Structural features of organic compounds. Features of the structure of organic substances
Features of organic compounds
Elements of organic chemistry. Polymers
Features, theory chemical structure and classification of organic compounds
Carbon compounds (except for the simplest ones) are called organic. These are either natural or artificially obtained substances. Organic chemistry is the study of the properties and transformations of organic compounds. This chapter deals with only a small part of the organic compounds that are important in technology.
Features of organic compounds
Organic compounds are very numerous and diverse, their number exceeds 4 million. The diversity of organic compounds is largely due to the ability of carbon atoms to form covalent bonds with each other. Due to the high strength of carbon-carbon bonds, chains are formed consisting of a large number of carbon atoms. Chains can be both open and closed (cycles). Carbon interacts with many other atoms. With hydrogen, carbon forms compounds called hydrocarbons. The diversity of organic compounds is also due to the phenomenon isomerism , which consists in the existence of substances of the same composition and molecular weight, but different in structure and spatial arrangement of atoms.
The features of organic compounds can also include the existence homologous series, in which each subsequent term can be derived from the previous one by adding one group of atoms defined for a given series. For example, in the homologous series of saturated hydrocarbons, such a group is CH2. The homologous series is characterized general formula, for example, C n H 2n+2 for saturated hydrocarbons. At the same time, there is a regular change in the physical properties of the elements as the number of groups increases.
Most organic compounds are characterized by a relatively low rate of chemical interactions under normal conditions. This is due to the high strength of the covalent bond carbon - carbon and carbon with other atoms and the relatively small difference in the bond energy of carbon with different atoms:
Communication with - H C-C C-Cl C-N C-S
Bond energy, kJ ………………………. 415 356 327 293 259
Electronegativity difference ……… 0.4 0.0 0.5 0.5 0.0
In a series of electronegativity values, carbon occupies an intermediate position between typical oxidizing and reducing agents, so the difference in the electronegativity of carbon with many other atoms is relatively small. Because of this, chemical bonds in organic compounds, as a rule, have low polarity. Most organic compounds are not capable of electrolytic dissociation.
The melting point of most organic compounds is relatively low (up to 100 - 200). At high temperatures, they burn in air mainly to carbon monoxide and water vapor.
17.1.2 The theory of the chemical structure of organic compounds by A.M. Butlerov In 1861, A.M. Butlerov formulated the main provisions of the theory of chemical structure.
1. The atoms in an organic molecule are interconnected in a certain order in accordance with their valency, which determines the chemical structure of the molecules.
2. Molecules with the same composition may have a different chemical structure and, accordingly, have different properties. Such molecules are called isomers. For a given empirical formula, a certain number of theoretically possible isomers can be derived.
3. Atoms in a molecule have mutual influence on each other, i.e. the properties of an atom may change depending on the nature of the other atoms of the compound. It should be noted that not only bound atoms experience mutual influence, but also those that are not directly bound to each other.
Organic and inorganic compounds.
Organic compounds, organic substances - class chemical compounds containing carbon.
The exceptions are some of the simplest carbon compounds (for example, carbides, carbonates, carbon oxides, carbonic acid, cyanides). These compounds are considered inorganic.
Organic compounds got their name due to the fact that in nature they are found almost exclusively in the organisms of animals and plants, they take part in life processes, or they are products of vital activity or decay of organisms.
Unlike organic compounds, substances such as sand, clay, various minerals, water, carbon oxides, carbonic acid and its salts, and other substances related to "inanimate nature" are called inorganic or mineral substances.
As carbon, being a part of all organic substances, is the most important element of the animal and plant kingdoms, so silicon is the main element of the kingdom of minerals and rocks.
History of discoveries of organic compounds.
For a long time it was believed that carbon-containing substances formed in organisms, in principle, cannot be obtained by synthesis from inorganic compounds.
The formation of organic substances was attributed to the influence of a special, inaccessible to knowledge "life force", acting only in living organisms, and causing the specificity of organic substances.
This doctrine was called vitalism (from the Latin vis vitalis - life force).
The concept of the vitalists was most fully formulated by one of the most respected chemists of the first half of XIX century by the Swedish scientist Berzelius.
In 1824, the German physicist Wöhler, a student of Berzelius, was the first to obtain oxalic acid (COOH)2 from the inorganic substance cyanogen (CN)2 by heating it with water, an organic compound that had until then been extracted only from plants.
In 1828, Wöhler carried out the first synthesis of a substance of animal origin: by heating the inorganic compound of ammonium cyanate NH4CNO, he obtained urea (urea) (NH2)2CO. Up to this point, carbamide has been isolated from urine only.
Syntheses of other organic substances were soon carried out in laboratory conditions:
In 1845 in Germany, G. Kolbe synthesized acetic acid,
In 1854 in France, M. Berthelot synthetically obtained fat,
· In 1861 in Russia A.M. Butlerov carried out the synthesis of a sugary substance.
Currently, many organic compounds are obtained by synthesis. Moreover, it turned out that many organic substances are much easier and cheaper to obtain synthetically than to isolate from natural products.
The greatest success of chemistry in the 50-60s of the XX century was the first synthesis of simple proteins - the hormone insulin and the enzyme ribonuclease.
Thus, the possibility of synthetic production of even proteins, the most complex organic substances that are indispensable participants in life processes, has been proven.
Structural features of organic compounds.
Organic compounds have an important feature. It consists in the fact that carbon atoms have a unique ability to form long chains and attach many other atoms to themselves, for example, atoms of hydrogen, oxygen, nitrogen, sulfur, phosphorus.
Moreover, the molecules formed in this way are quite stable, while molecules with a similar chain-like accumulation of atoms of other elements in the vast majority of cases are very fragile.
For example, for oxygen, the maximum known chain length is two atoms, and the compounds containing it (hydrogen peroxide and its derivatives) are unstable.
Long chains of carbon atoms are the reason for the huge variety of organic compounds. For this reason, there are innumerable combinations of combinations of atoms that form the molecules of such compounds.
So the total number of known inorganic compounds today is several tens of thousands, and the number of organic compounds has already exceeded two million.
This circumstance makes it necessary to separate the detailed study of the chemistry of carbon into an independent field called organic chemistry.
Structural isomerism and structural formulas
Structural isomerism
The phenomenon of isomerism is common among organic compounds. There are many carbon compounds that have the same qualitative and quantitative composition and the same molecular weight, but completely different physical and often chemical properties.
For example, the composition C 2 H 6 O and, accordingly, two different isomeric organic substances have a molecular weight of 46.07:
1. ethanol - a liquid boiling at 78.4 C, miscible with water in any ratio and
2. dimethyl ether- a gas that is almost insoluble in water and differs significantly from ethyl alcohol in chemical properties.
Another example:
Formula C 2 H 4 O 2 can correspond to both acetic acid and glycolaldehyde.
Structural formulas
In order to avoid confusion, structural formulas are used to write the formulas of such substances.
Structural formula- is a variety chemical formula, which graphically describes the arrangement and bond order of atoms in a compound, expressed in a plane. Links in structural formulas ax are denoted by valence lines.
So, the structural formulas of the substances given as examples above will look like this:
Such a graphic representation of structural formulas is rather complicated and time consuming. Often the formulas of organic compounds are written in such a way that they give an idea of the length of the hydrocarbon chain and the functional groups present in the molecule.
The allocation of functional groups is important because it is they that largely determine Chemical properties compounds So, the formulas of the above substances can be written as follows:
1. CH 3 - O - CH 3- dimethyl ether,
2. C 2 H 5 - OH- ethanol ( HE- hydroxyl group)
3. CH 3 - COOH- acetic acid ( UNSD- carboxyl group)
4. CH 2 OH - CHO– glycolaldehyde ( AtoN- aldehyde group).
External electron shell A carbon atom has four electrons, with which it forms four covalent bonds with other atoms. With the help of simple (single) covalent bonds a carbon atom can attach four other atoms to itself.
But atoms can be bound not only by a single, but also by a double or triple covalent bond.
In structural formulas, such bonds are indicated by double or triple dashes. Examples of compounds with double and triple bonds are ethylene C 2 H 4 and acetylene C 2 H 2:
Carbon. Structural features. Properties.
The structure of carbon
Carbon is the sixth element periodic system Mendeleev. Its atomic weight is 12.
Carbon is in the second period of the Mendeleev system and in the fourth group of this system.
The period number tells us that the six electrons of carbon are in two energy levels.
And the fourth group number says that carbon has four electrons at the external energy level. Two of them are paired s-electrons, and the other two are not paired R-electrons.
The structure of the outer electron layer of the carbon atom can be expressed by the following schemes:
Each cell in these diagrams means a separate electron orbital, the arrow is an electron in an orbital. Two arrows inside one cell are two electrons that are in the same orbit, but have opposite spins.
When an atom is excited (when energy is imparted to it), one of the paired S-electrons occupies R-orbital.
An excited carbon atom can participate in the formation of four covalent bonds. Therefore, in the vast majority of its compounds, carbon exhibits a valency of four.
So, the simplest organic compound hydrocarbon methane has the composition CH 4. Its structure can be expressed by structural or electronic formulas:
Electronic formula shows that the carbon atom in the methane molecule has a stable eight-electron outer shell, and hydrogen atoms have a stable two-electron shell.
All four covalent bonds of carbon in methane (and in other similar compounds) are equivalent and symmetrically directed in space. The carbon atom is, as it were, in the center of the tetrahedron (a regular quadrangular pyramid), and the four atoms connected to it (in the case of methane, four hydrogen atoms) are at the vertices of the tetrahedron.
Organic chemistry - branch of chemistry that studies carbon compounds, their structure, properties , methods of synthesis, as well as the laws of their transformations. Organic compounds are called carbon compounds with other elements (mainly with H, N, O, S, P, Si, Ge, etc.).
The unique ability of carbon atoms to bind to each other, forming chains of various lengths, cyclic structures of various sizes, framework compounds, compounds with many elements, different in composition and structure, determines the diversity of organic compounds. To date, the number of known organic compounds is much more than 10 million and increases every year by 250-300 thousand. The world around us is built mainly from organic compounds, these include: food, clothing, fuel, dyes, medicines, detergents, materials for various branches of technology and National economy. Organic compounds play a key role in the existence of living organisms.
At the junction of organic chemistry with inorganic chemistry, biochemistry and medicine, the chemistry of organometallic and elemental compounds, bioorganic and medical chemistry, and the chemistry of macromolecular compounds arose.
The main method of organic chemistry is synthesis. Organic chemistry studies not only compounds derived from plant and animal sources (natural substances), but mainly compounds created artificially through laboratory and industrial synthesis.
History of the development of organic chemistry
Methods for obtaining various organic substances have been known since antiquity. So, the Egyptians and Romans used dyes of plant origin - indigo and alizarin. Many nations owned the secrets of the production of alcoholic beverages and vinegar from sugar and starch-containing raw materials.
During the Middle Ages, practically nothing was added to this knowledge, some progress began only in the 16-17 centuries (the period of iatrochemistry), when new organic compounds were isolated by distillation of plant products. In 1769-1785 K.V. Scheele isolated several organic acids: malic, tartaric, citric, gallic, lactic and oxalic. In 1773 G.F. Ruel isolated urea from human urine. Substances isolated from animal and vegetable raw materials had much in common, but differed from inorganic compounds. This is how the term "Organic Chemistry" arose - a branch of chemistry that studies substances isolated from organisms (definition Y.Ya. Berzelius, 1807). At the same time, it was believed that these substances can only be obtained in living organisms due to the "life force".
It is generally accepted that organic chemistry as a science appeared in 1828, when F. Wöhler first received an organic substance - urea - as a result of evaporation of an aqueous solution of an inorganic substance - ammonium cyanate (NH 4 OCN). Further experimental work demonstrated indisputable arguments of the inconsistency of the theory of "life force". For example, A. Kolbe synthesized acetic acid, M. Berthelot received methane from H 2 S and CS 2, and A.M. Butlerov synthesized saccharides from formalin.
In the middle of the 19th century the rapid development of synthetic organic chemistry continues, the first industrial production of organic substances is created ( A. Hoffman, W. Perkin Sr.- synthetic dyes, fuchsin, cyanine and aza dyes). Open N.N. Zinin(1842) of the method for the synthesis of aniline served as the basis for the creation of the aniline-dye industry. In the laboratory A. Bayer natural dyes were synthesized - indigo, alizarin, indigo, xanthene and anthraquinone.
An important stage in the development of theoretical organic chemistry was the development F. Kekule theory of valency in 1857, as well as the classical theory of chemical structure A.M. Butlerov in 1861, according to which atoms in molecules are connected in accordance with their valency, chemical and physical properties compounds are determined by the nature and number of atoms included in them, as well as the type of bonds and the mutual influence of directly unbound atoms. In 1865 F. Kekule proposed the structural formula of benzene, which became one of the most important discoveries in organic chemistry. V.V. Markovnikov and A.M. Zaitsev formulated a number of rules that for the first time connected the direction of organic reactions with the structure of the substances entering into them. In 1875 Van't Hoff and Le Bel proposed a tetrahedral model of the carbon atom, according to which the valences of carbon are directed to the vertices of the tetrahedron, in the center of which the carbon atom is located. Based on this model, combined with experimental studies I. Wislicenus(! 873), which showed the identity of the structural formulas of (+)-lactic acid (from sour milk) and (±)-lactic acid, stereochemistry arose - the science of the three-dimensional orientation of atoms in molecules, which predicted in the case of the presence of 4 different substituents at carbon atom (chiral structures) the possibility of the existence of space-mirror isomers (antipodes or enantiomers).
In 1917 Lewis proposed to consider chemical bond using electronic pairs.
In 1931 Hückel applied quantum theory to explain the properties of non-benzenoid aromatic systems, which founded a new direction in organic chemistry - quantum chemistry. This served as an impetus for the further intensive development of quantum chemical methods, in particular the method of molecular orbitals. The stage of penetration of orbital representations into organic chemistry was opened by the theory of resonance L. Pauling(1931-1933) and further work K. Fukui, R. Woodward and R. Hoffmann on the role of frontier orbitals in determining the direction of chemical reactions.
Mid 20th century characterized by a particularly rapid development of organic synthesis. This was determined by the discovery of fundamental processes, such as the production of olefins using ylides ( G. Wittig, 1954), diene synthesis ( O. Diels and C. Alder, 1928), hydroboration of unsaturated compounds ( G. Brown, 1959), nucleotide synthesis and gene synthesis ( A. Todd, H. Qur'an). Advances in the chemistry of organometallic compounds are largely due to the work A.N. Nesmeyanov and G.A. Razuvaeva. In 1951, the synthesis of ferrocene was carried out, the establishment of the "sandwich" structure of which R. Woodward and J. Wilkinson marked the beginning of the chemistry of metallocene compounds and, in general, the organic chemistry of transition metals.
In 20-30 years. A.E. Arbuzov creates the foundations of the chemistry of organophosphorus compounds, which subsequently led to the discovery of new types of physiologically active compounds, complexons, etc.
In the 60-80s. Ch. Pedersen, D. Cram and J.M. Linen develop the chemistry of crown ethers, cryptands and other related structures capable of forming strong molecular complexes, and thus approach the most important problem of "molecular recognition".
Modern organic chemistry continues its rapid development. New reagents, fundamentally new synthetic methods and techniques, new catalysts are introduced into the practice of organic synthesis, previously unknown organic structures. The search for organic new biologically active compounds is constantly being conducted. Many more problems of organic chemistry are waiting to be solved, for example, a detailed establishment of the structure-property relationship (including biological activity), the establishment of the structure and stereodirected synthesis of complex natural compounds, the development of new regio- and stereoselective synthetic methods, the search for new universal reagents and catalysts .
The interest of the world community in the development of organic chemistry was vividly demonstrated by the presentation Nobel Prize in Chemistry 2010 R. Heku, A. Suzuki and E. Negishi for his work on the use of palladium catalysts in organic synthesis for the formation of carbon-carbon bonds.
Classification of organic compounds
The classification is based on the structure of organic compounds. The basis of the description of the structure is the structural formula.
Main classes of organic compounds
Hydrocarbons - compounds consisting only of carbon and hydrogen. They, in turn, are divided into:
Saturated- contain only single (σ-bonds) and do not contain multiple bonds;
Unsaturated- contain at least one double (π-bond) and/or triple bond;
open chain(alicyclic);
closed circuit(cyclic) - contain a cycle
These include alkanes, alkenes, alkynes, dienes, cycloalkanes, arenes
Compounds with heteroatoms in functional groups- compounds in which the carbon radical R is associated with a functional group. Such compounds are classified according to the nature of the functional group:
Alcohol, phenols(contain hydroxyl group OH)
Ethers(contain grouping R-O-R or R-O-R
Carbonyl compounds(contain the group RR "C = O), these include aldehydes, ketones, quinones.
Compounds containing a carboxyl group(COOH or COOR), these include carboxylic acids, esters
Element- and organometallic compounds
Heterocyclic compounds - contain heteroatoms in the ring. They differ in the nature of the cycle (saturated, aromatic), in the number of atoms in the cycle (three-, four-, five-, six-membered cycles, etc.), in the nature of the heteroatom, in the number of heteroatoms in the cycle. It defines huge variety known and annually synthesized compounds of this class. The chemistry of heterocycles is one of the most exciting and important areas of organic chemistry. Suffice it to say that more than 60% of drugs of synthetic and natural origin belong to various classes of heterocyclic compounds.
Natural compounds - compounds, as a rule, of a rather complex structure, often belonging to several classes of organic compounds at once. Among them are: amino acids, proteins, carbohydrates, alkaloids, terpenes, etc.
Polymers- substances with a very large molecular weight, consisting of periodically repeating fragments - monomers.
The structure of organic compounds
Organic molecules are mainly formed by covalent non-polar C-C bonds, or covalent polar bonds C-O type, C-N, C-Hal. Polarity is explained by the shift of the electron density towards the more electronegative atom. To describe the structure of organic compounds, chemists use the language of structural formulas of molecules, in which the bonds between individual atoms are indicated by one (single, or single bond), two (double) or three (triple) valence strokes. The concept of a valency stroke, which has not lost its meaning to this day, was introduced into organic chemistry A. Cooper in 1858
Very important for understanding the structure of organic compounds is the concept of hybridization of carbon atoms. The carbon atom in the ground state has an electronic configuration 1s 2 2s 2 2p 2, on the basis of which it is impossible to explain the valency 4 inherent in carbon in its compounds and the existence of 4 identical bonds in alkanes directed to the vertices of the tetrahedron. In the framework of the method of valence bonds, this contradiction is resolved by introducing the concept of hybridization. When excited, s→p electron transition and the subsequent, so-called, sp- hybridization, with the energy of the hybridized orbitals being intermediate between the energies s- and p-orbitals. When bonds are formed in alkanes, three R-electron interact with one s-electron ( sp 3 hybridization) and 4 identical orbitals arise, located at tetrahedral angles (109 about 28 ") to each other. Carbon atoms in alkenes are in sp 2-hybrid state: each carbon atom has three identical orbitals lying in the same plane at an angle of 120 about to each other ( sp 2 orbitals), and the fourth ( R-orbital) is perpendicular to this plane. Overlapping R-orbitals of two carbon atoms forms a double (π) bond. The carbon atoms that carry the triple bond are in sp- hybrid state.
Features of organic reactions
AT inorganic reactions usually ions are involved, such reactions are fast and complete at room temperature. In organic reactions, covalent bonds are often broken with the formation of new ones. As a rule, these processes require special conditions: a certain temperature, reaction time, certain solvents, and often the presence of a catalyst. Usually, not one, but several reactions take place at once. Therefore, when depicting organic reactions, not equations are used, but schemes without calculating stoichiometry. The yields of target substances in organic reactions often do not exceed 50%, and their isolation from the reaction mixture and purification require specific methods and techniques. To purify solids, as a rule, recrystallization from specially selected solvents is used. Liquid substances are purified by distillation at atmospheric pressure or under vacuum (depending on the boiling point). To control the progress of reactions, separate complex reaction mixtures, various types of chromatography are used [thin-layer chromatography (TLC), preparative high-performance liquid chromatography (HPLC), etc.].
Reactions can proceed very complicatedly and in several stages. Radicals R·, carbocations R + , carbanions R - , carbenes:СХ 2 , radical cations, radical anions and other active and unstable particles, usually living for a fraction of a second, can appear as intermediate compounds. A detailed description of all the transformations that occur at the molecular level during a reaction is called reaction mechanism. According to the nature of the gap and the formation of bonds, radical (homolytic) and ionic (heterolytic) processes are distinguished. According to the types of transformations, chain radical reactions, nucleophilic (aliphatic and aromatic) substitution reactions, elimination reactions, electrophilic addition, electrophilic substitution, condensation, cyclization, rearrangement processes, etc. are distinguished. Reactions are also classified according to the methods of their initiation (excitation ), their kinetic order (monomolecular, bimolecular, etc.).
Determination of the structure of organic compounds
Throughout the existence of organic chemistry as a science, the most important task has been to determine the structure of organic compounds. This means to find out which atoms are part of the structure, in what order and how these atoms are interconnected and how they are located in space.
There are several methods for solving these problems.
- elemental analysis consists in the fact that the substance is decomposed into simpler molecules, by the number of which it is possible to determine the number of atoms that make up the compound. This method does not make it possible to establish the order of bonds between atoms. Often used only to confirm the proposed structure.
- Infrared spectroscopy (IR spectroscopy) and Raman spectroscopy (Raman spectroscopy). The method is based on the fact that the substance interacts with electromagnetic radiation (light) of the infrared range (absorption is observed in IR spectroscopy, and radiation scattering is observed in Raman spectroscopy). This light, when absorbed, excites the vibrational and rotational levels of the molecules. The reference data are the number, frequency and intensity of vibrations of the molecule associated with a change in the dipole moment (IC) or polarizability (CR). The method allows you to establish the presence of functional groups, and is also often used to confirm the identity of a substance with some already known substance by comparing their spectra.
- Mass spectrometry. A substance under certain conditions (electron impact, chemical ionization, etc.) turns into ions without loss of atoms (molecular ions) and with loss (fragmentation, fragmentary ions). The method allows you to determine the molecular weight of a substance, its isotopic composition, and sometimes the presence of functional groups. The nature of the fragmentation makes it possible to draw some conclusions about the structural features and to recreate the structure of the compound under study.
- Nuclear magnetic resonance (NMR) method based on the interaction of nuclei with their own magnetic moment(spin) and placed in an external constant magnetic field (spin reorientation), with variable electromagnetic radiation of the radio frequency range. NMR is one of the most important and informative methods for determining the chemical structure. The method is also used to study the spatial structure and dynamics of molecules. Depending on the nuclei interacting with radiation, there are, for example, the method of proton resonance PMR, NMR 1 H), which allows you to determine the position of hydrogen atoms in a molecule. The 19 F NMR method makes it possible to determine the presence and position of fluorine atoms. The 31 P NMR method provides information on the presence, valence state, and position of phosphorus atoms in a molecule. The 13C NMR method makes it possible to determine the number and types of carbon atoms; it is used to study the carbon skeleton of a molecule. Unlike the first three, the last method uses a minor isotope of the element, since the nucleus of the main 12 C isotope has zero spin and cannot be observed by NMR.
- Method of ultraviolet spectroscopy (UV spectroscopy) or electronic transition spectroscopy. The method is based on the absorption of electromagnetic radiation in the ultraviolet and visible regions of the spectrum during the transition of electrons in a molecule from the upper filled energy levels to vacant ones (excitation of the molecule). Most often used to determine the presence and characteristics of conjugate π-systems.
- Methods of analytical chemistry make it possible to determine the presence of certain functional groups by specific chemical (qualitative) reactions, the fact of which can be fixed visually (for example, the appearance or change in color) or using other methods. In addition to chemical methods of analysis in organic chemistry, instrumental analytical methods, such as chromatography (thin layer, gas, liquid). A place of honor among them is occupied by chromatography-mass spectrometry, which makes it possible not only to assess the degree of purity of the obtained compounds, but also to obtain mass spectral information about the components of complex mixtures.
- Methods for studying the stereochemistry of organic compounds. From the beginning of the 80s. the expediency of developing a new direction in pharmacology and pharmacy associated with the creation of enantiomerically pure drugs with an optimal ratio of therapeutic efficacy and safety has become obvious. Currently, approximately 15% of all synthesized pharmaceuticals are represented by pure enantiomers. This trend was reflected in the appearance in the scientific literature recent years term chiral switch, which in Russian translation means “switching to chiral molecules”. Concerning special meaning in organic chemistry, they acquire methods for establishing the absolute configuration of chiral organic molecules and determining their optical purity. The main method for determining the absolute configuration should be considered X-ray diffraction analysis (XRD), and optical purity - chromatography on columns with a stationary chiral phase and the NMR method using special additional chiral reagents.
The connection of organic chemistry with the chemical industry
The main method of organic chemistry - synthesis - closely links organic chemistry with the chemical industry. Based on the methods and developments of synthetic organic chemistry, small-tonnage (fine) organic synthesis arose, including the production of drugs, vitamins, enzymes, pheromones, liquid crystals, organic semiconductors, solar cells, etc. The development of large-tonnage (basic) organic synthesis is also based on the achievements of organic chemistry. The main organic synthesis includes the production of artificial fibers, plastics, processing of oil, gas and coal raw materials.
Recommended reading
- G.V. Bykov, History of organic chemistry, M.: Mir, 1976 (http://gen.lib/rus.ec/get?md5=29a9a3f2bdc78b44ad0bad2d9ab87b87)
- J. March, Organic chemistry: reactions, mechanisms and structure, in 4 volumes, M.: Mir, 1987
- F. Carey, R. Sandberg, Advanced Course in Organic Chemistry, in 2 volumes, M.: Chemistry, 1981
- O.A. Reutov, A.L. Kurtz, K.P. Butin, Organic chemistry, in 4 parts, M .: "Binom, Knowledge Laboratory", 1999-2004. (http://edu.prometey.org./library/author/7883.html)
- Chemical Encyclopedia, ed. Knunyants, M.: "Great Russian Encyclopedia", 1992.
LIPIDS_ chemically, most lipids are esters of higher carboxylic acids and a number of alcohols. The most famous among them are fats. Each fat molecule is formed by a molecule of the trihydric alcohol glycerol and ester bonds of three molecules of higher carboxylic acids attached to it. According to the accepted nomenclature, fats are called triacylglycerols.
FUNCTIONS
1) structural,
2) protective,
3) thermo- waterproofing,
4) synthetic (component of many hormones),
5) energy,
6) storage function.
Lipids form a thermally insulating layer in the body, are part of the secretions of the sebaceous glands.
PROTEINS_Protein molecules are large, so they are called macromolecules. In addition to carbon, oxygen, hydrogen, and nitrogen, proteins can contain sulfur, phosphorus, and iron. Proteins differ from each other in number (from one hundred to several thousand), composition and sequence of monomers. The monomers of proteins are amino acids. The uniqueness of a protein is determined by the sequence of connecting certain amino acids. Protein molecules can form a primary, secondary, tertiary and quaternary structure.
Proteins perform many functions in the cell: enzymatic, transport, protective, etc.
Nucleic acids
/ \
RNA DNA
Nucleic acid molecules are long polymeric chains whose monomers are nucleotides. Each nucleotide consists of a nitrogenous base, a carbohydrate, phosphoric acid residues (one of three).
FUNCTIONS
1) catalytic
2) building
3) transport
4) protective
5) motor
6) energy
7) hormonal
8) receptor
CARBOHYDRATES_substances with the general formula Cn(H2O)m, where n and m can have different values. They are the primary products of photosynthesis and the initial products of the biosynthesis of other organic substances in plants. Carbohydrates come in 3 varieties, they are biopolymers, there are homopolysaccharides (starch, chitin, glycogen, cellulose), heteropolysaccharides (pectin, murein, heparin)
FUNCTIONS:
1. energy (with the breakdown of 1 g of carbohydrate = 17.6 kJ of energy)
2. structural (shells of plant cells)
3. storage (reserve nutrients - starch, glycogen, cellulose) (organic acids, alcohols, amino acids, etc.), and are also found in the cells of all other organisms.
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