Initial Alcohol Concentration Research Articles

Effect of concentration of aqueous alcohol solution and layer thickness on free convection due to local heating

This paper investigates the effect of point heating, ethyl alcohol concentration, and layer thickness on the convective behavior of the solution. Laser heating enhances heat and mass transfer at low energy costs. For the first time, the research determines boundaries of the transition to the chaotic behavior of the velocity field at a change in several parameters: the initial alcohol concentration and the initial thickness of the liquid layer. Simple estimated ratios are obtained to determine the critical value of the Bond number in a binary solution. The solution behavior is predominantly influenced by the solute Rayleigh and Marangoni numbers. A small alcohol concentration (about 10%) is shown to have a stabilizing effect on the velocity field. In the course of evolution, several flow patterns change sequentially, which is associated with changes in the gradient of surface tension, solution concentration and layer thickness with evaporation time.

Actual applications of infrared spectrophotometry in determining the quality of daily products

Fourier transform infrared spectroscopy (FTIR) is a fast and non-destructive analytical method. Combined with chemometrics, it is a powerful tool for the pharmaceutical, cosmetics and food industries. This method can be used for qualitative and quantitative analysis of medicines, foods and other daily products. At the same time, IR spectroscopy is becoming a suitable technique in the processes of drug preparation and for monitoring the productive processes in quality control laboratories. In this paper, IR spectroscopy is used to determine the concentration of alcohol in hand sanitizers, which is essential for slowing the spread of viruses. The effectiveness of hand sanitizer is entirely determined by the volatile ingredient, alcohol, which must remain at a concentration greater than 60\% (volume) to destroy bacterial and viral pathogens. The selected samples varied according to the initial concentration of ethyl alcohol, manufacturer, color, perfume and other ingredients, as well as the validity period.

Oxidation of Aqueous Dexamethasone Solution by Gas-Phase Pulsed Corona Discharge

The most widely used anti-inflammatory corticosteroid dexamethasone (DXM), frequently detected in waterbodies due to its massive consumption and incomplete removal in wastewater treatment processes, was experimentally studied for oxidation with gas-phase pulsed corona discharge (PCD) varied in pulse repetition frequency, pH, DXM initial concentration and additions of surfactant sodium dodecyl sulphate (SDS) and tert-butyl alcohol (TBA). The experimental study also included ozonation as compared to PCD in energy efficiency. The advantageous energy efficiency of PCD was observed in wide spans of pH and DXM initial concentrations surpassing ozonation by about 2.4 times. Identified transformation by- and end-products (fluoride and acetate), as well as the impact of radical scavengers, point to the prevalent radical oxidation of DXM. Somewhat increased toxicity observed on the course of PCD-treatment of high DXM concentrations presents a subject for further studies.

Analysis of fractional blood alcohol model with composite fractional derivative

Abstract The present article deals with certain new and interesting features of fractional blood alcohol model associated with powerful Hilfer fractional operator. The solution of the model depends on three parameters such as (i) the initial concentration of alcohol in stomach after ingestion (ii) the rate of alcohol absorption into the blood stream (ii) the rate at which the alcohol is metabolized by the liver. By employing Sumudu transform algorithm the analytic results of the concentration of alcohol in stomach and the concentration of alcohol in the blood are analyzed. The general solution of concentration of alcohol in stomach and the concentration of alcohol in the blood are demonstrated in the form of extended Mittag-Leffler function. The effect of fractional parameter on concentration of alcohol in stomach and the concentration of alcohol in the blood are shown in graphical form. The comparative study for both the concentrations shows the new features of composite fractional derivative in the discussed model. The discussed fractional blood alcohol model yields important and useful results to interpolate new information in the direction of medical environment.

Gasoline pre-blending processes for efficient ethanol recovery: effects of process parameters and process modifications for improved performance

With over 20 billion gallons of bio-ethanol produced annually, optimization of bio-ethanol production processes is a major priority for sustainability research. Recent research has made great strides toward improving the efficiency of bio-ethanol production through the development of gasoline pre-blending processes which use liquid–liquid phase separation to eliminate excess water with minimal energy input. This paper investigates the effects of process parameters on the performance and efficiency of this class of processes, offering a design basis for engineers developing new processes along with a broader understanding of their potential performance and economic value. Also explored are a range of process modifications capable of improving process performance. It has been found that blending ratio and initial alcohol concentration are the key parameters in determining ethanol recovery, with the number of liquid–liquid contact stages and the temperature also being significant. It has also been shown that temperature-swing decanting can significantly improve alcohol recovery, reducing ethanol losses by as much as 33% in a typical gasoline pre-blending setup.

Dynamics of Complete Evaporation of a Sessile Droplet of 1-Propanol–Water Solution at Different Ambient Humidities

Experimental data have been obtained on the complete diffusion evaporation of a sessile microdroplet of an aqueous 1-propanol solution on a hydrophobized polished quartz substrate in air at atmospheric pressure and room temperature. During the evaporation of the sessile droplet, time dependences have been determined for its key thermodynamic and geometric parameters, i.e., the contact angle, base surface area, and volume. It has been revealed that the character of time variations in the contact angle depends on the initial alcohol concentration in the droplet and air humidity. At a high alcohol concentration and a low air humidity, the droplet contact angle monotonically decreases throughout the evaporation process. The contact angle of a solution droplet with a prevailing content of water varies in several stages. In this case, the monotonic reduction in the contact angle is, at a certain moment, replaced by a stage of its growth. The comparison of the maximum contact angle of an evaporating droplet with the contact angle of a sessile droplet of pure water enables one to determine the amount of alcohol in a studied droplet by the end of this stage. The residual alcohol amount governs the subsequent evolution of the droplet up to its complete evaporation.

Marangoni Bursting: Evaporation-Induced Emulsification of Binary Mixtures on a Liquid Layer.

Adjusting the wetting properties of water through the addition of a miscible liquid is commonly used in a wide variety of industrial processes involving interfaces. We investigate experimentally the evolution of a drop of water and volatile alcohol deposited on a bath of oil: The drop spreads and spontaneously fragments into a myriad of minute droplets whose size strongly depends on the initial concentration of alcohol. Marangoni flows induced by the evaporation of alcohol play a key role in the overall phenomenon. The intricate coupling of hydrodynamics, wetting, and evaporation is well captured by analytical scaling laws. Our scenario is confirmed by experiments involving other combinations of liquids that also lead to this fascinating phenomenon.

Monodispersed Pd Nanoparticles Supported on Mg-Al Mixed Metal Oxides: A Green and Controllable Synthesis.

Aimed at the green synthesis of supported noble metal nanoparticles without any additional reducing agents or stabilizers at room temperature, a new strategy in which monodispersed Pd nanoparticles were successfully immobilized on Mg–Al mixed metal oxides derived from layered double hydroxides was developed, and the reduction mechanism was also proposed. It allowed the in situ immobilization of monodispersed Pd nanoparticles with a face-centered cubic structure, using only alcohols with α-hydrogen atom as the solvent and reducing agent. Control over the mean particle size and content of Pd nanoparticles was realized by adjusting the temperature, initial concentration, and type of alcohol. With the content of Pd varied from 6.4 to 42.3 mg/g, the mean particle size of Pd increased from 1.1 to 4.9 nm. The as-prepared catalyst showed high catalytic activity for oxidation of benzyl alcohol: when the Pd content was 6.4 mg/g, conversion of 60.3% and selectivity of 99.2% were obtained with a turnover frequency of 4807 h–1. Similarly, on the basis of the high stand electrode potentials, immobilized Ag (5.6 nm) and Au (4.7 nm) nanoparticles were also prepared through this methodology. Moreover, the choice of supports was extended to other powder supports that would react with the byproduced acid. Overall, this facile method opens up new opportunities for controllable synthesis of supported nanoparticle catalysts in a green way.

흑마늘의 첨가량과 초기 알코올 농도를 달리한 발효 식초의 품질특성

The quality characteristics of black garlic vinegar produced by acetic acid fermentation were analyzed over a 25 day period. Black garlic vinegar was produced using black garlic 3, 6, 9 and 12 folds with water, and initial alcohol concentrations of 6~12%. The pH values of the vinegar samples were in range of 3.85~4.46 after 25 days fermentation, and the sugar contents were highest after 9 days of fermentation (12.00~13.50 °Brix). The total polyphenol concents of vinegars were in the range of 20.65~52.04 mg/100 mL 25 days fermentation. Pyrogallol and vanillic acid were detected in the completely fermented vinegars, and their contents increased with black garlic content. Five organic acids (lactic acid, acetic acid, citric acid, succinic acid and propionic acid) were detected after 25 days of fermentation, with the total amount of organic acids being 5,327.34~6,307.64 mg/100 mL, and the total abetic acid contents beging the highest of the organic acids at 4208.90~5,570.29 mg/100 mL. After 25 days of fermentation, the total minerals contents were higher, and depending on the quantity of black garlic added. Of the minerals, the of potassium content was the highest (366.23~1,619.67 mg/L).

Effect of Nutrients and Growth Stimulators on Acetic Acid Fermentation using Natural Consortia

Acetic acid bacteria comprise a group of Gram negative, rod-shaped with aerobic metabolism using oxygen. From the natural inoculum, bacteria were isolated and characterized. Two main genera were determined as Acetobacter and Gluconobacter. Optimization of concentrations of alcohol, nitrogen source, phosphate source and magnesium sulphate was carried out by applying central composite design (CCD) of RSM for preparation of apple cider vinegar. Apple wine and cider vinegar was prepared by using optimized conditions from response surface methodology (RSM) experiment. Acetic acid fermentations were carried out with different cultures and growth regulators. The treatment having maximum titratable acidity (5.07%) was achieved in run number 2 having 5% initial alcohol concentration, 0.5% K2HPO4 and 0.25% ammonium sulphate with natural consortia. It was found that the maximum acidity of 4.56% was achieved in run number 23 having 5% alcohol concentration, 1.25% yeast extract, 0.25% NH2HPO4 and 0.55% MgSO4 with natural consortia. It is concluded that to have optimum acetic acid production for cider vinegar production, the optimized concentration of nutrients and growth regulators was suitable, using natural consortia in the form of pellicle.

2단계 발효로 제조된 고산도 사과식초의 품질지표성분 설정

In this study, high-acidity cider vinegar (HACV) was produced by alcoholic and acetic acid fermentation of apple concentrate without any nutrients and then the optimum alcohol concentration was determined through a qualitative study. HACV was fermented with different initial alcohol concentrations (6-9%) during the process of acetic acid fermentation. The highest content of reducing sugar, organic acids, and free amino acids was observed at 6% of initial alcohol concentration. Approximately 20 types of volatile compounds were identified by solid-phase microextraction (SPME) and GC-MS. The total volatile content was the highest at 6% of initial alcohol concentration, and the acid content was the lowest at 9% of the initial alcohol concentration. The HACV produced by a two-stage fermentation process was qualitatively better than commercial HACV presenting the highest value at 6% of initial alcohol concentration. Malic acid, aspartic acid, and hexyl acetate were selected as quality index components of HACV production by two-stage fermentation on the basis of correlation between their physicochemical properties and the sensory attributes of HACV.

Physicochemical properties and volatile components of wine vinegars with high acidity based on fermentation stage and initial alcohol concentration

High acidity vinegar using grape concentrate was manufactured by fed-batch fermentation without additional chemical nutrients. Physicochemical properties and volatile components were investigated at different wine vinegar fermentation stages (stages 1–4) and at different initial alcohol concentrations (IAC, 6–9%). Acetic acid production showed a high yield and a rapid increase with an IAC=6%. The contents of reducing sugar, free amino acids, total phenolics, and overall volatiles increased during stage 4 (high acidity vinegar) most likely due to addition of a feeding solution. High acidity vinegar produced using a fed-batch culture at an IAC of 6% is a source of functional constituents with improved physicochemical and volatile properties, compared to moderate acidity vinegar.

반응표면분석법을 이용한 아로니아 식초 제조를 위한 발효조건 최적화

This study was conducted to determine the optimal conditions of acetic acid fermentation of aronia using the response surface methodology (RSM). Alcohol content of aronia wine was 13.1% after alcohol fermentation of aronia fruits. The optimal conditions of acetic acid fermentation were determined by five levels of initial aronia alcohol content, initial acetic acid content, and acetic acid bacteria, using the central composite design. The acetic acid yields, residual alcohol contents, pH, and color values (L, a, b) of acetic acid fermentation products were very significantly different (p≤0.01), and were 26.34~57.82 g/L, 0.80~1.53%, 3.19~3.43, 47.58~71.00, 31.77~51.15, and 18.45~48.57, respectively. For the results, the optimal conditions of acetic acid fermentation of aronia were 7.78% of the initial alcohol concentration, 1.58% of the initial acetic acid, and 19.39% of the acetic acid bacteria.

고산도 배식초 제조 시 발효조건에 따른 품질특성

배 농축액의 유가식 배양을 통해 영양원 없이 산도 12% 이상의 고산도 식초를 제조하면서 발효단계(Stage 1-4) 및 초기 알코올농도(6-9%)에 따른 품질특성 변화를 확인하였다. 환원당, 유리아미노산, 총 페놀 함량, 총 플라보노이드 함량 및 라디칼 소거능은 1차 초산발효한 일반산도 식초에 비해 2차 초산발효한 고산도 식초에서 증가하였고, 이는 유가식으로 첨가된 feeding 알코올의 영향으로 사료되었다. SPME/GC-MS 분석을 통한 20여종의 휘발성분은 식초의 산도에 따라 함량의 차이를 나타내었고, 초기 알코올농도의 증가에 따라 자극적인 향의 acid류 함량이 다소 증가하였다. 이상의 결과, 초기알코올 농도 6-7% 조건에서 유가식 배양으로 제조된 고산도 배식초는 일반산도 식초에 비해 우수한 품질을 나타내었고, 이에 관능특성 및 대규모 생산에 대한 연구가 필요한 것으로 사료되었다. High-acidity vinegar was manufactured using pear concentrate by fed-batch fermentation without additional nutrients, and the physicochemical properties and volatile components were investigated at different fermentation stages (Stages 1-4) and at various initial alcohol concentrations (IAC; 6-9%). The levels of reducing sugar, free amino acids, total phenolic content, total flavonoid content, and radical scavenging ability increased slightly during Stage 4 (high-acidity vinegar), which was affected by alcohol feeding. The contents of approximately 20 types of volatile compounds differed between the moderate- and high-acidity vinegar samples, as determined by solid-phase microextraction/gas chromatography-mass spectroscopy. The level of acetic acid in high-acidity vinegar increased according to the initial alcoholic content applied. The high-acidity vinegar produced by fed-batch culture at an IAC of 6-7% showed improved physicochemical and volatile properties as compared to the moderate-acidity vinegar.

Particle settling characteristics of alcohol precipitation mixture of Paeoniae Radix rubra extract and models establishment of settling velocity

To understand the particle settling characteristics of alcohol precipitation mixture of Paeoniae Radix rubra extract and establish models of the sedimentation rate. Focusing on the particle settling characteristics such as particle settling curve, particle settling velocity (PSV), particle volume index (PVI), the particle settling process of alcohol precipitation was investigated. The effect of three key process factors on the settling process was discussed and mathematical models for describing the particle settling velocity were developed. Controlling of higher final alcohol concentration, higher density of Paeoniae Radix rubra extract, or lower initial alcohol concentration, was conducive to settlement of alcohol precipitation particles. In the constant speed phase, an empirical calculation formula of v(0) was established, with both the variables PSV and PVI (v(0)=-0.236PSV+0.022PVI+7.521). Another developed model was applied to predict the settling velocity in decelerated phase and the simulation was very good [v=k(1-n(1)X)(4)exp(-n(2)X)/X]. The results of this work will contribute to a better control and optimization of alcohol precipitation process, and help to implementation of accuracy control in the manufacture of botanical medicines.

Reaction Kinetics of Catalytic Esterification of Nonanoic Acid with Ethanol over Amberlyst 15

AbstractThe kinetic behaviour of heterogeneous esterification of nonanoic acid with ethanol over an acidic cation exchange resin, Amberlyst 15, was investigated in a batch reactor and effect of various parameters such as catalyst loading, molar ratio and reaction temperature on degree of fractional conversion has been studied. Internal and external diffusions were found to be negligible in this study. Nonideality of the liquid phase was taken into account by using activities instead of concentrations. The activity coefficients were estimated using UNIFAC group contribution method. Eley–Rideal (ER) kinetic model was used to interpret the obtained kinetic data. The temperature-dependent initial reaction rate constants and the adsorption coefficients for ethanol and water were determined from the observed experimental data obtained at different initial concentration of acid, alcohol and water. Activation energy and pre-exponential factor of the reaction were found to be 53.7 kJ mol−1and 1.51×105l2g−1mol−1h−1respectively.

Photocatalytic performance of Li1−xAgxVMoO6 (0 ⩽ x ⩽ 1) compounds

In this work we report the influence of silver content on the structure and photocatalytic performance of Li1−xAgxVMoO6 compounds for the oxidation of benzyl alcohol under UV irradiation (λ=254nm). Photocatalysts were synthesized by solid state method and their structural and morphologic characterization was carried out by powder X-ray Diffraction, Raman Spectroscopy, SEM, TEM, UV–Vis diffuse reflectance spectroscopy and XPS. The effect of variables including silver content, temperature, catalyst concentration and initial concentration of benzyl alcohol on photocatalytic performance were studied. Experimentation was also carried out with TiO2 (Degussa P25) as reference. It was found that all tested Li1−xAgxVMoO6 (0⩽x⩽1) compounds exhibit higher photocatalytic efficiency than TiO2. However, among mixed oxides, silver was found to diminish their catalytic performance and selectivity towards benzaldehyde. The latter was affected in much less extent than activity (94%, 90% and 87% for LiVMoO6, Li0.8Ag0.2VMoO6 and AgVMoO6, respectively). Kinetic modelling was carried out based on Langmuir–Hinshelwood type expressions. Apparent activation energies were found to be 42kJmol−1 and 60.17kJmol−1 for LiVMoO6 and TiO2, respectively.

Blood Alcohol Content

Given a set of differential equations describing blood alcohol content as a function time, we integrated the equations to obtain a general solution. The general solution equation depends on three free parameters: the initial concentration of alcohol in the stomach after ingestion, the rate of alcohol absorption into the blood stream and the rate at which the alcohol is metabolized by the liver. We fitted our solution to experimental data to determine the unknown parameters for a particular subject.

Intensification of gas-phase photoxidative dehydrogenation of ethanol to acetaldehyde by using phosphors as light carriers

In this work a significant improvement of VO(x)/TiO(2) photocatalytic activity in the selective partial oxidation of ethanol to acetaldehyde was achieved by the simultaneous irradiation with light emitting phosphorescent particles and UVA-LEDs as external light source. Photocatalytic tests were carried out in a gas-solid photocatalytic fluidized bed reactor at high illumination efficiency, in which the bed is constituted by VO(x)/TiO(2) photocatalyst at nominal V(2)O(5) content of 5 wt% and suitable selected phosphors, diluted with glass spheres. In this way, phosphors were fluidized together with the catalyst, excited by external UVA-LEDs, emitting their stored energy in close proximity to the catalyst. In the absence of phosphors the ethanol consumption rate initially grows linearly with initial alcohol concentration, then bends towards an asymptotic value for initial ethanol concentration higher than 0.5 vol%. By contrast, when phosphors are present, the ethanol consumption rate increased linearly in the overall range. In all cases acetaldehyde was the main product detected in gas phase with a selectivity of about 97%, ethylene and carbon dioxide the by-products. The results evidenced that the presence of phosphors allowed improved photon transfer, increasing the apparent quantum yield from 2 to 30% together with a high photoreactivity.

Highly Selective Oxidation of Benzyl Alcohol Using Engineered Gluconobacter Oxydans in Biphasic System

The Gluconobacter oxydans M5 with disruption of the pyrroloquinoline quinine-dependent membrane-bound aldehyde dehydrogenase (ALDH) was used for the oxidation of benzyl alcohol. The selectivity toward benzaldehyde showed an obvious increase for the engineered strain, which reached the 67.3%, while the wild strain had only 2.8%. Meantime, the aqueous/isooctane (1:1) biphasic system was used for the further improvement of selectivity. By these methods, nearly 100% selectivity and conversion rate could be obtained within 1 h at the optimum initial benzyl alcohol concentration of 5.0 g/l.