Aniline Dyes Information

Aniline
Aniline, phenylamine or aminobenzene (C6H5NH2) is an organic chemical compound which is a primary aromatic amine consisting of a benzene ring and an amino group. The chemical structure of aniline is shown at the right.
Synthesis

Aniline can be produced from benzene in two steps. First, benzene is nitrated (reacted with nitric acid, a form of electrophilic substitution reaction) to give nitrobenzene. Second, the nitrobenzene is reduced to give aniline. A variety of reducing agents are effective for the reduction, including H2 (with a catalyst), hydrogen sulfide, iron, zinc, or tin.

Many derivatives of aniline can be prepared similarly.In commerce three brands of aniline are distinguished—aniline oil for blue, which is pure aniline; aniline oil for red, a mixture of equimolecular quantities of aniline and ortho- and para-toluidines; and aniline oil for safranine, which contains aniline and ortho-toluidine, and is obtained from the distillate (échappés) of the fuchsine fusion. Monomethyl and dimethyl aniline are colourless liquids prepared by heating aniline, aniline hydro-chloride and methyl alcohol in an autoclave at 220°C. They are of great importance in the colour industry. Monomethyl aniline boils at 193-195°C; dimethyl aniline at 192°C.
Properties

Aniline is oily and, although colourless, it can be slowly oxidized and resinified in air to form impurities which can give it a red-brown tint. Its boiling point is 184 °C and its melting point is -6 °C. It is a liquid at room temperature.

Like most volatile amines, it possesses a somewhat unpleasant odour of rotten fish, and also has a burning aromatic taste; it is a highly acrid poison. It ignites readily, burning with a large smoky flame.

Chemically, aniline is a weak base. Aromatic amines such as aniline are generally much weaker bases than aliphatic amines. Aniline reacts with strong acids to form salts containing the anilinium (or phenylammonium) ion (C6H5-NH3+), and reacts with acyl halides (such as acetyl chloride (ethanoyl chloride), CH3COCl) to form amides. The amides formed from aniline are sometimes called anilides, for example CH3-CO-NH-C6H5 is acetanilide, for which the modern name is N-phenyl ethanamide.

The sulphate forms beautiful white plates. Although aniline is but feebly basic, it precipitates zinc, aluminium and ferric salts, and on warming expels ammonia from its salts. Aniline combines directly with alkyl iodides to form secondary and tertiary amines; boiled with carbon disulphide it gives sulphocarbanilide (diphenyl thio-urea), CS(NHC6H5)2, which may be decomposed into phenyl mustard-oil, C6H5CNS, and triphenyl guanidine, C6H5N: C(NHC6H5)2. Sulphuric acid at 180° C gives sulphanilic acid, NH2.C6H4.SO3H. Anilides, compounds in which the amino group is substituted by an acid radical, are prepared by heating aniline with certain acids; antifebrin or acetanilide is thus obtained from acetic acid and aniline. The oxidation of aniline has been carefully investigated. In alkaline solution azobenzene results, while arsenic acid produces the violet-colouring matter violaniline. Chromic acid converts it into quinone, while chlorates, in the presence of certain metallic salts (especially of vanadium), give aniline black. Hydrochloric acid and potassium chlorate give chloranil. Potassium permanganate in neutral solution oxidizes it to nitrobenzene, in alkaline solution to azobenzene, ammonia and oxalic acid, in acid solution to aniline black. Hypochlorous acid gives para-amino phenol and para-amino diphenylamine.

Like phenols, aniline derivatives are highly reactive in electrophilic substitution reactions. For example, sulfonation of aniline produces sulfanilic acid, which can be converted to sulfanilamide. Sulfanilamide is one of the sulfa drugs which were widely used as antibacterials in the early 20th century.

Aniline and its ring-substituted derivatives react with nitrous acid to form diazonium salts. Through these, the -NH2 group of aniline can be conveniently converted to -OH, -CN, or a halide.
Uses

Originally the great commercial value of aniline was due to the readiness with which it yields, directly or indirectly, valuable dyestuffs. The discovery of mauve in 1858 by William Perkin was the first of a series of dyestuffs which are now to be numbered by hundreds. Reference should be made to the articles dyeing, fuchsine, safranine, indulines, for more details on this subject. In addition to dyestuffs, it is a starting-product for the manufacture of many drugs such as Acetaminophen/Paracetamol (Tylenol).

Currently the largest market for aniline is preparation of 4,4′-MDI, some 85% of aniline serving this market. Other uses include rubber processing chemicals (9%), herbicides (2%), and dyes and pigments (2%). [1]
History

Aniline was first isolated from the destructive distillation of indigo in 1826 by Otto Unverdorben (Pogg. Ann., 1826, 8, p. 397), who named it crystalline. In 1834, Friedrich Runge (Pogg. Ann., 1834, 31, p. 65; 32, p. 331) isolated from coal tar a substance which produced a beautiful blue colour on treatment with chloride of lime; this he named kyanol or cyanol. In 1841, C. J. Fritzsche showed that by treating indigo with caustic potash it yielded an oil, which he named aniline, from the specific name of one of the indigo-yielding plants, Indigofera anil, anil being derived from the Sanskrit nīla, dark-blue, and nīlā, the indigo plant. About the same time N. N. Zinin found that on reducing nitrobenzene, a base was formed which he named benzidam. August Wilhelm von Hofmann investigated these variously prepared substances, and proved them to be identical (1855), and thenceforth they took their place as one body, under the name aniline or phenylamine.

Its first industrial-scale use was in the manufacture of mauveine, a purple dye discovered in 1856 by William Henry Perkin.

p-toluidine, an aniline derivative, can be used in qualitative analysis to prepare carboxylic acid derivitives.
Toxicology

Aniline is toxic by inhalation of the vapour, absorption through the skin or swallowing. It causes headache, drowsiness, cyanosis, mental confusion and in severe cases can cause convulsions. Prolonged exposure to the vapour or slight skin exposure over a period of time affects the nervous system and the blood, causing tiredness, loss of appetite, headache and dizziness.[2]

Oil mixtures containing rapeseed oil denatured with aniline have been clearly linked by epidemiological and analytic chemical studies to the toxic oil syndrome that hit Spain in the spring and summer of 1981, in which 20,000 became acutely ill, 12,000 were hospitalized, and more than 350 died in the first year of the epidemic. The precise etiology though remains unknown.

Some authorities class aniline as a carcinogen, although the IARC lists it in Group 3 (not classifiable as to its carcinogenicity to humans) due to the limited and contradictary data available.
More Information Visit US: Copper CNC Machine Chemical Industry Heat Exchangers Bearing

February 28, 2006 | Filed Under Dyes, Ammonia, Acids | Leave a Comment 

Preservative Information

A preservative is a natural or synthetic chemical that is added to products such as foods, pharmaceuticals, paints, biological samples, etc. to retard spoilage, whether from microbial growth, or undesirable chemical changes.

Preservatives may be added to wood to prevent the growth of fungi as well as to repel insects and termites. Typically copper, borate, and petroleum based chemical compounds are used. For more information on wood preservatives see timber treatment, lumber and creosote.

Preservative food additives are often used alone, or in conjunction with other methods of food preservation. A distinction is sometimes made between anti-microbial preservatives which function by inhibiting the growth of insects, bacteria and fungi, and antioxidants, which inhibit the oxidation of food constituents. Common anti-microbial preservatives include sodium nitrate, sodium nitrite, sulfites, (sulfur dioxide, sodium bisulfate, potassium hydrogen sulfate, etc.) and disodium EDTA. Antioxidants include BHA and BHT. Other preservatives include formaldehyde (usually in solution), glutaraldehyde, diatomaceous earth (kills insects), ethanol and methylchloroisothiazolinone. The benefits and safety of many artificial food additives (including preservatives) are the subject of debate among academics specializing in food science and toxicology.

Some methods of food preservation involve the use of salt, sugar or vinegar, which are sometimes considered to be foods rather than additives.

More Information Visit US: Copper CNC Machine Chemical Industry Heat ExchangersBearing

February 28, 2006 | Filed Under Preservatives, Paint Thinners, Chemical | Leave a Comment 

Chemical industry information

The chemical industry refers to industry involved in the production of chemicals with high economic impact. These include petrochemicals, agrochemicals, pharmaceuticals, polymers, paints, and oleochemicals. Chemical processes are used, including chemical reactions to form new substances, separations based on properties such as solubility or ionic charge, and distillations, in addition to transformations by heating and other methods.

Chemical industries involve the processing of, or change in, raw materials obtained by mining, and agriculture among other supply sources, into materials and substances that are useful on their own, or in other industries. The food processing industries are generally not included in the term “chemical industry”.

More Information Visit US: Copper CNC Machine Chemical Industry Heat ExchangersBearing

February 25, 2006 | Filed Under Chemical | Leave a Comment 

A Quality Commitment Leads Precious Metal Refining Performance With Chemicals Into The Next Millennium

“Quality” is a somewhat subjective term that has numerous definitions. It�s purpose and meaning is virtually at the mercy of the term�s user and the intended recipient depending on the context in which it is used; the industry to which it is applied; and, the overall intent of its application. However, defining quality and the standards for measuring such has taken on a far more significant role in a global marketplace, especially for the jewelry industry.
The term quality and the demand for such is the standard that all manufacturers of fine jewelry judge themselves, their competitors, their products and their vendors. It is the quality of fine gems used, the craftsmanship in each finished product, the unique style and presentation that individually and collectively define the overall image of any manufacturer. It is this “quality image” that is of critical concern to every fine jewelry manufacturer, and that which can ultimately drive or demote its success.
But quality extends far beyond the sale of fine jewelry product. The manufacturer of quality jewelry must demand quality not only from itself and its raw material suppliers but from those who are charged with the responsibility of servicing the manufacturer outside and beyond the parameters of the manufacturing operation. That is, people who process a manufacturer�s waste material into usable gold � commonly known as your precious metal refiner.
Quality driven systems are becoming mandatory in many business environments throughout the world. A quality standard can and should be applied to precious metal refining, this critical area of the jewelry industry.
The usual questions of accountability, security, and turnaround times should be accompanied by the inquiry as to “How does an individual refiner monitor the inner workings of his own business?
” What does your refiner do to document refining procedures, assay procedures, and equipment calibration?
. In short, the question can be What Quality Standard does the refiner hold himself to and who monitors that standard?

What is a Quality Management System?
A quality management system is a set of standards that are implemented within a business that govern every aspect of that individual business. Procedures are documented, standards of weights and measures are qualified and monitored, methods of processing are documented, and a corporate commitment to quality and enforcement is made. A registered outside quality auditor such as N.Q.A. (National Quality Assurance USA) monitors the quality system.
To remain competitive in a world that demands superior products and service, individual companies � especially precious metal refiners � must respond by incorporating a quality management system such as or equal to the standards established by the International Organization for Standardization (ISO), a world-recognized, independent international agency which overseas the ISO 9000 Quality Systems standard. The ISO standards provide the discipline essential to develop, implement and maintain an effective quality management system. An ISO 9000 Quality Management System provides the impetus needed for a company to provide quality service and products to its customers and supply the resources needed for continuous improvement. Adopting such a system works to remove the guesswork, mystery and discomfort commonly associated with the relationship between a precious metals refiner and fine jewelry manufacturers.
The cost to a refiner of adopting a quality system is overshadowed by the confidence a customer gains in knowing that there are standards that must be adhered to and an auditor that must be answered to on a regular basis.
Quality as it relates to refining. In an industry that has operated virtually without regulation or standard operating procedures, precious metal refining has evolved through the years as a business based initially on trust and mistrust. At the outset of any manufacturer�s initiation of a refiner relationship, the primary consideration is usually that of “how much gold” will the refining lot yield. A more appropriate and productive approach would be to evaluate the quality of the gold refining process in much the same way the manufacturer might examine the quality of its own products and operating practices. A precious metal refiner must be held to similar quality standards as those that apply to the fine jewelry manufacturer. The refiner to improve and enhance the efficiency and effectiveness of its operation, which will ultimately have a positive impact on each of its customers, can implement the independent quality standards of a quality management system. By adoption of a quality management system, the refiner accepts and adheres to a certification and monitoring process that will ensure consistent, predictable procedures of its operation.
How does the quality system benefit the customer?
Procedures governing handling, sampling, assaying, processing, and settlement become written documents and must be adhered to, they become accessible to the customer. The customer knows that to keep his certification, an audit by an objective third party annually, combined with numerous internal audits are required by all quality systems. Failing to maintain certification becomes public record.
What is ISO 9000?
ISO 9000 is a series of standards published worldwide that define a framework of minimum requirements for the implementation of a quality system. These ISO 9000 standards have been adopted worldwide as suitable criteria for assessment and registration of companies by independent, accredited third-party organizations called, “Registrars”. With an ongoing third-party review of the participating refiner by its ISO registering agency, customers of the refiner benefit from the integrity of the standards applied to the refining process by not only gaining an improved relationship with the refiner, but more importantly in dollars and cents gained at their bottom line.
The direct affect of implementing a Quality Management System for the refiner will include the following benefits:

Manufacturers share “cradle to grave” responsibility. There are other reasons for manufacturers to consider the benefits of quality standards for refining. Not only is the quantity of gold in each refining lot at stake, environmental compliance is also critical. It is important for manufacturers to evaluate a refiner�s ability to accurately determine gold quantity. However, refiners are also considered “treatment companies” who must document the proper handling and disposal of any and all regulated hazardous material they have processed. Liability for any penalties or fines resulting from a refiner�s violation of any local, state, or Federal government regulations and reporting procedures can be applied to the generator of the waste material, i.e., the jewelry manufacturer.
A refiner must handle the material responsibly and in accordance with any pertinent laws and regulation. However, if a manufacturer is sending regulated, hazardous material to the refiner the manufacturer must take responsibility for knowing the capability and commitment the refiner has to environmental compliance. A manufacturer should visit the refiner to not only represent his material, but more importantly to ask for and meet the refiner�s environmental affairs representative. An initial environmental meeting should include a list of customer references from the refiner, a review of environmental pollution control equipment and the examination of the refiner�s compliance records. A manufacturer should question the refiner�s relationship with all pertinent regulatory agencies and should be provided with contact names and telephone numbers. Manufacturers should be encouraged to check the refiner�s history of performance with regulatory agencies including any record of spills at the refiner site or any agency citations the refiner may have received. Annual environmental audits should include a review of environmental compliance records plus the refiner�s Occupational Safety and Health Association (OSHA) records, including worker injuries and loss work days. A pattern of re-occurring problems may indicated a need for better compliance or if loss work days are high, the refiner may have a problem processing customer work in a timely fashion both of which could have impact on the quality of the manufacturer�s operation.
When visiting a refinery, the customer can use the visit to more than witness the process of his material. It is the perfect environment to establish a positive working relationship with the refiner by taking a few extra minutes to ask some pertinent questions.
A manufacturer needs to apply the same quality expectations it may have for its own product manufacturing to that of a refiner�s operation. Below is a checklist of items to consider when visiting the refiner.

  1. Are the standards for weights and measures all calibrated on a nationally accepted, systematic basis at defined intervals?
  2. What records of calibration are kept, on what equipment, and are they readily available for review?
  3. Are the standards used for calibration traceable to and recognized by an international organization such as the National Institute of Standards and Technology (NIST)?
  4. What are the refiner�s laboratory standards of quality such as,
    1. Are there published, standard procedures for each type of material assayed including solution, resins, and polishing dust?
    2. Are these standards readily available for review?
    3. Is it clear that no deviations are allowed?
  1. Does the refiner have an environmental affairs specialist?
  2. What are the refiner�s policies and procedures for handling hazardous material, including
    1. pollution control equipment used?
    2. full and complete record keeping?
    3. is this information readily available for review?
  1. What is the refiner�s history of environmental compliance?
  2. What is the refiner�s history of OSHA compliance?

An enduring commitment leads to success.
The fine jewelry manufacturing and precious metal refining industries have gone through a significant transition over the last decade. Manufacturing companies in the jewelry industry have experienced unrelenting demand from the marketplace to improve quality and service delivery while at the same time reduce costs. The effort to accomplish these sometimes highly aggressive goals has put great pressure on vendors and suppliers to share in the responsibilities of providing value-added goods and services to a global market.
Precious metal refiners must recognize and understand the manufacturer�s needs for cost, value, reliability, accuracy and safety in handling a customer�s precious metals. Manufacturers must place primary emphasis on quality standards for its refiners and make these expectations well known throughout the industry. Adopting a commitment to quality standard and adhering to the practices of a sound quality management program will enhance and improve the refiner�s service and production which, in turn, will benefit the fine jewelry industry overall. It is not just a formula for success, it is a prediction for survival in a highly competitive marketplace.
More Information Visit US: Copper CNC Machine Chemical Industry Heat Exchangers Bearing

February 24, 2006 | Filed Under Chemical | Leave a Comment 

Catalyst Information

A catalyst (Greek: καταλύτης, catalytÄ“s) is a substance that accelerates the rate (speed) of a chemical reaction (see also catalysis). Chemical catalysts, the focus of this article, participate in reactions but are neither chemical reactants nor chemical products. More generally, one may sometimes call anything which accelerates a reaction without itself being consumed or transformed a catalyst (for example, a “catalyst for political change”).
Catalysts and reaction energetics

Catalysts enable reactions to occur much faster or at lower temperatures because of changes that they induce in the reactants. Catalysts provide an alternative pathway of lower activation energy, for a reaction to proceed whilst remaining chemically unchanged themselves. This can be observed on a Boltzmann distribution and energy profile diagram. This means that catalysts reduce the amount of energy needed to start a chemical reaction. Molecules that would not have had the energy to react or that have such low energies that they probably would have taken a long time to react are able to react in the presence of a catalyst. Thus, more molecules that need to gain less energy to react will go through the chemical reaction.

Catalysts cannot make energetically unfavorable reactions possible — they have no effect on the chemical equilibrium of a reaction because the rate of both the forward and the reverse reaction are equally affected.
Types of catalysts

Catalysts can be either heterogeneous or homogeneous. Heterogeneous catalysts are present in different phases from the reactants (e.g. a solid catalyst in a liquid reaction mixture), whereas homogeneous catalysts are in the same phase (e.g. a dissolved catalyst in a liquid reaction mixture). A simple model for heterogeneous catalysis involves the catalyst providing a surface on which the reactants (or substrates) temporarily become adsorbed. Bonds in the substrate become weakened sufficiently for new bonds to be created. The bonds between the products and the catalyst are weaker, so the products are released.

For example, in the Haber process to manufacture ammonia, finely divided iron acts as a heterogenous catalyst. The metal uses active sites to allow partial weak bonding to the reactant gases, which are adsorbed onto the metal surface. As a result, the bond within the molecule of a reactant is weakened and the reactant molecules are held in close proximity to each other. In this way the particularly strong triple bond in nitrogen is weakened and the hydrogen and nitrogen molecules are brought closer together than would be the case in the gas phase, so the rate of reaction increases.

Other heterogenous catalysts include vanadium V oxide in the Contact process, nickel in the manufacture of margarine, alumina and silica in the cracking of alkanes and platinum rhodium palladium in catalytic converters.

In car engines, incomplete combustion of the fuel produces carbon monoxide, which is toxic. The electric spark and high temperatures also allow the oxygen and nitrogen to react to form nitrogen monoxide, which is acidic. Catalytic converters reduce such emissions by adsorbing CO and NO onto the catalytic surface, where the gases undergo a redox reaction. Carbon dioxide and nitrogen are desorbed from the surface and emitted as relatively harmless gases:

2CO + 2NO → 2CO(2) + N(2)

Example of homogeneous catalysts are H+(aq) which acts as a catalyst in esterification and chlorine free radicals in the break down of ozone. Chlorine free radicals are formed by the action of ultraviolet radiation on chlorofluorocarbons (CFCs). They react with ozone forming oxygen molecules and regenerating chlorine free radicals:

Cl(.) + O(3) → ClO(.) + O(2)

ClO(.) + O → Cl(.) + O(2)

N.B. Full stops in brackets denote free radicals that should be superscripted. Numbers in brackets should be subscripted

Homogeneous catalysts generally react with one or more reactants to form a chemical intermediate that subsequently reacts to form the final reaction product, in the process regenerating the catalyst. The following is a typical reaction scheme, where C represents the catalyst:

A + C → AC (1)

B + AC → AB + C (2)

Although the catalyst (C) is consumed by reaction 1, it is subsequently produced by reaction 2, so for the overall reaction:

A + B + C → AB + C

the catalyst is neither consumed nor produced. Enzymes are biocatalysts. Use of “catalyst” in a broader cultural sense is in rough analogy to the sense described here. Other biocatalysts are ribozymes and deoxyribozymes.
Poisoning a Catalyst

A catalyst can be poisoned if another compound reacts with it and bonds chemically, but does not release. This effectively destroys the usefulness of the catalyst, as it cannot participate in the reaction with which it was supposed to catalyse, just like Raney nickel catalyst has reduced activity when it is in combination with mild steel. The loss in activity of catalyst can be overcome by having a lining of epoxy or other substances .
Commonly used catalysts

Estimates are that 60% of all commerically produced chemical products involve catalysts at some stage in the process of their manufacture.[1] Some of the most famous catalysts ever developed are the Ziegler-Natta catalysts used to mass produce polyethylene and polypropylene. Probably the best-known catalytic reaction is the Haber process for ammonia synthesis, where ordinary iron is used as a catalyst. Catalytic converters made from platinum and rhodium break down some of the more harmful byproducts of automobile exhaust. The most effective catalysts are usually transition elements.
More Information Visit US: Copper CNC Machine Chemical Industry Heat Exchangers Bearing

February 23, 2006 | Filed Under Catalysts, Ammonia, Acids | Leave a Comment 

Carbon Information

Carbon is a chemical element in the periodic table that has the symbol C and atomic number 6. An abundant nonmetallic, tetravalent element, carbon has several allotropic forms:

* Diamond : Hardest known natural mineral. Structure: each atom is bonded tetrahedrally to four others, making a 3-dimensional network of puckered six-membered rings of atoms.
* Graphite : One of the softest substances. Structure: each atom is bonded trigonally to three other atoms, making a 2-dimensional network of flat six-membered rings; the flat sheets are loosely bonded.
* Fullerenes : Structure: comparatively large molecules formed completely of carbon bonded trigonally, forming spheroids (of which the best-known and simplest is the buckminsterfullerene or buckyball).
* Chaoite : A mineral believed to be formed in meteorite impacts.
* Lonsdaleite : A corruption of diamond. Structure: similar to diamond, but forming a hexagonal crystal lattice.
* Amorphous carbon : A glassy substance. Structure: an assortment of carbon molecules in a non-crystalline, irregular, glassy state.
* Carbon nanofoam : An extremely light magnetic web. Structure: a low-density web of graphite-like clusters, in which the atoms are bonded trigonally in six- and seven-membered rings.
* Carbon nanotubes : Tiny tubes. Structure: each atom is bonded trigonally in a curved sheet that forms a hollow cylinder.
* Aggregated diamond nanorods : The most recently discovered allotrope and the hardest substance known to man.
* Lamp black : Consists of small graphitic areas. These areas are randomly distributed, so the whole structure is isotropic.
* ‘Glassy carbon’ : An isotropic substance that contains a high proportion of closed porosity. Unlike normal graphite, the graphitic layers are not stacked like pages in a book, but have a more random arrangement.

Carbon fibers are similar to glassy carbon. Under special treatment (stretching of organic fibers and carbonization) it is possible to arrange the carbon planes in direction of the fiber. Perpendicular to the fiber axis there is no orientation of the carbon planes. The result are fibers with a higher specific strength than steel.

Carbon occurs in all organic life and is the basis of organic chemistry. This nonmetal also has the interesting chemical property of being able to bond with itself and a wide variety of other elements, forming nearly 10 million known compounds. When united with oxygen it forms carbon dioxide which is absolutely vital to plant growth. When united with hydrogen, it forms various compounds called hydrocarbons which are essential to industry in the form of fossil fuels. When combined with both oxygen and hydrogen it can form many groups of compounds including fatty acids, which are essential to life, and esters, which give flavor to many fruits. The isotope carbon-14 is commonly used in radioactive dating.

Notable characteristics

Carbon is a remarkable element for many reasons. Its different forms include one of the softest (graphite) and one of the hardest (diamond) substances known. Moreover, it has a great affinity for bonding with other small atoms, including other carbon atoms, and its small size makes it capable of forming multiple bonds. Because of these properties, carbon is known to form nearly ten million different compounds, the large majority of all chemical compounds. Carbon compounds form the basis of all life on Earth and the carbon-nitrogen cycle provides some of the energy produced by the sun and other stars. Moreover, carbon has the highest melting/sublimation point of all elements. At atmospheric pressure it has no actual melting point as its triple point is at 10 MPa (100 bar) so it sublimates above 4000 K. Thus it remains solid at higher temperatures than the highest melting point metals like tungsten or rhenium, regardless of its allotropic form.

Carbon was not created in the Big Bang due to the fact that it needs a triple collision of alpha particles (helium nuclei) to be produced. The universe initially expanded and cooled too fast for that to be possible. It is produced, however, in the interior of stars in the horizontal branch, where stars transform a helium core into carbon by means of the triple-alpha process. It was also created in a multi atomic state.

Applications

Carbon is a vital component of all known living systems, and without it life as we know it could not exist (see alternative biochemistry). The major economic use of carbon is in the form of hydrocarbons, most notably the fossil fuels methane gas and crude oil (petroleum). Crude oil is used by the petrochemical industry to produce, amongst others, gasoline and kerosene, through a distillation process, in refineries. Crude oil forms the raw material for many synthetic substances, many of which are collectively called plastics.

Other uses

* The isotope carbon-14 was discovered in February 27, 1940 and is used in radiocarbon dating.
* Graphite is combined with clays to form the ‘lead’ used in pencils.
* Diamond is used for decorative purposes, and also as drill bits and other applications making use of its hardness.
* Carbon is added to iron to make steel.
* Carbon is used as a neutron moderator in nuclear reactors.
* Graphite carbon in a powdered, caked form is used as charcoal for cooking, artwork and other uses.
* Activated charcoal is used in medicine (as powder or compounded in tablets or capsules) to absorb toxins or poisons from the digestive system.

The chemical and structural properties of fullerenes, in the form of carbon nanotubes, has promising potential uses in the nascent field of nanotechnology. Nanoparticles might however be toxic.
More Information Visit US : Chemical Industry Copper CNC Machine Hydraulic Equipment

February 21, 2006 | Filed Under Carbon, Chemical | Leave a Comment 

Ammonium bicarbonate

Ammonium Bicarbonate also called bicarbonate of ammonia, ammonium hydrogen carbonate, hartshorn, or powdered baking ammonia is the bicarbonate salt of ammonia.

Ammonium bicarbonate is formed as shown above and also by passing carbon dioxide through a solution of the normal compound, when it is deposited as a white powder, which has no smell and is only slightly soluble in water. The aqueous solution of this salt liberates carbon dioxide on exposure to air or on heating, and becomes alkaline in reaction. The aqueous solutions of all the carbonates when boiled undergo decomposition with liberation of ammonia and of carbon dioxide:

NH4HCO3 → NH3 + H2O + CO2

Properties

At room temperature Ammonium bicarbonate is a white, crystalline powder with a slight odour of ammonia that can dissolve in water to give a mildly alkaline solution. It is however insoluble in acetone and alcohols. Ammonium bicarbonate decomposes at 36 to 60 °C into ammonia, carbon dioxide and water vapor in an endothermic process (as it is with many ammonium salts) and so causes a drop in the temperature of the water. When reacted with acids carbon dioxide is produced, while reactions with alkalis give ammonia.

Uses

Ammonium bicarbonate was used in the food industry as a raising agent (e.g. for gingerbread, Chinese Youtiao) before the introduction of baking soda. This compound is used as a component in the production of fire-extinguishing compounds, pharmaceuticals, dyes, pigments and it is also a basic fertilizer being a source of ammonia. Ammonium bicarbonate is still widely used in the plastic and rubber industry, in the manifacture of ceramics, in chrome leather tanning and for the synthesis of catalysts.lll

Safety

Ammonium bicarbonate is irritant to the skin, eyes and respiratory system.

More Information Visit Us : Chemical Industry Copper CNC Machine Business Industry

February 20, 2006 | Filed Under Ammonium, Ammonia | Leave a Comment 

Ammonium acetate

Ammonium acetate is the salt of ammonia and acetic acid.

Properties

It is highly hygroscopic. It decomposes easily at high temperatures into acetamide. It melts at 114 C.

Reactions

Ammonium acetate is useful in the Kovengel reaction. It is often used with acetic acid to create an acidic buffer system.

Synthesis of Ammonium Acetate

Ammnonium acetate can be obtained easily by the reaction with of acetic acid with ammonia.

CH3COOH + NH3 → CH3COONH4

At home it can be made by reacting ammonium hydroxide with dilute acetic acid and evaporating the water. As long as the heat applied is kept at a minimum, the substance would not decompose. Applying a vacuum would improve removal of the water. It should must then be dried.

More Information Contact Us : Chemical Copper CNC Machine Business Industry

February 20, 2006 | Filed Under Ammonium, Acids | Leave a Comment 

Potassium History Information

The metal is the seventh most abundant and makes up about 1.5 % by weight of the earth’s crust. Potassium is an essential constituent for plant growth and it is found in most soils. It is also a vital element in the human diet.

Potassium is never found free in nature, but is obtained by electrolysis of the chloride or hydroxide, much in the same manner as prepared by Davy. It is one of the most reactive and electropositive of metals and, apart from lithium, it is the least dense known metal. It is soft and easily cut with a knife. It is silvery in appearance immediately after a fresh surface is exposed.

It oxidises very rapidly in air and must be stored under argon or under a suitable mineral oil. As do all the other metals of the alkali group, it decomposes in water with the evolution of hydrogen. It usually catches fire during the reaction with water. Potassium and its salts impart a lilac colour to flames.

Isolation

Here is a brief summary of the isolation of potassium.Potassium would not normally be made in the laboratory as it is so readily available commercially. All syntheses require an electrolytic step as it is so difficult to add an electron to the poorly electronegative potassium ion K+.

Potassium is not made by the same method as sodium as might have been expected. This is because the potassium metal, once formed by electrolysis of liquid potassium chloride (KCl), is too soluble in the molten salt.

cathode: K+(l) + e- K (l)

anode: Cl-(l) 1/2Cl2 (g) + e-

Instead, it is made by the reaction of metallic sodium with molten potassium chloride at 850°C.

Na + KCl K + NaCl

This is an equilibrium reaction and under these conditions the potassium is highly volatile and removed from the system in a form relatively free from sodium impurities, allowing the reaction to proceed.

More Information Visit US: Chemical Metal CNC Machine Business Industry

February 18, 2006 | Filed Under Potassium | Comments Off 

Paint Thinners Turpentine substitute

Turpentine substitute is a minerals based replacement for the vegetable based organic solvent turpentine. It is a hydrotreated light distillate of petroleum, which forms a clear transparent liquid at room temperature. It is a complex mixture of highly refined hydrocarbon distillates mainly in the C9-C16 range. The liquid is highly volatile and the vapours are flammable.

As the name suggests it is a widely available and cheaper substitute for turpentine. It is commonly used as an organic solvent in painting and decorating, for thinning oil based paint and cleaning brushes. Also known as turps substitute, mineral turpentine, or just turps, causing confusion with genuine turpentine.

More Details Visit US: Chemical Metal CNC Machine Business Industry

February 17, 2006 | Filed Under Organic, Paint Thinners | Comments Off 

Next Page →