The present work deals with synthesis of an anionic biodegradable surfactant for application in chemical enhanced oil recovery (EOR) process. Alpha sulfonated ethyl ester (α-SEE) was synthesized from palm oil via trans-esterification process. The surfactant was characterized by FTIR, GC, TGA, FE-SEM and EDX analyses. Critical micelle concentration (CMC) was determined by surface tension measurement at air–aqueous interface. The efficiency of α-SEE was studied by calculating the interfacial tension (IFT) between crude oil and surfactant solution, and by investigating the ability of the surfactant to alter the wettability nature of carbonate and quartz surfaces. Salt effect was studied at CMC of surfactant to obtain an ultra-low IFT value of the order of 10−3 mN/m at optimal salinity. Addition of organic alkali also showed synergistic effect on IFT between crude oil and surfactant solution. The surfactant favorably altered the wettability of oil-wet carbonate and quartz surfaces to water-wet, which is desirable for oil recovery. The surfactant showed potential application in EOR owing to its enhanced interfacial properties and rock-wetting characteristics. Flooding experiments were conducted with surfactant slugs at different α-SEE concentrations to achieve about 25%–27% additional oil recoveries after conventional flooding.

Dual Alkali Solvent System for CO2 Capture from Flue Gas.

A novel two-aqueous-phase CO2 capture system, namely the dual alkali solvent (DAS) system, has been developed. Unlike traditional solvent-based CO2 capture systems in which the same solvent is used for both CO2 absorption and stripping, the solvent of the DAS system consists of two aqueous phases. The upper phase, which contains an organic alkali 1-(2-hydroxyethyl) piperazine (HEP), is used for CO2 absorption. The lower phase, which consists of a mixture of K2CO3/KHCO3 aqueous solution and KHCO3 precipitate, is used for CO2 stripping. Only a certain kind of amine (such as HEP) is able to ensure the phase separation, satisfactory absorption efficiency, effective CO2 transfer from the upper phase to the lower phase, and regeneration of the upper phase. In the meantime, due to the presence of K2CO3/KHCO3 in the lower phase, HEP in the upper phase is capable of being regenerated from its sulfite/sulfate heat stable salt, which enables the simultaneous absorption of CO2 and SO2/SO3 from the flue gas. Preliminary experiments and simulations indicate that the implementation of the DAS system can lead to 24.0% stripping energy savings compared to the Econamine process, without significantly lowering the CO2 absorption efficiency (∼90%).

The Application of Ionic Liquid Composite Materials in Denitrification from Flue Gas

In this paper, ionic liquid BMIMPF6 was synthesized and characterized by IR and 1H NMR, and the properties, such as melting point, density, viscosity conductivity and the solubility with common solvents were detected. The NO2 solubility in composite materials composed of ionic liquid and organic base was also discussed, the absorption process was optimized and the absorption mechanism was speculated. The results showed that the purity of ionic liquid is 99% by 1H NMR. The properties of ionic liquid are basically identical with literature reported data. Under the optimum experimental conditions, the composite material composed of the ionic liquid and the organic alkali showed a high NO2 absorption amount of 0.311gNO2/g ionic liquid composite material, and the absorption process is a physical and chemical process. The ionic liquid composite material can be recycled for 4 times, and the absorption effect is basically unchanged.

Effect of Steam Explosion Pretreatment Catalysed by Organic Acid and Alkali on Chemical and Structural Properties and Enzymatic Hydrolysis of Sugarcane Bagasse

This study researched the steam explosion effect catalysed by citric acid and sodium hydroxide on the chemical and structural properties of sugarcane bagasse and on the enzymatic hydrolysis process. Chemical and structural characterisation of raw and pretreated biomass was performed by reference methodologies for lignocellulosic materials, FTIR, XRD, TGA and SEM. Enzymatic hydrolysis was performed with a final volume of 20 mL consisting 3% sugarcane bagasse (dry weight), sodium citrate buffer 50 mM (pH = 5.0) and 1 g enzyme/100 g cellulose of Cellic® Cetec 3 enzyme complex. The total reducing sugars were determined by a 3,5-dinitrosalicilic acid method. In explosion pretreatment catalysed by citric acid, a biomass was obtained with a lesser amount of hemicelluloses (16.16%), a higher initial degradation temperature and formation of cracks in fibre cell wall. Pretreated bagasse by NaOH steam explosion showed complete destructuring of fibre, lignin removal of 65% and hemicellulosic fraction preservation. Sugarcane bagasse obtained after NaOH steam explosion showed the highest production of reducing sugars (9.07 g L−1), which can be attributed to greater exposure of carbohydrate fraction promoted by lignin removal, since these parameters showed a strong negative correlation (r = −0.99, p < 0.05).

Experimental Evaluation of a Surfactant/Compound Organic Alkalis Flooding System for Enhanced Oil Recovery

Monoisopropanolamine (MIA) and monoethanolamine (MEA), which are two kinds of organic alkalis, present favorable potential for enhanced oil recovery. When MIA and MEA are respectively applied, the minimum oil/water interfacial tension (IFT) can be reduced to about 1 mN/m, the crude oil can be emulsified, and the originally oil–wet sand surface can be altered to weak water-wet status. To display the synergistic effect of surfactant and organic alkalis, a surfactant/compound organic alkalis (MIE/MEA) flooding system (SMM), which consists of 0.10 wt % SDBS, 0.15 wt % MIA, and 0.10 wt % MEA, is screened. This system can reduce the minimum oil/water IFT to an ultralow value which contributes to the emulsion stability. Results of sandpack flooding tests indicate that although the incremental oil recovery can be continuously enhanced with the increase of the SMM slug size, there is an optimal injection size (0.8 PV in this study) when the expense is taken into consideration. As for the effect of the injection ty...