Met_OrgSynthesis

8.The most important types of industrial production involving the processing

and preparation of organic substances are the following:

1)Basic organic synthesis.

2)Processing of Combustible minerals.

3)Production of Polymer materials.

4)Processing of Farm Produce and the Food Industry.

5)Chemical Processing of Wood.

6)Refined organic synthesis.

Read the following paragraphs quickly to decide which paragraph goes with which type of production.

a)This embraces primarily the chemical processing of petroleum, natural gas and coal. The products are various grades of liquid fuel, lubricants and other materials, including some that are used for organic synthesis.

b)This consists chiefly of the production of plastics, rubbers, and chemical (artificial and synthetic) fibres.

c)This is the industry that provides the national economy with high tonnage products that are used directly as solvents (растворители), crop protection chemicals, detergents, refrigerants, dyes, medicines, etc.

Its products are substances of relatively simple composition and structure. They are the halogen derivatives of hydrocarbons, methyl, ethyl and other alcohols, phenol, formaldehyde and acetaldehyde, acetic acid and the higher acids, ethers and esters, nitro compounds, amines, and certain other substances.

d)This embraces the production of a very large number of most diverse substances, often of a highly complex structure. These are not such high-tonnage production processes as the industries of basic organic synthesis or polymer materials, but they are more “refined” chemically: to prepare the required substance, it is often necessary to conduct a whole series of rather complicated chemical reactions. Here we have the production of dyes, numerous pharmaceutical preparations, scents, organic reagents, photographic and cinematographic materials, etc. The products of basic organic synthesis are used extensively in the manufacture of all these goods.

e)This embraces the manufacture of cellulose, which is needed for the production of paper, cardboard, and viscose rayon; the hydrolysis of cellulose (wood pulp and agricultural waste) to produce glucose and ethyl alcohol, and the dry distillation of wood, which provides the food industry with acetic acid and certain other products.

f)This is exemplified by the processing of fats, starch-containing produce, and the production of margarine, molasses, and sugar. The production processes that come under this heading are for the most part not synthetic, although synthetic techniques are used in a few cases, as in the hydrogenation of fats.

9.Speak on major trends in Industrial Organic Chemistry.

10.How do you envisage the future of the organic chemistry?

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11. Find definition for each of the terms given.

e)Perkin's mauve, mauveine;

1.А soluble base or a solution of a base.

2.A cleaning or emulsifying agent made by reacting animal or vegetable fats or oils with potassium (калий) or sodium hydroxide.

3.Any of a class of naturally occurring soft greasy (жирный) solids that are esters of glycerol (глицерин) and certain fatty acids. They are present in some plants and in the adipose tissue (жировая ткань) of animals, forming a reserve energy source, and are used in making soap and paint and in the food industry.

4.A reddish-purple aniline dye.

5.Any salt or ester of cyanic acid (циановая кислота), containing the ion -OCN or the group –OCN.

6.A bitter crystalline alkaloid extracted from cinchona bark (хинная кора, кора хинного дерева), the salts of which are used as a tonic (тонизирующий), antipyretic (жаропонижающий), analgesic (анальгетик), etc., and in malaria therapy. Formula: C20H24N2O2.

7.A substance used for sticking objects together, such as glue (клей), cement, or paste.

8.Any one of a large number of synthetic usually organic materials that have a polymeric structure and can be moulded when soft and then set, esp. such a material in a finished state containing plasticizer (смягчитель, пластификатор), stabilizer, filler (за/наполнитель), pigments, etc. They are classified as thermosetting (such as Bakelite) or thermoplastic (such as PVC) and are used in the manufacture of many articles and in coatings, artificial fibres, etc.

9.A white crystalline compound widely used in the form of tablets to relieve (облегчать, ослаблять) pain and fever, to reduce inflammation, and to prevent strokes (приступ, инсульт). Formula: CH3COOC6H4COOH.

10.A drug containing arsenic, formerly used in the treatment of syphilis and related infections.

11.A colourless odourless substance used as an insecticide (инсектицид, средство от насекомых). It is toxic to animals and is known to accumulate in the tissues. It is now banned in the UK.

12.The name of a drug consisting of p-aminophenylarsenic acid. This organoarsenic compound was used in the late 19th and early 20th centuries, but is now considered dangerously toxic.

13.A white water-soluble crystalline compound with a saline taste and often an odour of ammonia, produced by protein metabolism and excreted in urine. A synthetic form is used as a fertilizer, animal feed, and in the manufacture of synthetic resins. Formula: CO(NH2)2 Also called: carbamide.

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TEXT 3. BUTLEROV’S THEORY OF THE CHEMICAL STRUCTURE OF ORGANIC COMPOUNDS. PART I

A certain number of organic substances were known to man and used by him in ancient times (acetic acid, ethyl alcohol, oils, starch, dyes, and some others). But the rapid advance of organic chemistry as a science began only in the XIX century, when the requirements of developing production caused many new organic substances to be discovered and investigated.

In the course of these discoveries there emerged facts that could not be interpreted in terms of the chemical theories current at the time.

In the fifties of the XIX century the valence of the chemical elements had become a scientific concept. The German chemist August Kekule established the quadrivalence of carbon. But in many organic compounds the valence of elements appeared to be invalid. Indeed, try to determine the valence of carbon, say, in ethane C2H6 or in propane C3H8 by the method familiar to you from inorganic chemistry. You will obtain a strange result: the carbon in ethane will appear to be trivalent (6/2), while in propane it will even seem to have a fractional valence (8/3).

Other problems arose too: why does the composition of the molecules in the hydrocarbon series increase every time precisely by one carbon atom and two hydrogen atoms; what is the reason for the diversity of organic compounds; why is it carbon and not some other element that forms so many compounds. Other facts also defied explanation, such as the existence of substances of absolutely identical composition and, hence, having the same molecular formula, but exhibiting markedly different properties.

All these and many other facts were explained by the theory advanced in the sixties of the XIX century by the great Russian chemist Alexander Butlerov.

The analysis of a vast amount of scientific data led Butlerov to the conclusion that the explanation of the baffling facts that had accumulated should be sought in the structure of molecules, made up of atoms. Contrary to the views of other scientists, who attached no significance to the structure of molecules and even regarded it as something that science could not probe, Butlerov maintained that chemical structure could fully be established and that only an understanding of the inner structure of molecules could resolve the deadlock in science and arm it with a theory that would enable it to make further successful progress.

Butlerov’s teachings about the structure of molecules came to be known as the theory of chemical structure.

The main points of the theory of chemical structure may be formulated as follows:

1.The arrangement of atoms in molecules is not a random one; they are linked to one another in a definite order, according to their valence.

2.The properties of substances depend not only on which atoms and in what amounts make up the molecules, but on the order in which these atoms are connected.

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Tasks on the text

1.Memorize the following words and word combinations.

2.Practise the pronunciation of the words. Revise their meanings.

3.Read, translate and define what parts of speech the words, their derivatives and related words belong to. Consult the dictionary, write out the meanings

that are new for you and memorize them.

Structure – structural – structureless; require – required – requirement; science

– scientific – scientist; valid – invalid – validation – validity – validness; determine – determined – determinate – determinative; fraction – fractional – fracture – fractural; molecule – molecular; analys(z)ation – analyse (analyze) – analyses – analysis; advance – advanced – advancement; datum – data; define – definite – definition.

4.Translate the following words and word combinations into Russian.

Rapid advance, in the course of, current at that time, to establish, to appear to be, indeed, hydrocarbon series, diversity, existence, to exhibit markedly different properties; a vast amount, to lead to the conclusion, baffling facts, contrary to the views, to attach no significance, to arm, to enable, to make progress, as follows, to one another, in a definite order, according to.

5.Look through the text and find the word combination “a fractional valence” and explain its meaning.

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6.Read paragraph 1, find the sentence with the Complex Object and translate it into Russian.

7.Read paragraph 3, find the sentences with the Complex Subject and translate them into Russian.

8.Read paragraph 4, find the sentence with the Emphatic construction and translate it into Russian.

9.Read the rest of the text and think of how many parts it can be divided into. What is each part about?

10.Translate the following into Russian.

1)В ходе этих открытий появились новые факты. 2) Мы попытаемся определить валентность углерода в этане. 3) Будет получен очень странный результат. 4) Великий русский химик выдвинул теорию, которая объяснила бы эти и многие другие факты. 5) Эти данные привели ученого к следующему выводу. 6) Только понимая внутреннее строение молекул, можно решить данную проблему. 7) Свойства вещества зависят также и от порядка, в котором его атомы соединяются.

11.Find suitable definition for each of the terms given.

a) Hydrocarbon; b) ethane; c) ethyl alcohol; d) acetic acid; e) propane; f) valence.

1.A colourless pungent (едкий) liquid, miscible (смешиваемый) with water, widely used in the manufacture of acetic anhydride (уксусный ангидрид), vinyl

acetate, plastics, pharmaceuticals, dyes, etc. Formula: CH3COOH. Systematic name: ethanoic acid (уксусная кислота).

2.Any organic compound containing only carbon and hydrogen, such as the alkanes, alkenes, alkynes, terpenes (терпены), and arenes.

3.The phenomenon of forming chemical bonds.

4.A colourless flammable liquid, the active principle of intoxicating drinks, produced by the fermentation of sugars, esp. glucose, and used as a solvent and in the manufacture of organic chemicals. Formula: C2H5OH.

5.A colourless flammable gaseous alkane found in petroleum and used as a fuel. Formula: CH3CH2CH3.

6.A colourless odourless flammable gaseous alkane obtained from natural gas and petroleum: used as a fuel and in the manufacture of chemicals. Formula: C2H6.

12. Discuss the following.

1.What motivated the rapid advance of organic chemistry as science at the beginning of the 19th century?

2.Can you give the baffling facts scientists faced in the middle of the 19th century.

3.What is the reason for the diversity of organic compounds?

4.Why do you think it is carbon and not some other element that forms so many compounds?

5.What was the contradiction in the views of A.Butlerov and other scientists?

6.What are the main points of the theory of chemical structure?

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TEXT 4. BUTLEROV’S THEORY OF THE CHEMICAL

STRUCTURE OF ORGANIC COMPOUNDS. PART II

Let us consider the first of the Butlerov’s theory principles as applied to hydrocarbons.

In what order are the atoms connected in a molecule of the simplest hydrocarbon, methane? We already know from inorganic chemistry that each hydrogen atom in it is connected with the carbon atom. It is easy to see that this must be the case. If we were to assume, for instance, that any two of the hydrogen atoms were connected with each other, this would mean they had exhausted their valences and could not link up with other atoms. The four hydrogen atoms can combine to form a CH4 molecule only through a quadrivalent carbon atom.

If we denote the valences of elements by a dash, we get the following picture of the bonds between the atoms in a methane molecule:

H

|

H— С —H

|

H

For all the carbon and hydrogen atoms in the ethane molecule to be linked up in a single particle, the carbon atoms must evidently be connected:

| |

—C — C —

| |

The carbon atoms in such a molecule have used up one valence unit each (out of the four that each atom has) to form the bond between themselves. This means they each have three valence units that are free, by means of which they hold six hydrogen atoms:

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The molecules of the other hydrocarbons with which we are familiar have a similar structure.

Now that you know the structure of these hydrocarbons, you will be able to provide answers yourself to some of the questions that baffled scientists at one time.

Is the valence of the elements violated in any of the compounds we have considered? No, carbon is quadrivalent in all of them. What accounts for the constant increment in the composition of hydrocarbon molecules? This is due to the fact that in the transition from one member of the series to the next the chain of atoms is each time extended by a CH2 link. What is the reason for the diversity of organic compounds? It is apparently the special ability of the carbon atoms to link up with one another, forming chains.

With a knowledge of the structure of hydrocarbons, it is easy to understand the similarity of their chemical properties and, specifically, the reason why they do not add other substances through reactions of addition. In the molecules of these substances all the valence units of the carbon atoms have been used up: they have been saturated with hydrogen atoms to the highest limit. Accordingly, any further addition of atoms to the carbon is impossible; the only possibilities are the substitution of, say, chlorine atoms for the hydrogen atoms or the destruction of the molecule. That is why the hydrocarbons we have been considering are called saturated, or limit, hydrocarbons. Another name for them is paraffins (from the Latin parum affinis, which means "little affinity").

Substances similar in structure and chemical properties, but differing in the composition of their molecules by one or several CH2 groups are called homologues and form homologous series. The hydrocarbons we have been considering – methane, ethane, propane, butane, etc. – are homologues; they form the homologous series of saturated hydrocarbons, or paraffins. The CH2 group of atoms is called the homologous increment.

Chemical formulae showing the arrangement of the atoms in a molecule are called structural formulae.

It should be borne in mind that structural formulae only show the order in which the atoms are connected, but do not show the arrangement of the atoms in space. Therefore, no matter how we write the formula of propane, it will still be one and the same substance, since the order in which the atoms are connected has not changed.

The structural formulae of substances are often written in a shortened form, such as CH3—CH2—CH3. Dashes in this case are used to show the bonds between carbon atoms, but not the bonds between carbon and hydrogen atoms.

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Tasks on the text

1.Memorize the following words and word combinations.

2.Find the equivalents for the words and word combinations in the left column from the column in the right.

3.Find the pairs of synonyms.

Particle, connect, feature, apparently, quadrivalent, account for, explain, evidently, link up, mean/define, exhaust, use up, property, hence, denote, tetravalent, fraction, therefore.

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4.Read, translate and define what parts of speech the words, their derivatives and related words belong to. Consult the dictionary, write out the meanings

that are new for you.

Valence – valency – valent – trivalent – quadrivalent; form – formula – formulae

– formulate; denote – denotative – denotation, denotement; substitute – substitution – substituent; consider – consideration – considerable; similar – similarity – similarly; violate – violation; destroy – destruct – destruction – destructive; homolog – homologous – homologue – homology; saturate – saturated – unsaturated – saturation; specific – specifically – specification – specificity – specified – specify; add – addition – additional – additive.

5.Find the right statement.

1)Structural formulae …

a)show the arrangement of the atoms in space;

b)show the arrangement of the atoms in a molecule;

c)cannot be written in a shortened form.

2)The reason for the diversity of organic compounds is …

a)the destruction of the molecules;

b)the rapid advance of organic chemistry;

c)the ability of the carbon atoms to form chains.

3)Paraffins …

1)Let us consider the first of the Butlerov’s theory principles as applied to hydrocarbons.

2)It is easy to see that this must be the case.

3)If we were to assume, for instance, that any two of the hydrogen atoms were connected with each other, this would mean they had exhausted their valences and could not link up with other atoms.

4)What accounts for the constant increment in the composition of hydrocarbon molecules?

5)This is due to the fact that in the transition from one member of the series to the next the chain of atoms is each time extended by a CH2 link.

6)It should be born in mind that structural formulae only show the order in which the atoms are connected, but do not show the arrangement of the atoms in space.

7)Therefore, no matter how we write the formula of propane, it will still be one and the same substance, since the order in which the atoms are connected has not changed.

6.Look through the text. Find the sentences with the Adverbial Clauses of Condition and analyse them. Translate the sentences into Russian.

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7.Read the text and answer the following questions.

1)What substances are called homologues?

2)What is the general formula of the hydrocarbons of the methane homologous series?

3)Why are methane and its homologues called saturated hydrocarbons?

4)How do the physical properties of the substances in the homologous series of saturated hydrocarbons change? Give examples.

5)Which homologue of methane has a density approximately equal to that of air?

8.Find suitable definition for each of the terms given.

a) Butane; b) chemical bond; c) chlorine; d) homologue; e) methane; f) paraffin(e).

1.A liquid mixture consisting mainly of alkane hydrocarbons with boiling points in the range 150°-300 °C, used as an aircraft fuel, in domestic heaters (домашний обогреватель), and as a solvent (растворитель).

2.A colourless odourless flammable gas, the simplest alkane and the main constituent of natural gas: used as a fuel. Formula: CH4.

3.A toxic pungent (ядовитый) greenish-yellow gas of the halogen group; occurs only in the combined state, mainly in common salt: used in the manufacture of many organic chemicals, in water purification, and as a disinfectant

(дезинфектант) and bleaching agent (отбеливатель). Symbol: Cl; atomic no.: 17; atomic wt.: 35.4527; valency: 1, 3, 5, or 7; density: 3.214 kg/m3; relative density: 1.56; melting pt.: -101.03 °C; boiling pt.: -33.9 °C.

4.Any homologous compound.

5.A colourless flammable gaseous alkane that exists in two isomeric forms, both of which occur in natural gas. The stable isomer, n-butane, is used mainly in the manufacture of rubber and fuels. Formula: C4H10.

6.A mutual attraction between two atoms resulting from a redistribution of their outer electrons.

9.Translate the following sentences into Russian.

Этан представляет собой химическое соединение с формулой C2H6.. Это единственный двууглеродный алкан, то есть алифатический углеводород. При стандартных температуре и давлении этан – газ без цвета и запаха. В промышленном масштабе этан выделяют из природного газа и получают как попутный продукт нефтепереработки.

Cегодня этан – важное нефтехимическое сырье (feedstock); он отделяется от других компонентов природного газа на большинстве хорошо разработанных месторождений. Этан также может быть выделен из нефтяного (попутного) газа (petroleum gas), смеси газообразных углеводородов, которая возникает в виде попутного продукта нефтепереработки. Этан используется как катализатор для ускорения (to boost up) реакции; и в производстве этилена посредством парового (термического) крекинга.

10.Make a short report on Butlerov’s theory.

11.Do you think whether it is important for you as a specialist to know Butlerov’s theory? Give your arguments.

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