Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Their Use

All the indicators discussed above are based on mass intensity. These indicators have been developed specifically for their use in synthetic chemistry, either at the laboratory or industry level. They have in common the objective of showing to what extent a chemical reaction is wasteful in material terms simplicity is their main merit, as most of them can be easily calculated as soon as the chemical reaction is defined and quantified. [Pg.298]

However, they include neither information on energy issues nor on the toxicity or hazards associated with the inputs used and the waste produced. Another question is which indicator to use. Sometimes, different indicators can lead to different (conflicting) results, as shown by Constable et al. [39], who checked 28 chemical reactions against yield, atom economy, carbon efficiency, RMI, MI and mass productivity. [Pg.298]


These relations should not be used if K, < 10 and A < 0. Their use is recommended for within the following range ... [Pg.95]

These compounds have been incorporated in the gasolines of the entire world since 1922. Their use will disappear with the general acceptance of catalytic converters with which they are totally incompatible. [Pg.206]

Petroleum solvents are relatively light petroleum cuts, in the C4 to C14 range, and have numerous applications in industry and agriculture. Their use is often related to their tendency to evaporate consequently, they are classified as a function of their boiling points. [Pg.271]

They are classified apart in this text because their use differs from that of petroleum solvents they are used as raw materials for petrochemicals, particularly as feeds to steam crackers. Naphthas are thus industrial intermediates and not consumer products. Consequently, naphthas are not subject to governmental specifications, but only to commercial specifications that are re-negotiated for each contract. Nevertheless, naphthas are in a relatively homogeneous class and represent a large enough tonnage so that the best known properties to be highlighted here. [Pg.275]

Automated data interpretation will usually be done using some statistical or AI technique. Because statistical classifiers are similar in their use to neural networks [Sarle, 1994] we will not discuss them separately. [Pg.98]

Sensitive parameters are necessary to compare several high resolution magnetic field sensors. Such parameters can be found with methods of signal theory for LTI-systems. The following chapter explains characteristic functions and operations of the signal analysis for linear local invariant systems and their use in non-destructive testing. [Pg.365]

During many years in Scientific Research Institutes of Nuclear Physics and Introscopy at Tomsk Polytechnical University (TPU) researches into induction electron accelerators and their uses for non-destructive radiation quality control of materials and articles have been conducted. Control sensitivity and efficiency detection experimental researches have been conducted with the high-current stereo-betatron modifications [1], and KBC-25 M and BC-50 high-current betatrons [2,3] in range of 11 MeV and 25-50 MeV radiation energy. [Pg.513]

Cracks depth measurement in billets for determining their use possibility for further machining. [Pg.652]

The preliminary observations underline the manufacturer s responsibilities. He is obliged to analyse the hazards in order to identify those which apply to his equipment. He must design, manufacture and check his equipment to ensure its safety even with respect to their use under reasonably foreseeable conditions. In addition, the manufacturer must interpret and apply the essential requirements in such a way as to take account of the state-of-the-art at the time of design. That latter requirement underlines the evolutive character of the essential requirements which is inherent in the new approach. [Pg.941]

Several convenient ways to measure surface tension involve the detachment of a solid from the liquid surface. These include the measurement of the weight in a drop falling from a capillary and the force to detach a ring, wire, or thin plate from the surface of a liquid. In this section we briefly describe these methods and their use. [Pg.19]

A few of the most frequently used techniques are discussed briefly in this chapter references to those not covered are given in the table. Useful reviews are Refs. 2-5 and 6 and, for organic surfaces. Refs. 7-9 and 10. Also, many of the various measurements have found use in the study of the adsorbed state, and further examples of their use are to be found in Chapters VII, XVI, and XVII. [Pg.293]

SAMs are generating attention for numerous potential uses ranging from chromatography [SO] to substrates for liquid crystal alignment [SI]. Most attention has been focused on future application as nonlinear optical devices [49] however, their use to control electron transfer at electrochemical surfaces has already been realized [S2], In addition, they provide ideal model surfaces for studies of protein adsorption [S3]. [Pg.397]

Kutzelnigg W and Maeder F 1978 Natural states of interacting systems and their use for the calculation of intermolecular forces. III. One-term approximations of oscillator strength sums and dynamic polarizabilities Chem. Phys. 35 397... [Pg.212]

A good introduction to the use of coherent optical teclmiques and their use to probe molecular spectra. Shen Y R 1984 The Principles of Non-linear Optics (New York Wiley)... [Pg.282]

A beautiful, easy-to-read introduction to wavepackets and their use in interpreting molecular absorption and resonance Raman spectra. [Pg.282]

From the above descriptions, it becomes apparent that one can include a wide variety of teclmiques under the label diffraction methods . Table Bl.21.1 lists many techniques used for surface stmctural detemiination, and specifies which can be considered diffraction methods due to their use of wave interference (table Bl.21.1 also explains many teclmique acronyms commonly used in surface science). The diffraction methods range from the classic case of XRD and the analogous case of FEED to much more subtle cases like XAFS (listed as both SEXAFS (surface extended XAFS) and NEXAFS (near-edge XAFS) in the table). [Pg.1753]

Optical metiiods, in both bulb and beam expermrents, have been employed to detemiine tlie relative populations of individual internal quantum states of products of chemical reactions. Most connnonly, such methods employ a transition to an excited electronic, rather than vibrational, level of tlie molecule. Molecular electronic transitions occur in the visible and ultraviolet, and detection of emission in these spectral regions can be accomplished much more sensitively than in the infrared, where vibrational transitions occur. In addition to their use in the study of collisional reaction dynamics, laser spectroscopic methods have been widely applied for the measurement of temperature and species concentrations in many different kinds of reaction media, including combustion media [31] and atmospheric chemistry [32]. [Pg.2071]

The generally low chemical, mechanical and thennal stability of LB films hinders their use in a wide range of applications. Two approaches have been studied to solve this problem. One is to spread a polymerizable monomer on the subphase and to polymerize it either before or following transfer to the substrate. The second is to employ prefonned polymers containing hydrophilic and hydrophobic groups. [Pg.2618]

If the normal carbonate is used, the basic carbonate or white lead, Pb(OH),. 2PbCO,. is precipitated. The basic carbonate was used extensively as a base in paints but is now less common, having been largely replaced by either titanium dioxide or zinc oxide. Paints made with white lead are not only poisonous but blacken in urban atmospheres due to the formation of lead sulphide and it is hardly surprising that their use is declining. [Pg.202]

The reducing action of sulphurous acid and sulphites in solution leads to their use as mild bleaching agents (for example magenta and some natural dyes, such as indigo, and the yellow dye in wool and straw are bleached). They are also used as a preservative for fruit and other foodstuffs for this reason. Other uses are to remove chlorine from fabrics after bleaching and in photography. [Pg.292]

The ability of the solid chlorates(V) to provide oxygen led to their use in matches and fireworks. Bromates(V) and iodates(V) are used in quantitative volumetric analysis. Potassium hydrogen diiodate(V), KHflOjlj, is used to standardise solutions of sodium thiosulphate(Vf) since in the presence of excess potassium iodide and acid, the reaction... [Pg.340]

Trivial or trade namc.s can be stored and searched as character strings. Their use is the simplest and most intuitive way of storing chemical information. However, being not subject to strict rules, their formation does not reflect accurately the molecular composition. Hence, the structure of the searched compound cannot be derived from them. Thus, a name such as "Flexricin does not tell the user very much. Furthermore, many more than one trivial or trade name for a given compound usually exist. [Pg.293]

Th c syn tax and scmari tics of ih e typiri g rules in a cti ern, ni I file arc Inchuied m the HyperChcm Reference Manual. The following example illustrates their use. The five. A.MHKR types for oxygen atoms sh own above are defin ed in cheni. rtil by th e followin g rules ... [Pg.171]

Judson R 1997, Genetic Algorithms and Their Use in Chemistry. In Lipkowitz K B and D B Boyd (Editors) Reviews in Computational Chemistry Volume 10. New York, VCH Publishers, pp. 1-73. [Pg.523]

Sodium and potassium hydroxides. The use of these efficient reagents is generally confined to the drying of amines (soda lime, barium oxide and quicklime may also be employed) potassium hydroxide is somewhat superior to the sodium compound. Much of the water may be first removed by shaking with a concentrated solution of the alkali hydroxide. They react with many organic compounds (e.g., acids, phenols, esters and amides) in the presence of water, and are also soluble in certain organic liquids so that their use as desiccants is very limited... [Pg.142]

This is the basis of their use as ion exchange resins. The resin can be regenerated by treatment with dilute acids. Further developments have... [Pg.1019]

Are cost effective in that their use in practical calculations is feasible. [Pg.467]

Lead oxide is used in producing fine "crystal glass" and "flint glass" of a high index of refraction for achromatic lenses. The nitrate and the acetate are soluble salts. Lead salts such as lead arsenate have been used as insecticides, but their use in recent years has been practically eliminated in favor of less harmful organic compounds. [Pg.86]

We shonld also utilize liquid hydrocarbons, which frequently accompany natural gas. These so-called natural gas liquids currently have little use besides their caloric heat value. They consist mainly of saturated straight hydrocarbons chains containing 3-6 carbon atoms, as well as some aromatics. As we found (Chapter 8), it is possible by superacidic catalytic treatment to upgrade these liquids to high-octane, commercially usable gasoline. Their use will not per se solve our long-... [Pg.210]

The correlations of rates with acidity functions provide a convenient means of treatii results, and their uses will frequently be illustrated. However, their status is empirical, for whilst the acidity dependence of nitration becomes less steep with increasing temperature, the slope of... [Pg.23]

Because of their use in the rubber industry various sulfenamido thiazoles (131) have been prepared. They are obtained in good yields through the oxidation of A-4-thiazoline-2-thiones (130) in aqueous alkaline solution in the presence of an amine or ammonia (Scheme 66) <123, 166, 255, 286, 308, 309). Other oxidizing agents have been proposed (54, 148. 310-313) such as iodine (152), chlorine, or hydrogen peroxide. Disulfides can also be used as starting materials (3141. [Pg.411]

One may find many publications in the literature on the theoretical aspects of thiazolium quaternary salts, because of the biological importance of thiamine and their use as catalysts for benzoin condensation. [Pg.30]

Metal-ammonia-alcohol reductions of aromatic rings are known as Birch reductions, after the Australian chemist Arthur J Birch who demonstrated their usefulness begin nmg m the 1940s... [Pg.439]


See other pages where Their Use is mentioned: [Pg.340]    [Pg.365]    [Pg.366]    [Pg.735]    [Pg.1484]    [Pg.1940]    [Pg.2061]    [Pg.283]    [Pg.388]    [Pg.167]    [Pg.1]    [Pg.136]    [Pg.495]    [Pg.120]    [Pg.159]    [Pg.204]    [Pg.55]    [Pg.576]   


SEARCH



Aminomethylenemalonates and their use

Aminomethylenemalonates and their use heterocyclic synthesis

Artificial Neural Networks and Their Use in Chemistry

Brief description of the currently used processes for decaffeination and their history

Common Variables Used in Thermodynamics and Their Associated Units

Density and Percent Composition Their Use in Problem Solving

Designing experiments for maximum information from cyclic oxidation tests and their statistical analysis using half normal plots (COTEST)

Discovery of SCFs and their Use as Solvents

Electrolytic Reactions and Their Use in Organic Synthesis

Elementary single-qubit gates and their implementations using RF pulses

Examples of Their Use as Tools for the Research Chemist

Free radicals and their reactions at low temperature using a rotating cryostat

Free radicals and their reactions at low temperature using a rotating cryostat, study

Free radicals, and their reactions at low temperature using a rotating

Genetic Algorithms and Their Use in Chemistry

Guanidine Derivatives and Their Use as Pesticides

Herbicidal Sulfonylureas, Their Preparation and Use

Heterogenizing Homogeneous Catalysts and Their Use in a Continuous Flow Reactor

Humidity Charts and Their Use

Instruments and their use

Ion-Conducting Polymers and Their Use in Electrochemical Sensors

Mechanistic studies, heat capacities of activation and their use

Models and Their Use

Notes on Carbodiimides and Their Use

Other techniques used in MS and their relation to pyrolysis

Oxadiazine Derivatives and Their Use as Pesticides

Oxime Derivatives and Their Use Thereof as Latent Acids

Performance Parameters of Fuel Cells Using Various Fuels and Their Typical Applications

Plastics Use in Healthcare and Their Possible Health Effects

Plastics and Polymer Composites A Perspective on Properties Related to their use in Construction

Polymers, and Their Complexes Used as Stabilizers for Emulsions

Reviews Concerning the Preparation of 0,0-Acetals and Their Use as Protecting Groups

SI units and their use

Separation of Lipoproteins and their Characterisation using HPLC-NMR

Study of free radicals and their reactions at low temperatures using a rotating cryostat

Substrate Analogs Their Use in Limiting

Summary Fischer Projections and Their Use

Test Systems and their Use

Textile Reinforcing Materials and Their Adhesive Systems Used in Rubber

Transition-Metal Containing Phase-Transfer Agents and Their Use in Synthesis

UNITS AND THEIR USE IN CALCULATIONS

Use of cells to determine mean activity coefficients and their dependence on ionic strength

Used Alloys and their Properties

Used to Describe the Interaction between Optical Centers and Their Surroundings

© 2024 chempedia.info