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  Subjects -> CHEMISTRY (Total: 841 journals)
    - ANALYTICAL CHEMISTRY (50 journals)
    - CHEMISTRY (593 journals)
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CHEMISTRY (593 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 8)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 34)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 18)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 23)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 236)
ACS Photonics     Full-text available via subscription   (Followers: 11)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 21)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 50)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 55)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 14)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 19)
Advances in Nanoparticles     Open Access   (Followers: 15)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 68)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Chemistry     Open Access   (Followers: 26)
American Journal of Plant Physiology     Open Access   (Followers: 14)
American Mineralogist     Hybrid Journal   (Followers: 14)
Analyst     Full-text available via subscription   (Followers: 40)
Angewandte Chemie     Hybrid Journal   (Followers: 224)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 213)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 3)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 15)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 28)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 295)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 19)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 120)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 97)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 3)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 66)
Catalysis for Sustainable Energy     Open Access   (Followers: 7)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 8)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 13)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 70)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 23)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 19)
Chemical Reviews     Full-text available via subscription   (Followers: 177)
Chemical Science     Open Access   (Followers: 22)
Chemical Technology     Open Access   (Followers: 16)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 8)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 26)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 142)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 18)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 44)
Chemistry of Materials     Full-text available via subscription   (Followers: 260)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 9)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 7)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 2)
Copernican Letters     Open Access   (Followers: 1)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 3)
CrystEngComm     Full-text available via subscription   (Followers: 12)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 58)
Dalton Transactions     Full-text available via subscription   (Followers: 22)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 4)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 4)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 2)
Environmental Chemistry     Hybrid Journal   (Followers: 8)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)
Environmental Science : Nano     Partially Free   (Followers: 1)
Environmental Toxicology & Chemistry     Hybrid Journal   (Followers: 17)

        1 2 3 | Last

Journal Cover Chemical Technology
  [16 followers]  Follow
    
  This is an Open Access Journal Open Access journal
   ISSN (Print) 1392-1231
   Published by Kaunas University of Technology Homepage  [10 journals]
  • VERIFICATION OF AVAILABLE GLASS MECHANICAL PROPERTIES AGAINST
           RECOMMENDATION BY THE DRAFT EUROCODE DESIGN PRACTICE

    • Authors: L. Sable, K. Kalnins
      Abstract: Glass as a structural material has strongly evolved in modern architecture. Wide windows, glass facades and even load-bearing structures make buildings appear transparent and more integrated in the surrounding environment. According to the ongoing effort by the European Committee for Electrotechnical Standardisation, only recently the notice “Eurocode on glass in construction” has been issued. This will make applicable the binding design practice in the EU starting from the next decade. This design practice will include, among others, the required properties of material and products, application fields, respective failure potential and failure consequences, safety and reliability approaches, principles of design, design and calculation rules for primary members, joints, connections and supports. This standard will be binding in all European countries, therefore, until then every member state should adapt these guidelines in order to make safe design practices for glass structures. At present, in Latvia there is no enforced regulation for glass-bearing structural design and a scattered view on the mechanical properties of the available glass applied for load-carrying designs. In the present verification study, laboratory testings were performed to characterise glass mechanical properties such as stiffness and bending strength of the set of specimens provided by national distributers. For this reason, a series of samples has been tested by a 4-point bending with two different geometrical settings 360 ´ 1100 mm (EN 1228-3) and short beam tests of 50 ´ 200 mm. The current research has shown that compared with the Eurocode reference values, these test results show a lower strength of the internally available raw glass panels. The cause should be merged with edge grinding technology and studied in more detail in the further analysis.
      DOI : http://dx.doi.org/10.5755/j01.ct.68.1.18872
      PubDate: 2017-08-22
      Issue No: Vol. 68 (2017)
       
  • ACCUMULATION OF RESIDUAL ENERGY OF AN EXPERIMENTAL STOVE AFTER BURNING

    • Authors: C. Stone, R. Drab, F. Vranay
      Abstract: Engineers, architects and designers increasingly rely on mathematical constructs incorporated into civil engineering programs to explain physical and mechanical phenomena. A low thermal diffusivity represents a material’s ability to slow down the rate of heat transfer due to heat absorption and storage, so that high thermal masses are desirable. The thermal inertia of the earth structures in general is an under-researched topic, especially regarding their unique ability to delay and attenuate temperature responses. The paper uses a high temperature difference example, in the form of an experimental stove, to highlight the benefits of a thermal mass. Countries such as Austria, the Czech Republic and Slovakia are known for their ornate historical masonry stoves that grace many stately houses, castles and palaces. They were stoked once or twice daily and radiated heat constantly during the winter months. This guild developed and thrived until the advent of modern HVAC systems in the 20th century. The paper sets out to monitor the temperature difference produced by stoking and firing a simplified experimental stove and analyses the decrease in temperature until it approaches a fixed room temperature. Temperature and heat flux are then observed to determine the total residual heat energy after burning, and the results are discussed in the conclusion. Inspired by these sound principles, based on lessons from the vernacular building traditions that have been used for centuries, the output of this work could be used in future to design an appropriate amount of the thermal mass to maximize thermal efficiency in fireplaces and stoves and as a precedent for a synergetic combination of the thermal mass and renewable energy sources.
      DOI : http://dx.doi.org/10.5755/j01.ct.68.1.15006
      PubDate: 2017-08-22
      Issue No: Vol. 68 (2017)
       
  • APPLICATION OF ION-EXCHANGE RESINS FOR REMOVING SULPHATE IONS FROM ACIDIC
           SOLUTIONS

    • Authors: M. Holub, P. Pavlikova, M. Balintova, M. Smolakova
      Abstract: The removal of sulphate ions from different types of wastewater is an environmental challenge faced by several industrial sectors such as the mining, petrochemical or metallurgical industry. Most of the current existing options are inefficient and economically unviable, particularly for acid mine drainage (AMD), where the low pH and high concentrations of heavy metals and sulphates are limiting for these processes. This work is focused on ion-exchange as one of the most common treatment methods for AMD treatment. Ion-exchange represents a very powerful technology where one or more undesirable contaminants are removed from the aqueous environment by exchange with another substance. The ideal ion-exchange solution for sulphate reduction is one that combines both anionic and cationic resins. The paper presents the results from ion-exchange experiments by the synthetic ion-exchange resin and the AMBERLITE MB20 for SO42– removal from a model solution. The efficiency of the AMBERLITE MB20 resin for SO42– removal from the model solution H2SO4 was higher than of the PUROLITE MB400, and its efficiency decreased with increasing the concentration of sulphates from 86.6 % for the concentration 100 mg/L to 66.9 % for the concertation 1000 mg/L.
      DOI : http://dx.doi.org/10.5755/j01.ct.68.1.15004
      PubDate: 2017-08-22
      Issue No: Vol. 68 (2017)
       
  • THE INFLUENCE OF THE SILICA/SODIUM RATIO ON THE FLY ASH GEOPOLYMER BINDER

    • Authors: V. Bocullo, D. Vaičiukynienė, V. Vaitkevičius, A. Kantautas
      Abstract: This article investigates the properties of a geopolymer, an alternative binding material to the ordinary Portland cement (OPC), and their dependence on different SiO2/Na2O ratios in the system. To make the geopolymer polish coal burning fly ash consisting mainly of amorphous SiO2 and Al2O3, it was activated with a NaOH solution. While many researches have been done on the Si/Al ratio influence, not many studies have examined the activator solution influence on geopolymer properties. Samples were made with 8 different mix compositions with the SiO2/Na2O ratio varying within 0.8–3.1. The samples were tested for compressive strength after 7, 14 and 28 days of curing. The mineral composition of each set mix was examined with XRD. Samples with the SiO2/Na2O ratio equal to 2.0 showed the highest compressive strength. The XRD of these samples showed the presence of low-crystallinity hydrosodalite and a small amount of mullite and quartz. The acceptable strength was shown by samples with the SiO2/Na2O ratio in the range of 1.5–2.5. Samples with the ratio beyond this range failed to produce enough of the necessary binding agents.
      DOI : http://dx.doi.org/10.5755/j01.ct.68.1.18873
      PubDate: 2017-08-22
      Issue No: Vol. 68 (2017)
       
  • MANUFACTURING OF LIQUID COMPOUND FERTILIZERS FROM WASTE POTASSIUM
           DIHYDROGEN PHOSPHATE PRODUCTION

    • Authors: K. Jančaitienė, R. Šlinkšienė
      Abstract: In the production of many products in various industries, especially chemical, the positive aspect is the creation and use of a waste-free technology. It has been found that the content of a liquid phase after interaction between NH4H2PO4 and KCl (the molar ratio of the starting materials was 0.8 : 0.2) depends on the conversion temperatures. The chemical composition of the liquid phase can vary from 1.19 to 1.45 % of N, from 14.96 to 26.55 % of K2O, from 1.06 to 2.55 % of P2O5 and from 13.42 to 13.71 % of Cl. The other properties of the solutions, such as pH, density and viscosity, are almost independent of temperature and meet the requirements for liquid compound fertilizers. This means that it is possible to produce a liquid fertilizer 4–5–15 grade in the post-crystallization of potassium dihydrogen phosphate remaining solution (when the molar ratio of the starting materials is 0.8 : 0.2) by adding 6 % of CO(NH2)2 wherein the crystallization temperature is 15 °C. It has been discovered that the liquid fertilizers 4–5–15 grade are efficient and give a bigger yield of plants. It increased the test plate dry weight by 78.2 %, the ash content by 41.6 % and the height of the plants by 31.2 %.
      DOI : http://dx.doi.org/10.5755/j01.ct.68.1.18874
      PubDate: 2017-08-22
      Issue No: Vol. 68 (2017)
       
  • APPLICATION OF SURFACE COMPLEXATION AND ION EXCHANGE MODELLING FOR THE
           ESTIMATION OF BENTONITE SORPTION CAPACITY ON SELECTED RADIONUCLIDES UNDER
           POSSIBLE GEOLOGICAL DISPOSAL CONDITIONS IN LITHUANIA

    • Authors: V. Vaitkevičienė, A. Narkūnienė
      Abstract: Designing a repository for radioactive waste as a multi-barrier system with predefined multiple safety functions provides for the protection of people and environment from the harmful effect of the ionising radiation of radionuclides once released from high-level radioactive waste. The multi-barrier system is comprised of the engineered barrier system (EBS) and its surrounding natural environment. Because of the high retention capacity for the radionuclides, various forms of bentonite are usually considered as a part of the EBS in the design of radioactive waste repositories. Laboratory batch experiments with natural sediments illustrate that the sorption (and Kd values) is sensitive to aqueous chemical conditions, including the pH and the dissolved carbonate concentration as well as the mineralogy and surface area of the bentonite buffer. The cations considered for the study were chosen as covering a representative range of cations behaviour: from a weakly sorbed cation Cs(I) to moderately sorbed cation the Ni(II) and strongly sorbed cation, Eu(III). In this study, a potential retardation of sorbing radionuclides (Cs, Ni, Eu) as a function of aqueous chemical conditions in the groundwater of the Lithuanian crystalline basement contacting the bentonite material was estimated for the first time. The ion exchange and surface complexation models (SPNE/CE) and the computer program PHREEQC (USA) were applied for modelling the interaction within the radionuclide/water/bentonite system. The modelling of the Kd values under different pH conditions and a given partial pressure of carbon dioxide in the gas phase were performed. The highest value of Kd in the pCO2 open system and the strongest sorption dependence on pCO2 was estimated for Eu(I) among radionuclides being studied. There was estimated only a slight change in Kd values with respect to the temperature.
      DOI : http://dx.doi.org/10.5755/j01.ct.68.1.18875
      PubDate: 2017-08-22
      Issue No: Vol. 68 (2017)
       
  • PROPERTIES OF CATIONIC STARCHES OBTAINED BY REACTIVE EXTRUSION

    • Authors: J. Bendoraitienė, E. Lekniutė-Kyzikė, V. V. Litviak, V. V. Moskva
      Abstract: Two different methods, namely chemical and physical modification in the Druvather® reactor DVT5 and Krauss Maffei twin-screw extruder ZE25R x 40D UTXi were used to prepare cationically modified starches, and the properties of those were compared. The reactive extrusion process consisted of two stages. In the first one, the mixture of reaction components at the molar ratio starch : 2,3-epoxypropyltrimethyl-ammonium chloride : NaOH : H2O = 1 : 0.125 : 0.04 : 3.5 was obtained. In the second one, the derived mixture was extruded by using a twin-screw extruder. The extrusion temperature varied from 20 to 140 °C, the screw speed was 50 rpm, and the mixture feed rate was about 1.5 kg/h. Four different samples of extruded cationic starches were obtained. The main characteristics such as the degree of substitution of cationic groups (DS), reaction efficiency, particle size and the polydispersity index were determined and compared with those of a non-extruded control sample of cationic starch of similar DS. Also, the parameters well defining the behavior of samples in water, such as the swelling power (SP) and the solubility index (SOL) at 75 °C were determined for extruded and control samples. It was established that the properties of extruded and non-extruded cationic starches were different. The following observations can be drawn with respect to the obtained data: the particle size of the extruded samples is much lower and the SP values are 7–13 times lower than those of the control sample; the SOL values of the extruded samples are twice as high, reaching 76–92 %, and even might be higher.
      DOI : http://dx.doi.org/10.5755/j01.ct.68.1.18876
      PubDate: 2017-08-22
      Issue No: Vol. 68 (2017)
       
  • SYNTHESIS AND ANTIBACTERIAL PROPERTIES OF N,N-DISUBSTITUTED β-AMINO ACIDS
           CONTAINING FUNCTIONALIZED THIAZOLE FRAGMENT IN THE STRUCTURE

    • Authors: E. Urbonavičiūtė, R. Vaickelionienė, G. Vaickelionis, V. Mickevičius
      Abstract: Aminothiazoles were synthesized from the thioureido acid and halo carbonyl compounds by the Hantzsch method. The bromination of thiazolone, performed in acetic acid at 30 °C, gave the expected product 3-[(5,5-dibromo-4-oxo-4,5-dihydrothiazol-2-yl)(4-methoxyphenyl)amino]propanoic acid. The methylene group in the five-membered heterocyclic ring easily participates in condensation reactions with carbaldehydes. All these reactions were carried out in a mixture of water and 2-propanol in the presence of sodium carbonate. The formed sodium salts were converted into acids by acidifying the reaction mixture with acetic acid to pH 6. The 3-[{5-[4-{[2-[(2-carboxyethyl)-(4-methoxyphenyl)amino]-4-oxo-1,3-thiazol-5(4H)-ylidene]methyl}phenyl)methylidene]-4-oxo-4,5-dihydro-1,3-thiazol-2-yl]-(4-methoxyphenyl)-amino]propanoic acid was obtained analogously to the above-mentioned method, only instead of carbaldehyde using dialdehyde terephthalaldehyde. The synthesized compounds 1-13 were evaluated for their antibacterial activity against the Xanthomonas campestris, Rhizobium radiobacter and Escherichia coli strains by the agar diffusion technique. Their activities were compared with those of the known antibacterial agent ampicillin (control C). The evaluation was performed at the Laboratory of Biotechnology of the Department of Organic Chemistry (Kaunas University of Technology). The growth of bacteria and the antibacterial activity were determined by using the Luria-Bertani (LB) nutrition media. The following concentrations of solutions in dimethyl sulfoxide were prepared: 1000, 500, 250, 125, 50 and 25 μg/ml. The prepared test-samples were incubated at 37 °C for 48 h. The effectiveness of the compounds was determined by measuring the zones of inhibition on a bacterial culture. The test cultures of E. coli appeared not to be sensitive to any concentration of the tested compounds. Nine of the thirteen compounds were inactive against the Xanthomonas campestris bacterium strain, and only four of them – the condensed aminothiazole derivative 3-[(4-methoxyphenyl)-(4,5,6,7-tetrahydrobenzothiazol-2-yl)amino]propanoic acid (4) and thiazolone derivatives 3-[(5,5-dibromo-4-oxo-4,5-dihydrothiazol-2-yl)(4-methoxyphenyl)amino]propanoic acid (6), (Z)-3-[(5-(4-bromobenzylidene)-4-oxo-4,5-dihydrothiazol-2-yl)(4- methoxyphenyl)amino]propanoic acid (8), and (Z)-3-[(5-(4-chlorobenzylidene)-4-oxo-4,5-dihydro-thiazol-2-yl)(4- methoxyphenyl)amino]propanoic acid (9) at a concentration of 1000 μg/ml inhibited the growth of the X. campestris strain. It should be noted that compound 9 (at the same concentration) was also active against the Rh. radiobacter bacterium strain. Hence, the results revealed the most effective compound – (Z)-3-[(5-(4-chlorobenzylidene)-4-oxo-4,5-dihydrothiazol-2-yl)(4-methoxyphenyl)amino]propanoic acid (9), which inhibited the growth of the Xanthomonas campestris and Rhizobium radiobacter bacteria strains.
      DOI : http://dx.doi.org/10.5755/j01.ct.68.1.18877
      PubDate: 2017-08-22
      Issue No: Vol. 68 (2017)
       
  • BACTERIA OF THE GENUS BACILLUS AS A METHOD OF DIRECTED MODIFICATION OF
           POLYCAPROAMIDE FIBERS

    • Authors: Y. Komarovskaya, G. Yuhnevich, V. Burd, J. Mystkowska, W. Karalus, J. R. Dambrowski
      Abstract: In this paper, studies are presented that indicate the feasibility and effectiveness of the use of the genus Bacillus microorganisms for the directional modification of physicomechanical properties (strength, nominal stretching) of polycaproamide fibers and the production of high-strength polymer-matrix composites. Bacteria of the genus Bacillus can affect the structure of the surface of the fibers by increasing the nanoroughness and the amorphous layer. It is possible to use Bacillus brevis, Bacillus subtilis, Bacillus mesentericus and others strains to improve the consumer characteristics by the direct biodegradation of polycaproamide fibers.
      DOI : http://dx.doi.org/10.5755/j01.ct.68.1.18878
      PubDate: 2017-08-22
      Issue No: Vol. 68 (2017)
       
  • EFFECT OF VARIOUS CARBOHYDRATE ADDITIVES ON PEROXIDE FORMATION IN FAT FOR
           CONFECTIONERY PRODUCTION

    • Authors: V. Vītola, B. Ozola
      Abstract: A lot of ingredients used for food may have their own antioxidant activity. For this reason, it is necessary to explore the effect of natural antioxidants and non-specific antioxidants of some confectionery ingredients for the stabilization of food products against the formation of peroxides. The aim of the study was to verify the effect of some carbohydrates in preventing the formation of peroxides in fat for the confectionery production and to prove that the quality and shelf-life of confectionery products are affected by ingredients used in the compositions of confectionery products and by compounds that are formed in their interaction. Butter was used as the basic ingredient to study the fat stability. The effect of carbohydrates used in confectionery and their interaction with butter was examined, and the peroxides were determined. The effect of vanillin in facilitating or preventing the above-mentioned interaction was also determined. Peroxides were determined by means of the standard LVS EN ISO 3960:2010. It was established that practically all carbohydrates decreased the formation of peroxides in the samples. The quantity of peroxides in butter with 30 % of sucrose was by 10.7 % lower, with 30 % of glucose – by 41.3 % lower comparing to butter without additives after the samples had been stored for 30 days at 28 ± 2 °C. The most effective after 30 days of storage was sorbitol which decreased the formation of peroxides by 65.3 %. The same activity was also established for vanillin. Its antioxidant activity was similar to the activity of sugars, and therefore their summary activity reduces in confectionery products. It is established that the activity of sugars is quite temporary, and with increasing the quantity of peroxides in the product it decreases or completely disappears.
      DOI : http://dx.doi.org/10.5755/j01.ct.68.1.18879
      PubDate: 2017-08-22
      Issue No: Vol. 68 (2017)
       
 
 
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