Vigreux Column Research Articles

Gravimetric and Thermal-Imaging Characterization of Water-Free Reflux Condensers for Laboratory Applications.

Water-free reflux condensers, which use convective cooling from the surrounding air to condense vapors, avoid the need for cooling water, which is more sustainable than water-cooled condensers, and eliminates the risk of flooding, but these devices are newer and less familiar to many chemists, who may never have used them before. To facilitate the shift to water-free condensers, several types of water-free condensers (simple glass tube, Vigreux column, Condensyn, Findenser, and air-cooled Dimroth) were characterized using three different solvents (ethyl acetate, acetone, and tetrahydrofuran) under both gentle and vigorous refluxing conditions to compare their relative performance and determine the condensing capacity/failure point. In addition to experimentally quantifying the performance of each condenser both gravimetrically and via infrared thermal imaging, energy-balance models were developed to gain insight into which factors were most important in driving their performance. Several of the water-free condensers, including the Findenser, Condensyn, and air-cooled Dimroth condenser, were shown to provide suitable performance for most refluxing operations.

Influence of fractional distillation on the yield and quality of biofuels obtained through thermal catalytic cracking of crude palm oil

This paper investigates the influence of the fractional distillation on the yield and quality of biofuels obtained in a laboratory unit (Vigreux column) at atmospheric pressure, producing three distilled fractions: (1) green gasoline, (2) green aviation kerosene, and (3) green diesel. The quality of the distilled fractions was evaluated through physical-chemical analysis, FTIR spectroscopy, and GC-MS analysis. The fractional distillation of the crude biofuel provided biofuels in the form of distilled fractions with most values of physical-chemical properties within the limits established by national and international regulatory agencies and with experimental distillation curves similar to standard distillation curves. GC-MS analysis showed that the three distilled fractions had higher contents of hydrocarbons than oxygenated compounds and contained hydrocarbons characteristic of petroleum derivatives such as gasoline, aviation kerosene, and diesel.

Continuous extraction of phenol and cresols from advanced pyrolysis oils

Production of value-added chemicals will ultimately enable commercialization of biofuels. While bio-oils contain phenolic compounds, their separation has generally been difficult due to very wide product distributions. Advances in pyrolysis have produced oils with low oxygen and narrow product distributions that have made separation processes possible. We have demonstrated the continuous extraction of phenolic compounds from fast pyrolysis oils from switchgrass, produced using catalytic and/or tail-gas reactive pyrolysis, which enables distillation due to the absence of unstable oxygenated compounds. Having successfully distilled the bio-oil, the distillate was first subjected to batch extraction with 10 M KOH in varying ratios, and the yields of phenol and cresols were measured. Extraction yields of 15–20 wt% produced extracts where the proportion of measured phenolics consisted of > 50% phenol (i.e. “phenol selectivity”), an increase from 36% in the starting distillates. Washing the distillates with sodium bicarbonate before phenolic extraction helped to reduce excessive acid contamination. Countercurrent continuous extraction experiments using a Vigreux column attained steady-state after only a few minutes, although the phenol selectivity continued to increase for the duration of most experiments. Extraction yields ranged from 15 to 40 wt%.

Volatile aroma composition of distillates produced from fermented sweet and acid whey

Lactose within whey can be fermented and distilled to produce a potable distilled spirit. The aim of this study was to determine if acid and sweet whey types can be fermented and distilled using similar processes and to investigate differences in volatile aroma compounds for the 2 distillates. Fermentation and distillation of the 2 whey types progressed in a similar manner, using Kluyveromyces marxianus for the initial fermentation and a glass still fitted with a Vigreux column for the subsequent distillation. Ethanol content of the wash (fermented whey) varied considerably following each fermentation and ranged from 1.2 and 2.0% (wt/wt) with no clear trend between acid and sweet whey samples. Volatile aroma compounds were extracted using headspace solid-phase microextraction and identified via gas chromatography-mass spectrometry. Acid and sweet whey distillates contained unique volatile aromatic compounds, and significant differences in compound peak areas were observed. These differences may have an effect upon the organoleptic qualities of spirits produced from whey; therefore, whey source may be an important factor when fermenting and distilling whey.

An alternative method based on enzymatic fat hydrolysis to quantify volatile compounds in wheat bread crumb

An alternative method to quantify 40 volatile compounds in wheat bread crumb is proposed. It consists of a Soxhlet extraction with a mixture of dichloromethane and diethyl ether containing lipases and a subsequent concentration with Vigreux column. It is the first time that lipases are added to transform the fat into free fatty acids and glycerol, which elute at the end of the chromatogram after the analytes, avoiding problems in the chromatography due to fat residues, such as dirtiness in the injector, column clogging or overlapping peaks. The extract is most easily analysed by GC/MS, using a standard addition method to correct matrix effect. The method was fully validated, with extraction efficiencies between 70% and 100% and precision RSD lower than 15%. The method was applied to a commercial crumb, with acetoin, phenylethyl alcohol and acetic acid as highly abundant compounds, which are considered main volatiles in crumb.

Equilibrio líquido-vapor del sistema n-hexano – ciclohexano y su separación por destilación fraccionada

El artículo presenta los datos experimentales del equilibrio líquido-vapor del sistema binario n-hexano-ciclohexano a 760 mmHg de presión y su posterior separación por destilación fraccionada, empleando dos columnas diferentes, una de anillos Rasching, otra tipo Vigreux. Los resultados del equilibrio muestran algunas diferencias al compararlos con los obtenidos considerando la disolución con un comportamiento ideal. La columna empacada con anillos Rasching presentó mejor eficiencia en la separación del sistema, pero con un número de platos teóricos mayor que la columna Vigreux aplicando el método de McCabe-Thiele.

Production of green diesel by thermal catalytic cracking of crude palm oil (Elaeis guineensis Jacq) in a pilot plant

In this work, the production of light diesel like fractions by thermal catalytic cracking of crude palm oil (Elaeis guineensis, Jacq.) has been systematically investigated in pilot scale. The cracking reactions were carried out in a reactor of 143L, operating in batch mode at 450°C and atmospheric pressure, using 20% (w/w) sodium carbonate (Na2CO3) as catalyst. The reaction products called organic liquid products (OLP) were submitted to distillation using a laboratory scale column (Vigreux Column) of three stages in order to obtain light diesel like fractions. The catalyst has been characterized by X-ray diffraction, FTIR spectroscopy, TGA and DTG. The OLP and the green diesel fractions have been physical–chemical characterized by officials AOCS, ASTM, and ABNT/NBR methods in terms of acid value, saponification value, density, refraction index, kinematics viscosity, copper strip corrosion, carbon residue, flash point, and distillation curve. The chemical composition of green diesel has been determined by FTIR spectroscopy and GC–MS. The results show that the process yield on OLP was 65.86% (w/w) with an acid value of 1.02mg KOH/g OLP and kinematic viscosity of 1.48mm2/s, 30.24% (w/w) non-condensable gases, 2.5% (w/w) water, and 1.4% (w/w) coke. The yield on green diesel obtained by distillation average 24.9% (w/w), presenting an acid value of 1.68mg KOH/g green diesel and kinematic viscosity of 1.48mm2/s. The GC–MS analysis indicated that green diesel is composed of 91.38% (w/w) of hydrocarbons (31.27% normal paraffins, 54.44% olefins and 5.67% of naphthenics), and 8.62% (w/w) of oxygenates compounds.

Analisis Komponen Aktif Cita-Rasa Pada Susu Fermentasi Dengan Kromatografi Gas

(Active component analysis of fermented milk flavor by gas chromatography)ABSTRACT. Fermented milk is milk processed product that to be one source of nutritious food for humans. The action of food component such as flavor is accepted, sense of taste and smell generated complex assessment of food flavors in the mouth. The flavor components of fermented milk together and interact with each other when consumed and cause the perception of taste between like or dislike. This is an important factor in developing diversification of fermented milk product so as to attract customers other than in terms of aspects of nutrition and health. Flavor is one of the most important criteria in the acceptance of a food ingredient. During processing and storage flavor change easily. This study used gas chromatography to detect the formation of the active component of the flavor of fermented milk. The purpose of this study was to determine the active components in fermented milk which is the formation of flavor. This research was conducted in the Laboratory of Animal Feed Laboratory of the Faculty of Agriculture and Food Chemistry Unsyiah and PAU Food and Nutrition IPB Bogor. This study uses a Likens - Nickerson distillation stage concentrated with Vigreux column and identified by Gas Chromatography Mass Spectrometer. Gas chromatography has identified that the class of acids, alcohols, esters and alkanes group forming an active component in the flavor of fermented milk although relatively varied. In yoghurt, acid found in relatively high amount of alcohol is more varied in its kind. Yogurt with single culture L.bulgaricus has more ketones and aldehydes components. Volatile components were detected mostly in kefir acids, alcohols, esters and alkane derivatives. The curd is dominated by acidic components in addition to alcohol and aldehyde.

Introducing a Novel and Highly Efficient Water-Saving Condenser

A novel prototype condenser has been constructed utilizing a Vigreux column surrounded by a water jacket that is encased in a finned aluminum tube. The results reported demonstrate the possibility of condensing a variety of solvents at low to medium volumes without the need for a continuous flow of water.

AN INNOVATIVE PROJECT INVOLVING AN APPROPRIATE HYBRID DISTILLATION SYSTEM FOR SMALL-SCALE ETHANOL FUEL PRODUCTION

A yield increase in the distillation step reveals a promising way to guarantee technical and economic feasibility for small-scale ethanol production (SSEP), up to 30 L · h−1. The objective of this study is to assess a differentiated distiller, a hybrid composition involving a Vigreux column and a packing (Raschig rings) column in the stripping and rectifying sections, respectively. To evaluate the distiller, seven tests were performed in a continuous operation system. The feed and vaporization rates were varied so that their influence on the operational performance of the distiller could be measured. Specifically, the ethanol concentration in the distillate and bottom products, the operational capacity, and the energy factor were measured. The results prove the technical feasibility of the hybrid distiller, and the application of the hybrid distiller in small-scale distilleries is promising. To improve the distillation step, construction of a pilot-scale column is recommended.

“In situ” extraction of essential oils by use of Dean–Stark glassware and a Vigreux column inside a microwave oven: a procedure for teaching green analytical chemistry

One of the principal objectives of sustainable and green processing development remains the dissemination and teaching of green chemistry in colleges, high schools, and academic laboratories. This paper describes simple glassware that illustrates the phenomenon of extraction in a conventional microwave oven as energy source and a process for green analytical chemistry. Simple glassware comprising a Dean-Stark apparatus (for extraction of aromatic plant material and recovery of essential oils and distilled water) and a Vigreux column (as an air-cooled condenser inside the microwave oven) was designed as an in-situ extraction vessel inside a microwave oven. The efficiency of this experiment was validated for extraction of essential oils from 30 g fresh orange peel, a by-product in the production of orange juice. Every laboratory throughout the world can use this equipment. The microwave power is 100 W and the irradiation time 15 min. The method is performed at atmospheric pressure without added solvent or water and furnishes essential oils similar to those obtained by conventional hydro or steam distillation. By use of GC-MS, 22 compounds in orange peel were separated and identified; the main compounds were limonene (72.1%), β-pinene (8.4%), and γ-terpinene (6.9%). This procedure is appropriate for the teaching laboratory, does not require any special microwave equipment, and enables the students to learn the skills of extraction, and chromatographic and spectroscopic analysis. They are also exposed to a dramatic visual example of rapid, sustainable, and green extraction of an essential oil, and are introduced to successful sustainable and green analytical chemistry.

Home Made Gas Liquuid cromatography Apparatus

A gas-liquid chromatography apparatus which produces a single peak for each component of mixtures is very useful when separating multicomponent systems. Since commercial gas-liquid chromatography Instruments complete aretooexpensive,the home-made apparatus was construc- ted in order to reduce the cost. The flame ionization detector was prepared and calibrated for quantitative analysis of the ternary system of Benzene, Methyl cyclopentane and n-Hexane. The calibration of the detector was obtained by taking peak height rather than the peak areas in con- sideration. Reproducibility of results were in the order of i 0.1 mole percent. The home-made chromatography apparatus was used with confidence to analyse the ternary distillation samples taken from the 1” Vigreux column.

Naturally occurring monoterpenoids in needles of Picea abies (L.) Karst

An analysis was made of the effects of different sampling and extraction techniques on the amounts and pattern of monoterpenoids isolated from needles of Norway spruce. The following isolation and analysis procedure was finally adopted: liquid nitrogen-cooled needles were pulverized by a microdismembrator, extracted with pentane overnight at 2°–3°C and concentrated to a volume not less than 3 ml/g fresh weight on a Vigreux column. The crude extract was injected splitless (with solvent split) onto a cold programmed temperature vaporized (PTV) precolumn of a gas chromatograph and the vaporizable compounds heated to a capillary column. This method was tested for production of artefacts and quantitative extraction and applied to needles of eleven 80-year-old spruce trees.

Aroma components as discriminating parameters in the chemometric classification of venetian white wines

AbstractTwenty‐two volatile aroma components of three Venetian white wines (vintage of 1981) were determined by capillary gas chromatography, after liquid‐liquid extraction and concentration in a Vigreux column. Multiple discriminant analysis and the k‐nearest neighbour rule were applied to data in order to differentiate and classify the wines according to origin. Using 11 selected parameters (alcoholic and acidic fractions), the correctly classified cases were 94.9% by the multiple discriminant analysis, and 71.8% by the 3‐nearest neighbour rule.

1,3-Dimethyl-2,9-dioxabicyclo[3.3.1]nonane; A host-specific substance in Norway spruce under attack byTrypodendron lineatum Oliv.

The isolation and identification of the title compound was carried out in the following manner: Twenty kilograms of the bark from T. lineatum-infested Norway spruce were collected and put directly into pentane after the entrance holes of boring beetles were thoroughly cut out. After standing for 72 h at room temperature the solvent was removed through a 1-m Vigreux column and the residue was distilled under N z at 15Torr. All volatiles up to 100 ~ were collected, yielding 5.2 g of mainly monoterpene hydrocarbons, oxidized monoterpenes, and sesquiterpene hydrocarbons. GLC analysis was carried out on a Carto-Erba 2100, using a 50-m stainless steel capillary column with Marlophen 87 under program from 50 to I40 ~ at a rate of 3 ~ mass spectra were obtained from a Varian MAT 111 GCMS coupling system. A trace substance (0.2Zo) eluting between 7-terpinene and terpinolene furnished a mass spectrum which strongly resembled the known 1-methyl-6,8dioxabicyclo[3.3.1]octanes [1, 2]: 43 (100), 54 (11), 55 (12), 58 (22), 67 (11), 68 (16), 71 (26), 81 (12), 87 (40), 114 (28), 156 (6, P). Preparative GLC on a Carlo-Erba 2400 with a stainless steel column (8 m, 8 mm i.D., 10% PPG on Chromosorb G AW-DMCS 60-80 mesh) yielded 0.2 mg of the substance, the IH-NMR spectrum (Bruker WH 270, 15,000 scans) of which showed two characteristic signals at b 4.09 (1 H) and 4.21 (1 H), suggesting a bicyclic ketal structure together with the molecular formula C9H1602, obtained by high-resolution mass spectrometry (Varian MAT SM 1). None of the probable 6,8-dioxabicyclo[3.2.1]octane structures which were prepared for comparison were completely in accord with all data of the natural compound. But 1,3-dimethyl-2,9-dioxabicyclo[3.3.1]nouane, a ketal belonging to a bicyclic system recently found in tobacco flavor [3], was identical in all respects with the natural compound. The substance was prepared in low yield by Diels-Alder reaction of 3-buten-2-one and 4-penten-2-ol followed by cyclization. Results of our investigations concerning the exact stereochemistry will be reported later. As the new compound is permanently and exclusively present in Norway spruce attacked by I". lineatum it is now l~ioassayed to clarify whether it serves as a primary attractant beside other chemical messengers such as 3hydroxy-3-methylbutanone [4, 5] and c~-pinene/ethanol [6].

Alkyl azelaaldehydates of high purity from alkyl soyates: Preparation and properties

AbstractReductive ozonolysis of appropriate alkyl soyates in various participating media producted methyl, ethyl,n‐propyl, isopropyl andn‐butyl azelaaldehydates in good yield and high purity (98+%). The participating media examined were: methyl, ethyl,n‐propyl andn‐butyl alcohols; mixtures of an alcohol and acetic acid; water; and mixtures of water and acetic acid. Any combination of solvent and ester, except methanol‐methyl soyate, allowed good separation by fractional distillation of ester and acetal impurities from the azelaaldehydate. A preparative method was developed by which high purity ethyl azelaaldehydate is produced from soybean oil by reductive ozonolysis in water. The only major impurity by this method was ethyl hydrogen azelate, which was easily removed with a bicarbonate wash. After a single fractional distillation with a short Vigreux column, the azelaaldehydate was obtained in 78% yield and 98+% purity. Physical properties and spectral (IR, NMR and mass spectroscopy) and chromatographic data were determined for the pure alkyl azelaaldehydates. Several of these properties were also determined for acetal and diester byproducts.

Refractive indices of monomer-polymer mixtures of vinyl formate, vinyl acetate, vinyl propionate, and vinyl butyrate

Monomers of vinyl formate, vinyl acetate, vinyl propionate, and vinyl butyrate were carefully purified by distillation in a Vigreux column and in a 56-plate glass helixpacked Todd column. The refractive indices and boiling points of the purified monomers agreed with those given in the literature. The purified samples were exposed to the radiation of a quartz mercury lamp in order to produce several per cent polymer. The refractive indices are tabulated and plotted in graphs.

Vacuum distillation II: Performance of a Vigreux column and a spinning band column over a wide range of pressures

Performance figures referring to a 11 mm diameter Vigreux column and a 6 mm diameter spinning band column over a pressure range of about 0·13 kN/m 2–101·5 kN/m 2 (about 1–760 mm Hg) are presented. In order to gain an insight into the mechanisms of material transfer involved, analyses of separate vapour and liquid phase resistances were made. In the case of the Vigreux column it was found that liquid phase resistance was about half the total resistance at atmospheric pressure. A reduction in pressure causes the liquid phase resistance to be increased by increasing liquid viscosity on the one hand and to be decreased by the higher vapour rates on the other hand. These two compensating factors cause a total efficiency loss of the Vigreux column of about 25% when the pressure is reduced from atmospheric value to about 0·13 kN/m 2 (1 mm Hg). at this top pressure the maximum pressure drop along the Vigreux section is about 0·3 kN/m 2 (3–4 mm Hg) per metre. In a spinning band column the main resistance to material transfer is offered by the vapour phase. This resistance is reduced by creating turbulence through rotation of the spinning band. The present study disclosed the existance of two limiting values of rotational speed: a lower limit below which rotation does not yet cause turbulence, and a higher limit above which back mixing in the liquid phase causes the separating power to be independent of—or to decrease with—speed of rotation. Due to the fact that the extent to which turbulence can be effected in the vapour phase proves to depend on rotational speed and vapour density to the same degree, the sensitiveness to pressure variations of the spinning band column is rather great. Reduction of the pressure from atmospheric value to about 1·3 kN/m 2 (10 mm Hg) causes an efficiency loss of about 70%; in fact at this pressure the separating power of the spinning band column was not better than that of a wetted wall column of the same dimensions.