DOCSLIB.ORG

Dye Manufacturing

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Dye Manufacturing Multilateral Investment Guarantee Agency Environmental Guidelines for Dye Manufacturing Industry Description and Practices dyes by use classification comprises the following: This document addresses the synthesis of dyes • Acetate rayon dyes: developed for cellulose acetate and pigments used in textiles and other and some synthetic fibers; industries. Dyes are soluble at some stage of the • Acid dyes: used for coloring animal fibers via application process, whereas pigments in acidified solution (containing sulfuric acid, acetic acid, general retain essentially their particulate or sodium sulfate, and surfactants) in combination with crystalline form during application. A dye is amphoteric protein. used to impart color to materials of which it • Azoic dyes: contain azo group (and formic acid, becomes an integral part. Aromatic ring caustic soda, metallic compounds, and sodium nitrate) structure coupled with a side chain is usually especially for applying on cotton . required for resonance and in turn impart color. • Basic dyes: amino derivatives (and acetic acid and Resonance structures which cause displacement softening agents) used mainly for application on paper. or appearance of absorption bands in the visible • Direct dyes: azo dyes (and sodium salts, fixing spectrum of light are responsible for color. agents, and metallic [chrome and copper] compounds) used Correlation of chemical structure with color has generally on cotton-wool or cotton-silk combinations. been accomplished in the synthesis of dye using • Mordant or chrome dyes: metallic salt or lake formed a chromogen-chromophore with auxochrome. directly on the fiber by the use of aluminum, chromium, or Chromogen is the aromatic structure containing iron salts which cause precipitation in situ. benzene, naphthalene, or anthracene rings. A • Lake or pigment dyes: form insoluble compounds chromophore group is a color giver and is with aluminum, barium, chromium, on molybdenum [Mo] represented by the following radicals which salts, the precipitates are ground to form pigments used in form a basis for chemical classification of dyes paint and inks. when coupled with the chromogen: (a) azo (- • Sulfur or sulfide dyes: contain sulfur or precipitated N=N-); (b) carbonyl (=C=O); (c) carbon from sodium sulfide bath; furnish dull shades with good (=C=C=); (d) carbon-nitrogen (>C=NH or - fastness to light, washing, and acids, but susceptible to CH=N-); (e) nitroso (-NO or N-OH); (f) nitro chlorine and light. (-NO2 or =NO-OH); (g) and sulfur (>C=S, and • Vat dyes: impregnated into fiber under reducing other carbon-sulfur groups). The conditions which reoxidizes to an insoluble color. chromogen:chromophore structure is often not Chemical classification is based on sufficient to impart solubility and to cause chromogen. For example, nitro dyes have the adherence of dye to fiber. The auxochrome or chromophore - NO2 under which Naphthol bonding affinity groups are amine; hydroxyl; Yellow S, C.I. 10 is classified. The coding S carboxyl; and sulfonic radicals or their comes from commercial designation and relates derivatives. These auxochromes are important to color or application (B - for bluish; G - for in the use classification of dyes. A listing of greenish or yellowish [gelbich in German]; R - reddish; S - sulfur containing or dye for silk; W - 363 364 Dye Manufacturing wool dye; L - lake forming, easily soluble of COD, 6 kg of suspended solids, and 30 g of [loslich in German ], or for linen). The Color oil and grease per kg of product. Index (C.I.) published by the Society of Dyers Major solid wastes of concern include and Colourists (UK), in cooperation with the filtration sludges, process and effluent American Association of Textile Chemists and treatment sludges, and container residues. Colorists (AATC), provides a detailed Examples of wastes considered toxic include classification of commercial dyes and pigments wastewater treatment sludges, spent acids, and by generic name and chemical constitution. This process residues from the manufacture of sourcebook also provides useful information on chrome yellow and orange pigments, technical performance, physical properties, and molybdate orange pigments, zinc yellow application areas. pigments, chrome and chrome oxide green Dyes are synthesized in a reactor, filtered, pigments, iron blue pigments, and azo dyes. dried, and blended with other additives to produce the final product. The synthesis step Pollution Prevention and Control involves reactions such as sulfonation, halogenation, amination, diazotization, and Every effort should be made to substitute highly coupling followed by separation processes toxic and persistent ingredients with degradable which may include distillation, precipitation, and less toxic ones. Recommended pollution and crystallization. In general, organic prevention measures are: compounds such as naphthalene are reacted • Avoid the manufacture of toxic azo dyes and provide with an acid or an alkali along with an alternative dyestuff to users such as textile manufacturers. intermediate (such as a nitrating or a • Meter and control the quantities of toxic ingredients sulfonating compound) and a solvent to form a to minimize wastage. dye mixture. The dye is then separated from the • Reuse by-products from the process as raw materials mixture and purified. On completion of the or as raw material substitutes in other processes. manufacture of actual color, finishing • Use automated filling to minimize spillage. operations including drying, grinding, and • Use equipment washdown waters as make-up standardization are performed and these are solutions for subsequent batches. important for maintaining consistent product • Return toxic materials packaging to supplier for quality. reuse, where feasible. • Find productive uses for off-specification products to Waste Characteristics avoid disposal problems. • Use high pressure hoses for equipment cleaning to The principal air pollutants are volatile organic reduce wastewater generated. compounds (VOCs), nitrogen oxides (NOx), • Label and store toxic and hazardous materials in hydrogen chloride (HCl), and sulfur oxides secure bunded areas. (SOx). A dye and pigment manufacturing plant Liquid effluents resulting from equipment should prepare and implement an Emergency cleaning after batch operation, can contain toxic Plan which takes into account neighboring land organic residues. Cooling waters are normally uses and the potential consequences of an recirculated. Wastewater generation rates are of emergency. Measures to avoid the release of the order of 1-700 liters per kg (L/kg) of harmful substances should be incorporated in product except for vat dyes. The wastewater the design operation, maintenance, and generation rate for vat dyes can be of the order management of the plant. of 8,000 (L/kg) of product. The biochemical oxygen demand (BOD5) and chemical oxygen Target Pollution Loads demand (COD) levels of reactive and azo dyes can be of the order of 25 kg and 80 kg per kg of Implementation of cleaner production processes product respectively. Values for other dyes are, and pollution prevention measures can provide for example, 6 kg of BOD5 together with 25 kg both economic and environmental benefits. 365 Dye Manufacturing Specific reduction targets for the different The following guidelines present emission processes have not been determined. In the levels normally acceptable to the World Bank absence of specific pollution reduction targets, Group in making decisions regarding provision new plants should always achieve better than of World Bank Group assistance, including the industry averages quoted in the section on MIGA guarantees; any deviations from these Waste Characteristics. levels must be described in the project documentation. Treatment Technologies The guidelines are expressed as concentrations to facilitate monitoring. Dilution Air Emissions of air emissions or effluents to achieve these guidelines is unacceptable. Stack gas scrubbing and/or carbon adsorption All of the maximum levels should be (for toxic organics) are applicable and effective achieved for at least 95% of the time that the technologies for minimizing the release of plant or unit is operating, to be calculated as a significant pollutants to air. Combustion is used proportion of annual operating hours. for the destruction of toxic organics. Combustion devices should be operated at Air Emissions temperatures above 1,1000C (when required for the effective destruction of toxic organics) with The following emissions levels should be a residence time of at least 0.5 second. achieved: Liquid Effluents Emissions from Dye Manufacturing Parameter Maximum value Effluent treatment normally includes (milligrams per neutralization, flocculation, coagulation, normal cubic meter settling, carbon adsorption, detoxification of (mg/Nm3)) organics by oxidation (using ultraviolet systems or peroxide solutions), and biological treatment. Chlorine (or chloride) 10 Exhausted carbon from absorption processes VOCs 20 may be sent for regeneration or combustion. Reverse osmosis, ultra-filtration and other Liquid Effluents filtration techniques are used to recover and concentrate process intermediates. The following effluent levels should be achieved: Solid Hazardous Wastes Effluents from Dye Manufacturing Contaminated solid wastes are generally Parameter Maximum value incinerated and the flue gases, when acidic, are milligrams per scrubbed. liter (mg/L) Emission Guidelines PH 6-9 BOD5 30 Emission levels for
Load more

Recommended publications
  • UG 4Th Sem Organic SN-UV Vis 2.Pdf
    Introduction The molecular spectroscopy is the study of the interaction of electromagnetic waves and matter. The scattering of sun’s rays by raindrops to produce a rainbow and appearance of a colorful spectrum when a narrow beam of sunlight is passed through a triangular glass prism are the simple examples where white light is separated into the visible spectrum of primary colors. This visible light is merely a part of the whole spectrum of electromagnetic radiation, extending from the radio waves to cosmic rays. All these apparently different forms of electromagnetic radiations travel at the same velocity but characteristically differ from each other in terms of frequencies and wavelength (Table 1). Table 1: The electromagnetic spectrum Radiation type Wave length Frequency Applications λ , (Ǻ) ν = c / λ, (Hz) radio 1014 3 x 104 Nuclear magnetic resonance 1012 3 x 106 Television 1010 3 x 108 Spin orientation Radar 108 3 x 1010 Microwave 107 3 x 1011 Rotational Far infrared 106 3 x 1012 Vibrational Near infrared 104 3 x 1014 Visible 8 x 103 - 4 x 103 3.7 x 1014 - 7.5 x 1014 Ultraviolet 3 x 103 1 x 1015 Electronic X-rays 1 3 x 1018 Gamma rays 10-2 3 x 1020 Nuclear transitions Cosmic rays 10-4 3 x 1022 The propagation of these radiations involves both electric and magnetic forces which give rise to their common class name electromagnetic radiation. In spectroscopy, only the effects associated with electric component of electromagnetic wave are important. Therefore, the light wave traveling through space is represented by a sinusoidal trace (figure 1).
    [Show full text]
  • Influence of Auxochrome Group in Disperse Dyes Bearing Azo Groups
    Ecotoxicology and Environmental Safety 160 (2018) 114–126 Contents lists available at ScienceDirect Ecotoxicology and Environmental Safety journal homepage: www.elsevier.com/locate/ecoenv Influence of auxochrome group in disperse dyes bearing azo groups as T chromophore center in the biotransformation and molecular docking prediction by reductase enzyme: Implications and assessment for environmental toxicity of xenobiotics Jefferson Honorio Francoa, Bianca F. da Silvaa, Elisangela Franciscon G. Diasb, ⁎ Alexandre A. de Castroc, Teodorico C. Ramalhoc, Maria Valnice Boldrin Zanonia, a Institute of Chemistry, State University “Julio de Mesquita Filho”- UNESP, Araraquara, São Paulo, Brazil b School of Technology, University of Campinas - UNICAMP, Limeira, São Paulo, Brazil c Department of Chemistry, Federal University of Lavras - UFLA, Lavras, Minas Gerais, Brazil ARTICLE INFO ABSTRACT Keywords: Synthetic azo dyes have increasingly become a matter of great concern as a result of the genotoxic and muta- Textile dye genic potential of the products derived from azo dye biotransformation. This work evaluates the manner in Biotransformation which reducing enzymes produced by Escherichia coli (E. coli) act on three disperse dyes bearing azo groups, Azoreductase namely Disperse Red 73 (DR 73), Disperse Red 78 (DR 78), and Disperse Red 167 (DR 167). UV–Vis spectro- Mass spectrometry photometry, high-performance liquid chromatography with diode array detector (HPLC-DAD), and liquid Escherichia coli chromatography mass spectrometry (LC-MS/MS) were applied towards the identification of the main products. Seven days of incubation of the azo dyes with the tested enzymes yielded a completely bleached solution. 3–4- Aminophenyl-ethyl-amino-propanitrile was detected following the biotransformation of both DR 73 and DR 78.
    [Show full text]
  • Spectroscopic Studies of Carbocyanine and 2,4,6- Trisubstituted Pyridine Dyes for Bioanalytical and Ph Indicating Applications
    Georgia State University ScholarWorks @ Georgia State University Chemistry Theses Department of Chemistry Fall 11-29-2011 Spectroscopic Studies of Carbocyanine and 2,4,6- Trisubstituted Pyridine Dyes for Bioanalytical and pH Indicating Applications Gala M. Chapman Georgia State University, [email protected] Follow this and additional works at: https://scholarworks.gsu.edu/chemistry_theses Recommended Citation Chapman, Gala M., "Spectroscopic Studies of Carbocyanine and 2,4,6- Trisubstituted Pyridine Dyes for Bioanalytical and pH Indicating Applications." Thesis, Georgia State University, 2011. https://scholarworks.gsu.edu/chemistry_theses/47 This Thesis is brought to you for free and open access by the Department of Chemistry at ScholarWorks @ Georgia State University. It has been accepted for inclusion in Chemistry Theses by an authorized administrator of ScholarWorks @ Georgia State University. For more information, please contact [email protected]. SPECTROSCOPIC STUDIES OF CARBOCYANINE AND 2,4,6-TRISUBSTITUTED PYRIDINE DYES FOR BIOANALYTICAL AND pH INDICATING APPLICATIONS by GALA CHAPMAN Under the Direction of Dr. Gabor Patonay ABSTRACT In part A, the effect of varying short-chain alkyl substitution on the spectroscopic properties of cyanine dyes was examined. Molar absorptivities and quantum yields were determined for groups of pentamethine and heptamethine dyes for which the substitution of the indole nitrogen was varied. For both sets of dyes, increasing alkyl chain length did not significantly change quantum yield or molar absorptivity. These results may be useful in designing new cyanine dyes. In part B, the effect of structure on the suitability of 2,4,6-trisubstituted pyridines as color pH indicators was studied by determining spectral effects of protonation, molar absorptivities, pKa values, and the structural origin of the spectral behavior.
    [Show full text]
  • B.Sc. Semester 6 (Paper -14, Organic Chemistry) SET-1
    B.Sc. Semester 6 (Paper -14, Organic Chemistry) SET-1 Full marks=60 I. Objective Question: (1x15=15) 1. Wave number is given by the formula (a) λ (b) 1/λ (c) λ 2 (d)1/ λ2 2. Hooke’s law for the vibration of a diatomic molecule may be represented as (a) F= kx (b) F= -kx (c) x= kF (d) ) x= -kF 3. Bathochromic effect is also called (a) Blue Shift (b) Red Shift (c) Green Shift (d) None of these 4. Broad, moderately intense absorbtion in the low frequency region suggests the presence of (a) Carboxylic acid (b) Amides (c) Amines (d)All of these 5. How many NMR signals would be given by (CH3)2CHCH2CH3 (a) 3 (b) 4 (c) 5 (d) 2 6. If a proton is linked to some electronegative atom via hydrogen bond, absorption in NMR will be (a) upfield (b) unchanged (c) downfield (d) None of theses 7. The number of asymmetric carbon atoms in a α–D-glucopyranose is (a) 3 (b) 4 (c) 5 (d) 2 8. The sugar that yields only glucose on hydrolysis (a) Lactose (b) Sucrose (c) Maltose (d) Fructose 9. All of the following monosaccharides give the same osazone except (a) Galactose (b) Glucose (c) Mannose (d) Fructose 10. Monomer of Neoprene is (a) Chloroprene (b) Isoprene (c) Isobutane (d) Isopentene 11. Adipic acid reacts with hexamethylene diamine to form (a) bakelite (b) Nylon-6,6 (c) Polyethylene (d) Teflon 12. Orlon is prepared by polymerization of (a) vinyl cynide (b) allyl alcohol (c) vinyl chloride (d) allyl chlride 13.
    [Show full text]
  • Chapter 1--Title
    Chapter 6 Part III UV-Vis Spectroscopy THE ELECTROMAGNETIC RANGE 10-10–10-8 nm 10 nm – 400 nm 2 Chapter 6 THE NATURE OF ELECTRONIC EXCITATIONS When continuous radiation passes through a transparent material, a portion of the radiation may be absorbed. As a result of energy absorption, atoms or molecules pass from a state of low energy (the initial, or ground state) to a state of higher energy (the excited state). The electromagnetic radiation that is absorbed has energy exactly equal to the energy difference between the excited and ground states. 3 Chapter 6 Types of spectroscopy Electromagnetic Type of Transition Used to range spectroscopy between determine Infrared IR spectroscopy Vibrational Functional (2,5 – 15 μm) energy levels groups (400 - 4000 cm-1) Radio-wave NMR Nuclear spin Carbon– (1 m – 5 m) spectroscopy states hydrogen framework Ultraviolet UV-Vis Electronic Nature and (~ 200 – 400 nm) spectroscopy energy levels extent of – Visible conjugated π (~400-800 nm) electron system Mass spectroscopy - Molecular size and formula Chapter 6 4 The UV-Vis region The ultraviolet (UV) and visible (Vis) regions are the portions of the electro-magnetic spectrum where wavelengths range from 200 nm to 800 nm. 5 Chapter 6 In the case of ultraviolet and visible spectroscopy, the transitions that result in the absorption of electromagnetic radiation in this region of the spectrum are transitions between electronic energy levels. As a molecule absorbs energy, an electron is promoted from an occupied orbital to an unoccupied orbital of greater potential energy. Generally, the most probable transition is from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO).
    [Show full text]
  • Dual Degree B.Sc. (Hons.) Physics-M.Sc. Physics
    SCHEME AND SYLLABI FOR Dual Degree B.Sc. (Hons.) Physics-M.Sc. Physics (3+2 YEARS PROGRAMME) (Under Choice Based Credit System) 1st to 6th semester from academic session 2019-20 & 7th to 10th semester (Revised) from 2016-17 batch onward (70:30) DEPARTMENT OF PHYSICS GURU JAMBHESHWAR UNIVERSITY OF SCIENCE & TECHNOLOGY HISAR-125001, HARYANA Vision and Mission of the Department of Physics Vision: To inspire the young students towards understanding and learning the fundamental concepts of Physics and their applications for the development of new technologies in the national interests. Mission: Physics is regarded as the most significant subject among all scientific and technical disciplines. The mission of Physics department at Guru Jambheshwar University of Science & Technology is to provide both the undergraduate and postgraduate students strong qualitative and quantitative knowledge along with developing a problem solving attitude that may open up a wide range of career choices. In addition, the mission also includes encouraging the research scholars to conduct cutting-edge research resulting in new discoveries and innovations that expands the horizons of science and technology. This mission will be accomplished by providing students with rigorous and comprehensive knowledge as well as bringing exciting research perspectives to the student community of Physics Department at Guru Jambheshwar University of Science & Technology. Dual Degree B.Sc. (Hons.) Physics-M.Sc. Physics (3+2 years) programme: B.Sc. (Hons.)-M.Sc. dual degree programme in Physics has been started in the year 2016 to attract young bright students to inculcate the culture of research and development in the areas of physical sciences.
    [Show full text]
  • Synthesis of Dyes
    Ursinus College Digital Commons @ Ursinus College Chemistry Honors Papers Student Research 9-1944 Synthesis of Dyes Faith B. Cramer Follow this and additional works at: https://digitalcommons.ursinus.edu/chem_hon Part of the Chemistry Commons Click here to let us know how access to this document benefits ou.y Ursinus College Library, URCINUSIAMA COLLECTION Class 0 Boxg/Wr^ Synthesis of Dyes Faith B. Cramer, C6<J.^(i^/^f^5^ Department Honors Ursinus College September, 1944 This paper is submitted in partial fulfillment of Department Honors. Group Adviser Introduotion The dyeing property is dependent wgon structure; The charact• er 'of the lyestuff is derived from some group contained in it, called the chromophore.The most important chromophores are C:C, C:0,C:S,C:N,N:N,N:0,ji:0,..Chromophores vary in their effective• ness to produce color.In general,color deepens as the molecular weight increases,especially as the number of chromophores in• creases . The fundamental substance containing the chromophore is the chrom.ogen. The chromogen is not a dyestuff,but is converted into this by the entrance of some salt-forming group which de• stroys the chemically inert character of the chromogen. The groups conferring salt-forming properties upon the chromogen are auxochromes,which fall into two groups: a)acidic:SO,H, COOH, OH B] b)basic:KH,,, NHR, NRo. Often ajbolorless chromogen becomes colored upon introduction of an auxochrome.Benzophenono,for example,becomes yellow when -NHi group is introduced.Azobenzene,which is red,becomes a dye when -NHj^ is intiDoduced in the para position,Certain auxochromes have a higher effectiveness than others.
    [Show full text]
  • • M.Sc. (2Yr & 5Yr) • M.A. • M.B.A. CURRICULA and SYLLABI
    CURRICULA AND SYLLABI • M.Sc. (2yr & 5yr) • M.A. • M.B.A. www.nitrkl.ac.in PREAMBLE The curriculum of an institution of higher learning is a living entity. It evolves with time; it reflects the ever changing needs of the society and keeps pace with the growing talent of the students and the faculty. The curriculum of the MSc, MA and MBA programmes of NIT Rourkela is no exception. Half a century of experience in preparing graduates in engineering and postgraduates in science for a wide variety of industries has led to creation of the new curriculum. I sincerely believe that it will meet the aspirations of all stake holders – students, faculty and the employers of the graduates and postgraduates of NIT Rourkela. In the old college – university system the curricula and syllabi represented the upper limit of the material to be covered, the teacher having no motivation for stepping outside the defined territory. In the autonomous institute system, the curriculum and syllabi only serve as a guideline. The teacher enjoys freedom to expand it in any direction he feels appropriate, incorporates his latest knowledge and stimulates the creative minds of the students. He experiments with new contents and new techniques. A new teaching-learning paradigm is born. This book of curricula is the culmination of the efforts of large number of faculty members and supporting staff. It also reflects the creative contribution of hundreds of teachers – both serving and retired, over the past five decades. In keeping with the demands of the changing times, it contains many innovative features.
    [Show full text]
  • Instrumental Analysis
    Instrumental Analysis Part (1) Fundamentals of Spectrophotometry UV-VIS-IR Luminescence Atomic Spectroscopy Dr. Jamal Al Abdullah @JamalAlabdullah Fundamentals of Spectrophotometry Reminder Properties of Light Absorption of Light The Spectrophotometer Beer’s Law in Chemical Analysis What happens when a molecule absorbs light? Luminescence Analytical Chemistry Identification, Determination of Ingredient substances, Stability study, Bioequivalence study, Bioavailability study, Base of most supplemented sciences of pharmacy, Research and development of pharmacy, Drug industry, Drug delivery, (A new science branch, Pharmacy, Chemistry, Biology, etc.), Analytical Chemistry Qualitative analysis Quantitative analysis Aspirin Form (Stability) Solubility Reminder • Prefixes of SI units pico nano micro milli centi kilo mega p n m m c k M 10-12 10-9 10-6 10-3 10-2 103 106 • Example: 109 m 1m or nm 109 nm Reminder Reminder Concentration units 1. Mass Percent, 2. Volume Percent, 3. Mole Fraction, 4. Molarity, 5. Molality, 6. Normality, 7. Parts per Million, Parts per Billion, Parts per Trillion. Reminder: Calibration Methods Instrument calibration • A new instrument, • After reparation. • After a specified time period, Operating hours, • After/before a critical measurement, • After an event, i.e., shock, accident, questionable observations, instrument manufacturer recommendation. Calibration Curve: Conc.---Response External Standard The Standard Addition Method . Sample treatment: Recovery . Matrix effect: Calibration correction .
    [Show full text]
  • Colours and Chromophores
    © Department of Chemistry, The University of Western Ontario Chem 2223b Intersession 2008: Colours and Chromophores • This section discusses the absorption of light by organic compounds, the related photophysical processes, and the spectroscopic methods used to measure light absorption and emission. Examples of important chromophores will be introduced. • Background material, from Chem 2213a or otherwise, that is important includes: o Primary colours and the colours of the rainbow o Relationship between wavelength and energy o Bonding and hybridization o Conjugation and resonance structures • After completing this section and Experiment 1, attempt: o Practice problems in the lab manual: all except for question #10 o 2006 Midterm: 17, 18, 29, 30. 2006 Midterm Intersession: 22, 23, 26, 40. o 2007 Term Test #2: 7 to 11. 2008 Midterm: 1 to 5. Chromophores 2 A. Colour • White light is a continuum of different colours. If white light, such as sunlight, is passed through clouds or a prism, then it can be split up into its constituent colours, each of which has a different wavelength. • When white light strikes an object or a substance, a specific colour component may be absorbed. The remaining colour components, which are not absorbed, are reflected or transmitted, and are what our eyes detect. We perceive this as the complementary colour of what is absorbed. • This assumes that the absorbed component is a colour that our eyes can see. For example, the absorption of UV by an object would not be observable. higher energy lower energy lower λ (nm) higher λ (nm) VB GY O R Colour absorbed UV IR Complementary (what we see) YO R V BG Chromophores 3 • Using this complementary-colour system, we can approximate the colour of light absorbed by some everyday objects and substances.
    [Show full text]
  • CH 2020/2290 Materials
    CH 2020/2290 Dyes and Dyeing (adapted from Organic Chemistry: A Short Course, H. Hart, L. E. Craine, D. J. Hart, and T.K. Vinod 13th ed. Houghton-Mifflin, Boston, 2012.) Materials From the Chemicals Hood: From the Side Shelf: Malachite green Sodium carbonate (3) 13-fiber Test Fabric strips Congo red Tannic acid Introduction Why are dyes colored? Dyes contain chromophores (“color bearers”), which are unsaturated functional groups, such as those in Figure 1, that absorb certain wavelengths of electromagnetic energy, usually in the ultraviolet region. When a chromophore is attached to a system of pi conjugated electrons, the wavelength that the chromophore absorbs increases with increasing size of the conjugated system. This can bring the wavelength absorbed by the chromophore into the visible region. What color the dye appears is the complementary color of the color which is being absorbed by the chromophore; for example, if a chromophore absorbs green light (500 nm), the observer will see a red color from the dye. Figure 1. Examples of chromophores Auxochromes (“color helpers”), such as those in Figure 2, contain a lone pair of electrons which can be donated into a conjugated system. The delocalization of electrons imparted by the resulting resonance, shown in Figure 3, has the effect of lengthening the conjugated system, and increases the wavelength at which the chromophore absorbs. Figure 2. Typical auxochromes Often dyes are affixed to the substance being dyed through anchoring groups, which are functional groups which can bind to the substance through ionic, covalent, or hydrogen bonding. Carboxylic acids (-COOH) or sulfonic acids (-SO3H) are common anchoring groups.
    [Show full text]
  • Faculty of Materials Science and Technology in Trnava Slovak University of Technology in Bratislava
    RESEARCH PAPERS FACULTY OF MATERIALS SCIENCE AND TECHNOLOGY IN TRNAVA SLOVAK UNIVERSITY OF TECHNOLOGY IN BRATISLAVA 10.1515/rput-2017-0012 2017, Volume 25, Number 40 USAGE OF FTIR-ATR AS NON-DESTRUCTIVE ANALYSIS OF SELECTED TOXIC DYES Alica BARTOŠOVÁ, Lenka BLINOVÁ, Maroš SIROTIAK, Anna MICHALÍKOVÁ SLOVAK UNIVERSITY OF TECHNOLOGY IN BRATISLAVA, FACULTY OF MATERIALS SCIENCE AND TECHNOLOGY IN TRNAVA, INSTITUTE OF INTEGRATED SAFETY, ULICA JÁNA BOTTU 2781/25, 917 24 TRNAVA, SLOVAK REPUBLIC e-mail: alica.bartosova @stuba.sk, [email protected], [email protected], [email protected] Abstract The degradation of the environment which is due to the discharge of polluting wastewater from industrial sources poses a real problem in several countries. Textile industries use large volumes of water in their operations, discharging thus large volume of wastewater into the environment, most of which is untreated. The wastewater contains a variety of chemicals from various stages of process operations, including desizing, scouring, bleaching and dyeing. The main purpose of this paper is to introduce Infrared Spectrometry with Fourier transformation as a non-destructive method for study, identifation and rapid determination of selected representatives of cationic (Methylene Blue), azo (Congo Red, Eriochrome Black T) and nitroso (Naphthol Green B) dyes. In conjunction with the ATR technique, FTIR offers a reliable detection method of dyes without extraction by other dangerous substances. Spectral interpretation of dye spectra revealed valuable information about the identification and characterization of each group of dyes. Key words FTIR-ATR, azo dye, nitroso dye, basic dye, spectrum INTRODUCTION During the last century, a huge amount of industrial wastewater, especially from developing countries, was discharged into rivers, lakes and coastal areas.
    [Show full text]