Alkaline Emulsion Research Articles

Preliminary Studies on the Electrochemical Conversion of Liquefied Forest Biomass

Bio-oils produced from three different biomass sources, namely cork, pinewood, and olive stones, are evaluated concerning their suitability and prospects of including their electrochemical transformations in a biorefinery scenario for the production of added-value compounds. Different types and concentrations of electrolytes (e.g., H2SO4, KOH) are added to the bio-oils to increase the samples’ initially low ionic conductivity. The samples prepared by mixing bio-oil with 2 M KOH aqueous solution (50 vol.%) lead to a stable and homogeneous bio-oil alkaline emulsion suitable for electrochemical studies. The bio-oil samples are characterized by physicochemical methods (e.g., density, viscosity, conductivity), followed by analyzing their electrochemical behavior by voltammetric and chronoamperometric studies. The organics electrooxidation and the hydrogen evolution reaction in the bio-oils are assessed using Pt electrodes. Single- and two-compartment cell laboratory bio-oil electrolyzers are assembled using nickel plate electrodes. Electrolysis is carried out at 2.5 V for 24 h. Attenuated Total Reflection-Fourier-Transform Infrared Spectroscopy and Mass Spectrometry are applied to identify possible changes in the bio-oil samples’ chemical structure during the electrolysis experiments. Comparing the analyses of the bio-oil samples subjected to electrolysis with the blank samples demonstrates that bulk electrolysis significantly changes the bio-oil composition. The bio-oil obtained from cork biomass shows the most promising results, but further studies are required to understand the nature of the actual changes.

Improving the Anti-Pilling Performance of Cellulose Fiber Blended Knitted Fabrics with 2,4,6-Trichloropyrimidine Treatment

Pilling is a common and unresolved problem in knitted fabrics, especially for the cellulose fiber blended fabrics, which not only causes an unattractive appearance and an uncomfortable handle, but also reduces the added value of the products. In this study, four different kinds of knitted fabrics were treated with 2,4,6-trichloropyrimidine (TLP) alkaline emulsion by dipping and pad–dry–cure modification processes. The surface morphology and chemical structure of original and treated fabrics were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The anti-pilling performance, thermal properties, physical and mechanical properties and color features of treated fabrics were also evaluated. The results indicated that TLP was successfully covalently crosslinked onto the surface of the cellulose fibers. The dipping process resulted in a better anti-pilling property than that of the pad–dry–cure process, and both treatments could bring about an excellent anti-pilling property and outstanding laundering durability. A pilling grade of 4.5 was achieved for the treated polyester/viscose (T/V) fabric with the dipping process even after 20 washing cycles. In addition, the treated fabrics displayed an enhanced antistatic property and still maintained a soft handle. Besides, the bursting strength and air permeability of treated samples were found to have a slight deterioration, while no apparent differences were found in the color parameters and colorfastness of dyed fabrics. The above results demonstrate that 2,4,6-trichloropyrimidine has the potential application prospect in the functional finishing and home-caring of textiles.

Time and energy reduction on grape dehydration by applying dipping solution on freeze drying process.

To reduce energy expenditure, dehydration processes are being improving by pretreatments and changing frozen stage. Alkaline emulsion pretreatment was introduced to freeze-drying method to reduce the drying time of grapes and obtain significant energy savings. Dehydration process for untreated fresh grape samples was 22 hours, using industrial freeze-drying equipment. It was obtained a high quality product with range 3 % to 7% of final humidity, without losing natural characteristics and organoleptic properties of the grapes. it was found by modifying standard equipment frozen method, using dry ice (CO2) and applied coconut oil alkaline emulsion pretreatment, a 54% energy saving. Even more the dehydration process decreased the microbial load in the fruit. A product with low number of microorganisms may be consumed by patients with low defenses as cereals, nutritional bars, salads, yogurts, etc. Finally, if all enterprises involved in this field take into account these findings and improve constantly their process they will stop emitting several kg of CO2 into the atmosphere.

Sensory Analysis of Sweet Musts in Pedro Ximenez cv. Grapes Dried using Different Methods

The sensory properties of musts from Pedro Ximenez grapes chamber-dried at 40 or 50°C, with or without a dipping treatment, are compared to musts from grapes subjected to the traditional sun-drying method used in the production of sweet wines. The chamber-dried procedure, specifically at 50°C, decreased the drying time, improved the health status of the grapes relative to the growth of fungi that produce toxins and yielded must with a very similar color to that of sun-dried grapes. Sensory evaluation has shown that must from grapes dried at 50°C, after treatment with an alkaline emulsion of ethyl oleate, is unacceptable due to the light color. The musts receiving the highest scores for color, aroma and flavor were from untreated grapes dried at 50oC or potassium carbonate-treated grapes dried at the same temperature. However, the treatment did not significantly accelerate drying.

Biodegradation of chemically modified lignocellulosic sisal fibers: study of the mechanism for enzymatic degradation of cellulose

AbstractThe susceptibility and characteristics of biological degradation of lignocellulosic fibers, such as sisal fibers, are presented in this study using a modified soil burial test (SBT) protocol. The biodegradation profile of untreated sisal fibers as well as of fibers treated with an alkaline emulsion of neem oil and phenolic resin was evaluated by estimating the enzymatic activities during the exposure of fibers to a soil/compost mix. Observation of the results indicated that biodegradation of the fibers was predominated by enzymatic hydrolysis of amorphous materials followed by degradation of crystalline cellulose. It was also evident that “oil-resin” treatment makes the fibers more resistant to biodegradation owing to the removal of amorphous materials, enhanced hydrophobicity, and possible chemical alteration of the surface hydroxyl groups of the fiber surface. This research aims to establish a systematic knowledge on the biodegradation profile of fiber components using a state-of-the-art protocol for SBT.

Effect of carbonic maceration on infrared drying kinetics and raisin qualities of Red Globe (Vitis vinifera L.): A new pre-treatment technology before drying

Abstract Effects of carbonic maceration (CM), dipping in alkaline emulsion of ethyl oleate solution (AEEO) and dipping in AEEO then freezing at − 18 °C for 12 h (AEEO + Freezing) on infrared drying kinetics of red grapes and properties of raisins were investigated. The results indicated that the raisin of CM treated samples had the shorter production time, the highest total phenol content, the best oxidation resistance ability, and the best rehydration ratio, which increased by − 31%, 28.43%, 73.9% and 32.24%, respectively, as compared to the raisins from fresh samples. CM treated samples had the greatest incremental of lenticel size, followed by AEEO + Freezing and AEEO samples. The bigger the lenticel size, the greater was the drying rate. Industrial relevance The carbonic maceration (CM) technique before drying – a new pre-treatment technology presented in this paper – can greatly increase the drying rate and improve the quality of products, meanwhile, it is free of any chemical reagents, which is friendly to the environment. So CM process technology prior to drying is of commercial potential if it is used in industry.

Geopolymer with Hierarchically Meso‐/Macroporous Structures from Reactive Emulsion Templating

We present a simple synthetic route to hierarchically porous geopolymers using triglyceride oil for a reactive emulsion template. In the new synthetic method, highly alkaline geopolymer resin was first mixed with canola oil to form a homogeneous viscous emulsion which was then cured at 60°C to give a hard monolithic material. During the process, the oil in the alkaline emulsion undergoes a saponification reaction to be decomposed to water‐soluble soap and glycerol molecules which were then extracted with hot water to finally yield porous geopolymers. Nitrogen adsorption studies indicated the presence of mesopores, whereas the SEM studies revealed that the mesoporous geopolymer matrix are dotted with spherical macropores (10–50 μm) which are due to oil droplet template in the emulsion. Various synthetic parameters including the precursor compositions were examined to control the porosity. BET surface area and BJH pore volume of the materials were up to 124 m2/g and 0.7 cm3/g, respectively, and the total pore volumes up to 2.1 cm3/g from pycnometry.

Effect of air temperature, slice thickness and pretreatment on drying and rehydration of tomato

SummaryThe effect of air temperature, pretreatment with alkaline emulsion of ethyl oleate (AEEO) and slice thickness on drying and rehydration characteristics of tomato slices was studied. Drying time decreased with pretreatment, but it increased considerably with the increase in air temperature and slice thickness of tomato. Besides, pretreatment was found to improve the rehydration ratio of tomato slices. The experimental drying curves obtained show only falling rate period. To estimate and select the suitable form of drying curves, five different mathematical models were applied to the experimental data. Among the mathematical models investigated, the Midilli et al. and logarithmic models satisfactorily described the drying characteristics of tomato slices with highest R2 and lowest χ2 and root mean square error. The effective moisture diffusivity varied from 3.123 to 10.03 × 10−11 m2 s−1 over the temperature range studied, and the activation energy values varied from 59.6 to 70.2 kJ mol−1.

Preparation of spherical silica in emulsion systems using the co-precipitation technique

Silica powders with particles of spherical shape and a low tendency to agglomeration of primary particles have been prepared by precipitation from sodium metasilicate and hydrochloric acid via the emulsion technique. The organic phase of the emulsion system was cyclohexane while a non-ionic surfactant was applied as an emulsifier. In the course of silica precipitation three alternative ways of dispersion induction were applied: the top stirrer, homogenization and ultrasounds. The precipitation was performed at three temperatures (25 °C, 40 °C and 60 °C), using different variants of dosing schemes of the emulsion and the aqueous solutions of substrates. Homogenization of the reactive system yielded silica of spherical particles of the lowest mean particle diameter and the most uniform character. The only appropriate mode of dosing the reagents to the emulsion was the introduction of alkaline emulsion to acidic emulsion. A decreased tendency for silica particles agglomeration could be achieved by increasing the volume of the organic phase in the emulsions prepared. The optimum temperature for the precipitation reaction was 25 °C. The procedure permitted obtaining in SiO 2 particles of the optimum diameter (<1 μm) and particles of spherical shape. Moreover, the silica adsorbents obtained manifested high activity. Their surface area reached values in the 340–390 m 2 g −1 range.

Influence of dipping on thin-layer drying characteristics of seedless grapes

The drying characteristics of pretreated seedless grapes were studied using a laboratory-scale tray dryer with the air temperature varied from 40 to 70 °C at air velocity of 1 m s −1 . The effective moisture diffusivities were determined using an analytical–numerical solution method considering shrinkage, while variable thermal diffusivity was calculated from experimentally estimated values of thermo-physical properties at a given moisture contents. These parameters were correlated with the corresponding moisture content and temperatures in an empirical model using a non-linear regression method. This shows that the seedless grapes of the same clone vines, as subjected to the hot water (HW) and alkaline emulsion of ethyl oleate (EO) pretreatments, exhibited average effective moisture diffusivities that ranged from 3.34 to 8.46×10 −10 m 2 s −1 at 50 °C. The increase in mass transfer coefficients at a given moisture content at different temperatures for the EO-pretreated samples was two times that for the HW-pretreated samples during the drying. However, the pretreatments had no the significant effect on the thermal diffusivities of the grapes during the drying.

Hot-air drying characteristics of red pepper

This work presents a theoretical and experimental study of the drying kinetics of red peppers under different pretreatment and air drying conditions. Red peppers, Capsicum annuum, grown in the region of Kahramanmaras, Turkey, were pretreated with various solutions of alkaline emulsion of ethyl oleate (AEEO) and dried afterwards. To date, there has been no work that studied the effect of AEEO pretreatment solution on the drying of red peppers. Our results indicated that pretreated peppers dried faster and had higher Hunter L (lightness), + a (redness) and + b (yellowness) values than the untreated and dried peppers. 2% ethyl oleate and 5% K 2CO 3 solution was found to be the most effective dipping solution that provided for whole peppers dried at 50 °C, and yielded best color quality. Drying curves of sliced peppers were obtained using the Page and exponential equations. Comparing the r 2 values of both equations, it was concluded that the Page equation represents drying characteristics better than the exponential equation.

The effects of dipping pretreatments on air-drying rates of the seedless grapes

Turkey has a significant potential for fruit and vegetable production. Grape is an economically important item for Turkey's export. However, problems encountered during drying of grapes have not yet been resolved. The effects of different dipping solutions on hot air drying of grapes were studied. Seedless grapes pretreated with alkaline emulsion of ethyl oleate (AEEO) resulted in comparatively good quality raisins. Grapes dipped into ethyl oleate solution prior to drying showed shorter drying times than those untreated, or pretreated with potassium carbonate solution. Colour analysis of grapes showed that the best results are obtained in grapes which were pretreated with an AEEO and dried with air at 60 °C. The drying rates of grapes were modeled by the Page and Exponential equations. The model results agreed with experimental results.

A Study on Drying Characteristics of Kahramanmaras Red Pepper

Red peppers are one of the main agricultural product in Turkey. In peppers drying experiments, red peppers grown in Kahramanmaras region were used. In this experiments, solution of Alkaline Emulsion of Ethyl Oleate (AEEO) pretreatment was used, firstly. In order to determine the effect of the composition of pretreating solution, various solutions were prepared and used. Among these solutions, 2% AEEO+5% K2CO3 solution has led to the fastest drying rate. A better quality was obtained at lower air temperatures but with longer drying time. Pretreated peppers got dried faster than the ones dried naturally. Colour analysis showed that red colour was preserved better in peppers pretreated with AEEO solution than those dried naturally. From the data obtained, drying curves of peppers were plotted using Page and Exponential equations. Coefficients of determination (r2) of these equations were also given. r2 of Page equation is higher than r2 of Exponential equation.

Effects of varying the method of applying alkaline emulsion on the drying of Sultana grapes

AbstractSultana berries were treated with alkaline oil‐in‐water emulsion by partial or total immersion, spotting or spraying. Their weight loss during dehyration at 40°C and the colour and extent of surface bloom of the resultant raisins were determined. Approximately 37 μl of emulsion adhere to the berry during immersion but about 85% of this accumulates as a run‐off droplet. Spread of emulsion from treated to untreated parts occurs on mature berries only; it increases with increasing maturity, as shown by its linear relationship with the concentration of total soluble solids in the fruit. Comparable amounts of emulsion are more effective when spotted uniformly instead of distally on the berry surface. Drying accelerates as berries receive more spots of emulsion. Approximately 9 μl of emulsion placed by spotting or part‐immersion give raisins of similar quality to that of raisins dried after total immersion, despite slower drying rates during the first 36–48 h of dehydration. Any further reduction in the amount of emulsion leads to slower drying and darker raisins.The spray emitted by the nozzels used contained droplets of 190 or 440 μm mean diameter. Between 0.5 and 1.5 μl of emulsion was applied per berry. Small droplets were about 20% more effective than large ones. The efficacy of the best spraying treatment, 1.5 μl berry−1 and small droplet size, was almost as good as that of immersion.It is concluded that the efficacy of emulsion treatment depends in part on the characteristics of the fruit to be dried. Comparisons between treatments should only be made from several measurements during the course of drying. The cost of drying may be reduced and the quality of the raisins may improve when the emulsion treatment is modified according to the type of Sultana berry to be dried.

Electrolytic Process for the Preparation of Dianisidine Using Rotating Cathode Cell for the Reduction of o-Nitroanisole to Hydrazoanisole

Abstract The technique of using rotating cathodes for electrolytic reduction of nitro compounds developed in this Institute earlier has now been extended to the study of the reduction of o-nitroanisole in an alkaline emulsion to obtain hydrazoanisole, which is subsequently converted to dianisidine by reaction with acid. The various chemical methods of obtaining hydrazoanisole as well as the previous attempts for obtaining the same by electrolytic reduction of o-nitroanisole are briefly reviewed. The experimental technique adopted, the isolation of the product and the subsequent conversion of the hydrazoanisole to dianisidine are described. Cathode potential has been measured at different current densities using lead deposited iron cathode under stationary and rotating condition of the cathode without the addition of nitro compound. The effect of the nitro compound addition on the cathode potential at different current densities has also been studied. The potential of a rotating cathode measured during the course of an experiment is graphically presented and the results discussed.

Effect of Agitation on the Electrolytic Preparation of Hydrazobenzene from Nitrobenzene in Alkaline Emulsion and the Effect of Agitation on Electrolytic Reduction of Organic Compounds in Emulsifying State

Effect of Agitation on the Electrolytic Preparation of Hydrazobenzene from Nitrobenzene in Alkaline Emulsion and the Effect of Agitation on Electrolytic Reduction of Organic Compounds in Emulsifying State

Electrolytic Reduction of Nitrobenzene to Hydrazobenzene

In small scale experiments on the electrolytic preparation of hydrazo‐benzene from nitrobenzene in alkaline emulsion it was found that cathodes of zinc, tin, cadmium, and lead with more than 0.07 mole of spongy layer per square decimeter of the surface were most suitable for the reduction. As base materials for the spongy layers, common metals such as Pb, Fe, and others were found to be useful. At these cathodes, almost quantitative yields of hydrazobenzene were obtained at relatively high current densities with suitable agitation. The mechanism is believed to consist of true electrochemical reduction of nitrobenzene to azoxy‐ or azobenzene, followed by further chemical reduction of the azobenzene by sponge metal. The mechanism gains support from results of polarographic measurements which show that, while nitrobenzene is an active depolarizer with or without organic solvent in the catholyte, azobenzene is active only when a solvent such as alcohol is present.In the interest of developing a practical electrochemical preparation of hydrazobenzene, preliminary runs have been made in a larger cell using 1.5 kg of nitrobenzene; material yields of hydrazobenzene up to 90% and current efficiencies of 80% at 17 amp/dm2 have been obtained, compared with yields of 95% and efficiencies as high as 88% at 30 amp/dm2 obtained with the small cell.

The Structure of Neoprene. II. Determination of End Groups by Means of Radiosulfur

Abstract By use of radioactive sulfur it has been shown that sulfur-modified Neoprene, i.e., Neoprene Type GN, is essentially a copolymer of chloroprene and sulfur in the approximate ratio of 100 chloroprene units per sulfur atom. The sulfur units, possibly disulfides, are cleaved by an alkaline emulsion of tetraethylthiuram disulfide, so that a gel polymer containing combined sulfur can thus be converted to a soluble, plastic product. The mechanism of this cleavage reaction has not been completely elucidated as yet. Potassium persulfate, used as initiator for the polymerization of Neoprene, appears to be combined with the polymer in Neoprene Type GN in amounts equivalent to 8–17 polymer molecules formed for each sulfur-cpntaining initiator fragment. However, when dodecanethiol is used as modifier, a large proportion of the polymer molecules contain essentially no combined sulfur from the persulfate, and it appears that the true initiator is the RS free radical formed by reaction of the thiol with potassium persulfate. Dodecanethiol used as a polymerization modifier or chain transfer agent is combined in a greater amount than the one thiol per polymer molecule expected on the basis of simple chain transfer. High molecular-weight fractions contained 3–4 thiol sulfur atoms per polymer molecule and the results suggest that thiol addition to the double bonds of the polymer had occurred.

The Structure of Neoprene. II.1 Determination of End-Groups by Means of Radiosulfur

Abstract By use of radioactive sulfur it has been shown that sulfur-modified Neoprene, i.e., Neoprene Type GN, is essentially a copolymer of chloroprene and sulfur in the approximate ratio of 100 chloroprene units per sulfur atom. The sulfur units, possibly disulfides, are cleaved by an alkaline emulsion of tetraethylthiuram disulfide, so that a gel polymer containing combined sulfur can thus be converted to a soluble, plastic product. The mechanism of this cleavage reaction has not been completely elucidated as yet. Potassium persulfate, used as initiator for the polymerization of Neoprene, appears to be combined with the polymer in Neoprene Type GN in amounts equivalent to 8–17 polymer molecules formed for each sulfur-cpntaining initiator fragment. However, when dodecanethiol is used as modifier, a large proportion of the polymer molecules contain essentially no combined sulfur from the persulfate, and it appears that the true initiator is the RS free radical formed by reaction of the thiol with potassi...