Electrons that form a spherical orbital are called. Atomic orbitals

The wave function (7), which describes the state of the electron, is called atomic orbital(AO).

Quantum numbers. In quantum mechanics, each AO is defined by three quantum numbers.

Principal quantum number n. Can take integer values ​​from 1 to ∞. The main quantum number determines:

energy level number;

energy range of electrons located at this level;

orbital sizes;

the number of sublevels of a given energy level (the first level consists of one sublevel, the second - of two, the third - of three, etc.);

In the Periodic Table of Elements maximum value The principal quantum number corresponds to the period number.

Orbital quantum number l.Determines the orbital angular momentum (momentum) of the electron, exact value its energy and shape of orbitals. Can take values ​​0, 1, 2, 3, …, ( n-1).

Atomic orbital– geometric image of the one-electron wave function ψ, which represents the region of the most probable presence of an electron in an atom. It limits the region of space in which the probability of finding an electron has a certain value (90 ... 99%). Sometimes an orbital is called the boundary surface of this region, and in drawings, as a rule, a cross section of this region is depicted by a plane passing through the origin of coordinates and lying in the plane of the drawing. The center of the atomic nucleus is placed at the origin. The concept of “orbital,” unlike “orbit,” does not imply knowledge of the exact coordinates of the electron. The orbital quantum number determines the shape of the atomic orbital. At l=0 is a sphere, with l=1 – volume eight (dumbbell), with l=2 – four-petal rosette.

Each value of the principal quantum number corresponds to n orbital quantum number values l(Table 1). For example, if n=1, then l takes only one value ( l=0), n=2 – two values: 0 and 1, etc. Each numerical value l corresponds to a certain geometric shape orbitals and is assigned a letter designation. The first four letters of the designation are historical origin and related to character spectral lines. s, p, d, f– first letters English words, used to name the spectral lines: sharp (sharp), principal (main), diffuse (diffuse), fundamental (main). The designations of other orbitals are given in alphabetical order: g, h, …

Table 1

Values ​​of the principal and orbital quantum numbers

The designation of any sublevel is determined by two quantum numbers - the main one (when writing, the numerical value is indicated) and orbital (when writing, the letter designation is indicated; orbital ()the numerical value is indicated by two quantum numbers - the main one). For example, the energy sublevel for which n=2 and l=1, should be designated as follows: 2p-sublevel. All orbitals with the same value l have the same geometric formula and depending on the values ​​of the principal quantum number they differ in size. For example, all orbitals for which l=0 (s-orbitals) are spherically symmetrical and differ in size depending on the value of the principal quantum number. The higher the value n, the larger the size of the orbitals.

Magnetic quantum number m l.Determines the possible values ​​of the projection of the orbital angular momentum of an electron onto a fixed direction in space (for example, onto the axis z). It accepts negative and positive values l, including zero. Total number of values ​​is 2 l+1:

The interaction depends on the value of the magnetic quantum number magnetic field created by an electron with an external magnetic field. If there is no external magnetic field, then the energy of the electron in the atom does not depend on m l. In this case, electrons with the same values n And l, nose different meanings m l have the same energy. If there is an external magnetic field, the energy of electrons with different m l varies.

IN general case magnetic quantum number characterizes the orientation of the AO in space relative to external force. The magnetic quantum number determines the orientation of the orbital angular momentum relative to some fixed direction.

Total number possible valuesm l corresponds to the number of ways to arrange the orbitals of a given sublevel in space, that is total number orbitals at this sublevel (Table 2).

table 2

Number of orbitals per sublevel

Orbital quantum number l=0 corresponds to the only value of the magnetic quantum number m l=0. These values l And m l characterize everything s-orbitals that have the shape of a sphere. Since in this case the magnetic quantum number takes only one value, each s-sublevel consists of only one orbital. Let's consider any R-sublevel. At l=1 orbitals have the shape of dumbbells (volume eights), the magnetic quantum number takes following values: m l= -1, 0, +1. Hence, R-the sublevel consists of three AOs, which are located along the coordinate axes; they are designated p x, p y, p z accordingly (Fig. 1).

Rice. 1. Spatial form of s- and p-atomic orbitals.

For d-sublevel l=2, m l= -2, -1, 0, +1, +2 (5 values ​​in total), and any d-sublevel consists of five atomic orbitals, which are located in a certain way in space (Fig. 2), and are designated respectively.

Rice. 2. Spatial form of d-atomic orbitals.

Four out of five d- orbitals have the shape of four-lobed rosettes, each of which is formed by two dumbbells, the fifth AO is a dumbbell with a torus in the equatorial plane (-orbital) and is located along the axis z. The orbital lobes are located along the x and y axes. The orbital lobes are located symmetrically between the corresponding axes.

The fourth energy level consists of four sublevels - s, p, d And f. The first three of them are similar to those described above, and the fourth f-the sublevel consists of seven AOs, the spatial form of which is quite complex and this section not considered.

S. Goudsmit and J. Uhlenbeck to describe some subtle effects in the spectrum of the hydrogen atom in 1925, they hypothesized the presence of the electron’s own angular momentum, which they called spin. Spin cannot be expressed in terms of coordinates and momenta; it has no analogue in classical mechanics. Spin number s electron takes only one value, equal Projection spin vector in a certain direction external field(for example, on an axis z) is determined spin quantum numberm S , which can take two values: m S =

The concept of “spin” was introduced to characterize a specific quantum properties electron. Spin is a manifestation relativistic effects at the microscopic level.

The electron has four degrees of freedom. The spin quantum number takes only discrete values: Thus, the state of an electron in an atom is determined by a set of values ​​of four quantum numbers: n, l, m l, m S.

Designation and structure of electronic energy levels. Let's define some terms that are used to clarify physical meaning quantum numbers. A group of orbitals having the same orbital quantum number forms energy sublevel. The set of all orbitals with the same value of the principal quantum number forms energy level.

The structure of atomic electronic levels can be depicted in two ways: in the form of electronic formulas and electron diffraction diagrams. When writing electronic formulas, two quantum numbers n and l are used: the first level is 1 s; second – 2 s, 2p; third – 3 s, 3p, 3d; fourth – 4 s, 4p, 4d, 4f etc. (Table 3).

Table 3

Structure of electronic energy levels of an atom

The structure of electronic levels is more fully described using three quantum numbers: n, l, m l. Each JSC is conventionally depicted in the form of quantum cells, next to which a level number and a sublevel symbol are placed.

Orbitals exist regardless of whether an electron is present in them (occupied orbitals) or absent (vacant orbitals). The atom of each element, starting with hydrogen and ending with the last element obtained today, has full set all orbitals at all electronic levels. Their filling with electrons occurs as the serial number, that is, the charge of the nucleus.

s-Orbitals, as shown above, have a spherical shape and, therefore, the same electron density in the direction of each three-dimensional coordinate axis:

At the first electronic level of each atom there is only one s- orbital. Starting from the second electronic level in addition to s- three orbitals also appear R-orbitals. They are shaped like three-dimensional eights, this is what the area of ​​the most likely location looks like R-electron in the region of the atomic nucleus. Each R-the orbital is located along one of three mutually perpendicular axes, in accordance with this in the name R-orbitals indicate, using the corresponding index, the axis along which its maximum electron density is located:

IN modern chemistry orbital is a defining concept that allows us to consider the processes of formation chemical bonds and analyze their properties, while focusing on the orbitals of those electrons that participate in the formation of chemical bonds, that is, valence electrons, usually these are electrons of the last level.

The carbon atom in the initial state has two electrons in the second (last) electronic level. s-orbitals (marked in blue) and one electron in two R-orbitals (marked in red and yellow), third orbital – p z-vacant:

Hybridization.

In the case when a carbon atom participates in the formation of saturated compounds (not containing multiple bonds), one s- orbital and three R-orbitals combine to form new orbitals that are hybrids of the original orbitals (the process is called hybridization). The number of hybrid orbitals is always equal to the number of original ones, in in this case, four. The resulting hybrid orbitals are identical in shape and outwardly resemble asymmetrical three-dimensional figure eights:

The whole structure appears to be inscribed in regular tetrahedron- a prism assembled from regular triangles. In this case, the hybrid orbitals are located along the axes of such a tetrahedron, the angle between any two axes is 109°. Carbon's four valence electrons are located in these hybrid orbitals:

Participation of orbitals in the formation of simple chemical bonds.

The properties of electrons located in four identical orbitals are equivalent; accordingly, the chemical bonds formed with the participation of these electrons when interacting with atoms of the same type will be equivalent.

The interaction of a carbon atom with four hydrogen atoms is accompanied by the mutual overlap of elongated hybrid orbitals of carbon with spherical orbitals of hydrogen. Each orbital contains one electron; as a result of overlap, each pair of electrons begins to move along the united molecular orbital.

Hybridization only leads to a change in the shape of the orbitals within one atom, and the overlap of the orbitals of two atoms (hybrid or ordinary) leads to the formation of a chemical bond between them. In this case ( cm. Figure below) the maximum electron density is located along the line connecting two atoms. Such a connection is called an s-connection.

IN traditional spelling The structures of the resulting methane use a valence bar symbol instead of overlapping orbitals. For a three-dimensional image of a structure, the valence directed from the drawing plane to the viewer is shown in the form of a solid wedge-shaped line, and the valence extending beyond the drawing plane is shown in the form of a dashed wedge-shaped line:

Thus, the structure of the methane molecule is determined by the geometry of the hybrid orbitals of carbon:

The formation of an ethane molecule is similar to the process shown above, the difference is that when the hybrid orbitals of two carbon atoms overlap, S-S education– connections:

The geometry of the ethane molecule resembles methane, bond angles are 109°, which is determined by the spatial arrangement of carbon hybrid orbitals:

Participation of orbitals in the formation of multiple chemical bonds.

The ethylene molecule is also formed with the participation of hybrid orbitals, but only one is involved in hybridization s-orbital and only two R-orbitals ( p x And RU), third orbital – p z, directed along the axis z, does not participate in the formation of hybrids. From the initial three orbitals, three hybrid orbitals arise, which are located in the same plane, forming a three-rayed star, the angles between the axes are 120°:

Two carbon atoms attach four hydrogen atoms and also connect to each other, forming a C-C s-bond:

Two orbitals p z, which did not participate in hybridization, overlap each other, their geometry is such that the overlap does not occur along the line S-S connections, and above and below it. As a result, two regions with increased electron density are formed, where two electrons (marked in blue and red) are located, participating in the formation of this bond. Thus, one molecular orbital is formed, consisting of two regions separated in space. A bond in which the maximum electron density is located outside the line connecting two atoms is called a p-bond:

Second valence feature in the notation double bond, widely used to depict unsaturated compounds for centuries, in modern understanding implies the presence of two regions with increased electron density located along different sides communication lines S-S.

The structure of the ethylene molecule is determined by the geometry of hybrid orbitals, valence angle N-S-N– 120°:

During the formation of acetylene, one s-orbital and one p x-orbital (orbitals p y And p z, do not participate in the formation of hybrids). The two resulting hybrid orbitals are located on the same line, along the axis X:

The overlap of hybrid orbitals with each other and with the orbitals of hydrogen atoms leads to the formation of C-C and C-H s-bonds, represented by a simple valence line:

Two pairs of remaining orbitals p y And p z overlap. In the figure below, colored arrows show that, from purely spatial considerations, the most likely overlap of orbitals with the same indices x-x And ooh. As a result, two p-bonds are formed surrounding a simple s-bond C-C:

As a result, the acetylene molecule has a rod-shaped shape:

In benzene, the molecular backbone is assembled from carbon atoms having hybrid orbitals composed of one s- and two R-orbitals arranged in the shape of a three-rayed star (like ethylene), R-orbitals not involved in hybridization are shown semi-transparent:

Vacant orbitals, that is, those not containing electrons (), can also participate in the formation of chemical bonds.

High level orbitals.

Starting from the fourth electronic level, atoms have five d-orbitals, their filling with electrons occurs at transition elements, starting with scandium. Four d-orbitals have the shape of three-dimensional four-leaf clovers, sometimes called “clover leaves”, they differ only in orientation in space, the fifth d-orbital is a three-dimensional figure eight threaded into a ring:

d-Orbitals can form hybrids with s- And p- orbitals. Options d-orbitals are usually used in analyzing the structure and spectral properties in transition metal complexes.

Starting from the sixth electronic level, atoms have seven f-orbitals, their filling with electrons occurs in the atoms of lanthanides and actinides. f-The orbitals have a rather complex configuration; the figure below shows the shape of three of the seven such orbitals, which have same shape and oriented in space in different ways:

f-Orbitals are very rarely used when discussing the properties of various compounds, since the electrons located on them practically do not take part in chemical transformations.

Prospects.

At the eighth electronic level there are nine g-orbitals. Elements containing electrons in these orbitals should appear in the eighth period, while they are not available (element No. 118, the last element of the seventh period, is expected soon Periodic table, its synthesis is carried out at the Joint Institute for Nuclear Research in Dubna).

Form g-orbitals, calculated by quantum chemistry methods, are even more complex than those of f-orbitals, the region of the most probable location of the electron in this case looks very bizarre. Shown below appearance one of nine such orbitals:

In modern chemistry, concepts of atomic and molecular orbitals are widely used in describing the structure and reaction properties of compounds, also in analyzing the spectra of various molecules, and in some cases to predict the possibility of reactions occurring.

Mikhail Levitsky

The wave function is calculated by wave equation Schrödinger within the framework of the one-electron approximation (Hartree-Fock method) as wave function an electron located in a self-consistent field created by the nucleus of an atom with all other electrons of the atom.

E. Schrödinger himself considered an electron in an atom as a negatively charged cloud, the density of which is proportional to the square of the value of the wave function at the corresponding point of the atom. In this form, the concept of an electron cloud was also adopted in theoretical chemistry.

However, most physicists did not share the beliefs of E. Schrödinger - there was no evidence of the existence of the electron as a “negatively charged cloud”. Max Born substantiated the probabilistic interpretation of the square of the wave function. In 1950, E. Schrödinger, in the article “What is elementary particle? I am forced to agree with the arguments of M. Born, who was awarded Nobel Prize in physics with the wording “For basic research in area quantum mechanics, especially for the statistical interpretation of the wave function."

Quantum numbers and orbital nomenclature

Radial probability density distribution for atomic orbitals at different n And l.

• Principal quantum number n can take any positive integer value, starting from one ( n= 1,2,3, … ∞) and determines total energy electron in a given orbital (energy level):

• The orbital quantum number (also called the azimuthal or complementary quantum number) determines the angular momentum of the electron and can take integer values ​​from 0 to n - 1 (l = 0,1, …, n- 1). The angular momentum is given by the relation

The letter designations for atomic orbitals come from the description of spectral lines in atomic spectra: s (sharp) - a sharp series in atomic spectra, p (principal)- home, d (diffuse) - diffuse, f (fundamental) - fundamental.

• Magnetic quantum number m l determines the projection of the orbital angular momentum onto the direction of the magnetic field and can take integer values ​​in the range from - l before l, including 0 ( m l = -l … 0 … l):

In the literature, orbitals are denoted by a combination of quantum numbers, with the principal quantum number denoted by a number, the orbital quantum number by the corresponding letter (see table below) and the magnetic quantum number by a subscript expression showing the projection of the orbital onto the Cartesian axes x, y, z, For example 2p x, 3d xy, 4f z(x²-y²). For orbitals of the outer electron shell, that is, in the case of describing valence electrons, the main quantum number in the orbital notation is usually omitted.

Geometric representation

Geometric representation of an atomic orbital - a region of space bounded by a surface equal density(equidensity surface) probability or charge. The probability density on the boundary surface is chosen based on the problem being solved, but usually in such a way that the probability of finding an electron in limited area lay in the range of values ​​0.9-0.99.

Since the electron energy is determined Coulomb interaction and, therefore, the distance from the nucleus, then the principal quantum number n sets the size of the orbital.

The shape and symmetry of the orbital are determined by the orbital quantum numbers l And m: s-orbitals are spherically symmetrical, p, d And f-orbitals have more complex shape, determined by the angular parts of the wave function - angular functions. Angular functions Y lm (φ , θ) - native functions operator of squared angular momentum L², depending on quantum numbers l And m(see Spherical functions), are complex and describe in spherical coordinates(φ, θ) angular dependence of the probability of finding an electron in the central field of the atom. The linear combination of these functions determines the position of the orbitals relative to the Cartesian coordinate axes.

For linear combinations Y lm the following notations are accepted:

An additional factor sometimes taken into account in geometric representation, is the sign of the wave function (phase). This factor is significant for orbitals with an orbital quantum number l, different from zero, that is, not having spherical symmetry: the sign of the wave function of their “petals” lying on opposite sides of the nodal plane is opposite. The sign of the wave function is taken into account in the molecular orbital method MO LCAO (molecular orbitals as a linear combination of atomic orbitals). Today science knows mathematical equations, describing geometric figures, representing orbitals (depending on the electron coordinates versus time). These are the equations harmonic vibrations reflecting the rotation of particles in all available degrees of freedom - orbital rotation, spin,... Hybridization of orbitals is represented as interference of vibrations.

Filling of orbitals with electrons and the electronic configuration of an atom

Each orbital can contain no more than two electrons, differing in the value of the spin quantum number s(back). This prohibition is determined by the Pauli principle. The order of filling orbitals of the same level with electrons (orbitals with the same value of the principal quantum number n) is determined by the Klechkovsky rule, the order in which electrons fill orbitals within one sublevel (orbitals with the same values ​​of the principal quantum number n and orbital quantum number l) is determined by Hund's Rule.

Brief entry distribution of electrons in an atom over various electron shells of the atom, taking into account their principal and orbital quantum numbers n And l called

ORBITAL

ORBITAL, in ELEMENTARY PARTICLE PHYSICS - the surface of space around the atomic NUCLEUS in which ELECTRONS can move. Eat Great chance the presence of an electron in such an orbital. It may contain one or two electrons. The orbital has a shape and energy corresponding to the QUANTUM NUMBER of the atom. In molecules, bond electrons move in the combined electric field of all nuclei. In this case, atomic orbitals become molecular orbitals, regions that surround two nuclei that have a characteristic energy and contain two electrons. These molecular orbitals, formed from atomic orbitals, constitute CHEMICAL BONDS.

Atomic orbitals describe the surface around the nucleus of an atom, which most likely contains electrons. They can also be called "energy clouds". Their existence explains chemical bonds. Electrons are contained within atomic or molecular structures, lining up in energy levels. The first level is characterized by only one type of electron: it has one s-orbital (A), shown relative to the x, y and z axes of the atom. Maximum amount electrons that may be on this energy level, equals two. For the second type of electrons, the orbital has the shape of two connected spheres located symmetrically relative to the nucleus. Such an orbital is called a p-orbital (B) V atom three such orbitals, and they are located at right angles to each other (1,2, 3) Orbitals that have regular spherical shapes are conventionally designated as pear-shaped clouds for clarity of the picture . In addition, there are also five d-orbitals (C-G), each of which consists of four pear-shaped lobes on two perpendicular axes, intersecting at the G nucleus - a combination of two p-orbitals.

Scientific and technical encyclopedic dictionary.

See what "ORBITAL" is in other dictionaries:

Orbital: Atomic orbital. Molecular orbital. A list of meanings of a word or phrase with links to relevant articles. If you came here from... Wikipedia

orbital- – a complete set of wave functions of an electron located in the field of nuclides and the averaged field of all other electrons interacting with the same nuclides. Atomic orbital is the allowed state of an electron in an atom, a geometric image,... ... Chemical terms

A function of spatial variables of one electron, which has the meaning of a wave function of an electron located in the field of an atomic or molecular core. If such a function takes into account the spin electron, then it is called. spin O. For more details, see Molecular orbital... ... Physical encyclopedia

orbital- orbitale. physical Atomic and molecular wave functions of an electron located in the field of one or more atomic nuclei and in the average field of all other electrons of the atom or molecule in question. NES 2000... Historical Dictionary Gallicisms of the Russian language

- (from Latin orbita path, track), wave function describing the state of one electron in an atom, molecule, etc. quantum system. In the general case, quantum chemistry. the term O. is used for any function that depends on the variables x, y, z of one... ... Chemical encyclopedia

orbital- orbitalė statusas T sritis chemija apibrėžtis Banginė funkcija, apibūdinanti elektrono judėjimą atome arba molekulėje; erdvė, kurioje elektrono buvimas labiausiai tikėtinas. atitikmenys: engl. orbital rus. orbital... Chemijos terminų aiškinamasis žodynas

orbital- orbitalė statusas T sritis fizika atitikmenys: engl. orbital vok. Orbital, n rus. orbital, f pranc. orbitale, f … Fizikos terminų žodynas

orbital- orbit al, and... Russian spelling dictionary

orbital- With. Orbit buencha bashkaryl torgan. Orbit buencha hәrәkәt itә torgan yaki shunyn өchen bilgelәngәn… Tatar telen anlatmaly suzlege

orbital- A function of spatial variables of one electron, which has the meaning of the wave function of an individual electron in the field of the effective atomic or molecular core ... Polytechnic terminological explanatory dictionary

Books

• Set of tables. Chemistry. Structure of matter (10 tables), . Educational album of 10 sheets.

Atomic orbital The structure of the atom. Electron orbital. Models of atoms of some elements. Crystals. Chemical bond. Valence. Oxidation state. Isometrics. Homology. Art...

Scientists have agreed to call the spherical atomic orbital s orbital. It is the most stable and is located quite close to the core. The greater the energy of an electron in an atom, the faster it rotates, the more its area of ​​residence stretches out and finally turns into a dumbbell-shaped p-orbital:

Orbital hybridization- a hypothetical process of mixing different (s, p, d, f) orbitals of the central atom of a polyatomic molecule with the appearance of identical orbitals that are equivalent in their characteristics.

5.Tetrahedral model of the carbon atom. Butlerov's theory of structure

The theory of the chemical structure of organic substances was formulated by A. M. Butlerov in 1861.

Basic provisions theory of structure boil down to the following:

1) in molecules, atoms are connected to each other in a certain sequence in accordance with their valency. The order in which the atoms bond is called chemical structure;

2) the properties of a substance depend not only on which atoms and in what quantity are included in its molecule, but also on the order in which they are connected to each other, i.e., on the chemical structure of the molecule;

3) atoms or groups of atoms that form a molecule mutually influence each other.

Basic ideas about chemical structure, laid down by Butlerov, were supplemented by Van't Hoff and Le Bel (1874), who developed the idea of ​​​​the spatial arrangement of atoms in an organic molecule. in-va and raised the question of the spatial configuration and conformation of molecules. Van't Hoff's work marked the beginning of the direction of org. Chemistry - stereochemistry - the study of spatial structure. Van't Hoff proposed a tetrahedral model of the carbon atom - the four valences of the atom in carbon in methane are directed to the four corners of the tetrahedron, in the center of which there is a carbon atom, and at the vertices are hydrogen atoms.

Unsaturated carboxylic acids

Chemical properties.
Chemical properties of unsaturated carboxylic acids due to both the properties of the carboxyl group and the properties of the double bond. Acids with a double bond located close to the carboxyl group - alpha, beta-unsaturated acids - have specific properties. In these acids, the addition of hydrogen halides and hydration go against Markovnikov’s rule:

CH 2 =CH-COOH + HBr -> CH 2 Br-CH 2 -COOH

With careful oxidation, dihydroxy acids are formed:

CH 2 =CH-COOH + [O] + H 2 0 -> HO-CH 2 -CH(OH)-COOH

During vigorous oxidation, the double bond is broken and a mixture of different products is formed, from which the position of the double bond can be determined. Oleic acid C 17 H 33 COOH is one of the most important higher unsaturated acids. It is a colorless liquid that hardens when cold. Her structural formula: CH 3 -(CH 2) 7 -CH=CH-(CH 2) 7 -COOH.

Carboxylic acid derivatives

Carboxylic acid derivatives- these are connections in which hydroxyl group carboxylic acid is replaced by another functional group.

Ethers - organic matter having formula R-O-R", where R and R" are hydrocarbon radicals. It should, however, be taken into account that such a group may be part of other functional groups compounds that are not ethers

Esters(or esters) - derivatives of oxoacids (both carboxylic and inorganic) with the general formula R k E(=O) l (OH) m, where l ≠ 0, formally being the products of the replacement of hydrogen atoms of hydroxyls -OH acid function with a hydrocarbon residue (aliphatic, alkenyl, aromatic or heteroaromatic); are also considered as acyl derivatives of alcohols. In the IUPAC nomenclature, esters also include acyl derivatives of chalcogenide analogues of alcohols (thiols, selenols and tellurenes).

Differ from ethers(ethers), in which two hydrocarbon radicals are connected by an oxygen atom (R 1 -O-R 2)

Amides- derivatives of oxoacids (both carboxylic and mineral) R k E(=O) l (OH) m, (l ≠ 0), formally being the products of substitution of hydroxyl groups -OH of the acid function with an amino group (unsubstituted and substituted); are also considered as acyl derivatives of amines. Compounds with one, two or three acyl substituents at the nitrogen atom are called primary, secondary and tertiary amides; secondary amides are also called imides.

Amides of carboxylic acids - carboxamides RCO-NR 1 R 2 (where R 1 and R 2 are hydrogen, acyl or alkyl, aryl or other hydrocarbon radical) are usually called amides; in the case of other acids, in accordance with IUPAC recommendations, when naming an amide, the name of the acidic residue is indicated as a prefix, for example, amides of sulfonic acids RS(=O 2 NH 2 are called sulfonamides.

Carboxylic acid chloride(acyl chloride) is a derivative of a carboxylic acid in which the hydroxyl group -OH in the carboxyl group -COOH is replaced by a chlorine atom. The general formula is R-COCl. The first representative with R=H (formyl chloride) does not exist, although a mixture of CO and HCl in the Gattermann-Koch reaction behaves like formic acid chloride.

Receipt

R-COOH + SOCl 2 → R-COCl + SO 2 + HCl

Nitriles- organic compounds general formula R-C≡N, formally C-substituted derivatives of hydrocyanic acid HC≡N

Capron(poly-ε-caproamide, nylon-6, polyamide 6) - synthetic polyamide fiber obtained from petroleum, a polycondensation product of caprolactam

[-HN(CH 2) 5 CO-] n

In industry it is obtained by polymerization of a derivative

Nylon(English) nylon) are a family of synthetic polyamides used primarily in the production of fibers.

The two most common types of nylon are polyhexamethylene adipinamide ( anid(USSR/Russia), nylon 66 (USA)), often called nylon proper, and poly-ε-caproamide ( nylon(USSR/Russia), nylon 6 (USA)). Other species are also known, for example poly-ω-enanthoamide ( enant(USSR/Russia), nylon 7 (USA)) and poly-ω-undecanamide ( undecane(USSR/Russia), nylon 11 (USA), Rilsan (France, Italy)

Anide fiber formula: [-HN(CH 2) 6 NHOC(CH 2) 4 CO-] n. The anide is synthesized by the polycondensation of adipic acid and hexamethylenediamine. To ensure the 1:1 stoichiometric reactant ratio required to obtain a polymer with maximum molecular weight, a salt of adipic acid and hexamethylenediamine is used ( AG-salt):

R = (CH 2) 4, R" = (CH 2) 6

Nylon (nylon-6) fiber formula: [-HN(CH 2) 5 CO-] n. The synthesis of capron from caprolactam is carried out by hydrolytic polymerization of caprolactam using the “ring opening - addition” mechanism:

Plastic products can be made from rigid nylon - ekolon, by injecting liquid nylon into a mold under greater pressure, thereby achieving greater density of the material.

Classification

KETO ACIDS- organic substances whose molecules include carboxyl (COOH-) and carbonyl (-CO-) groups; serve as precursors for many compounds that perform important biological functions in organism. Significant metabolic disorders that occur in a number of pathological conditions, are accompanied by an increase in the concentration of certain keto acids in the human body

keto enol tautomerism

Methods for obtaining Alpha and Beta keto acids

α-Keto acids are obtained by oxidation of α-hydroxy acids.

β-Ketoacids, due to their instability, are obtained from esters Claisen condensation.

IN organic chemistry the term “oxidation reaction” implies that it is the organic compound, and the oxidizing agent in most cases is an inorganic reagent.

Alkenes

KMnO 4 and H 2 O (neutral medium)

3СH2=CH2 + 2KMnO 4 + 4H 2 O = 3C 2 H 4 (OH) 2 + 2MnO 2 + 2KOH - complete equation

(acidic environment)

the double bond is broken:

R-СH 2 =CH 2 -R + [O] → 2R-COOH - schematic equation

Alkylarenes

Eithlbenzene-alkylarene

Ketones

Ketones are very resistant to oxidizing agents and are oxidized only by strong oxidizing agents when heated. During the oxidation process, rupture occurs C-C connections on both sides of the carbonyl group and in general a mixture of four carboxylic acids is obtained:

The oxidation of a ketone is preceded by its enolization, which can occur in both alkaline and acidic environments:

Wine acid(dihydroxysuccinic acid, tartaric acid, 2, 3-dihydroxybutanedioic acid) HOOC-CH(OH)-CH(OH)-COOH is a dibasic hydroxy acid. Salts and anions of tartaric acid are called tartrates.

Three stereoisomeric forms of tartaric acid are known: D-(-)-enantiomer (top left), L-(+)-enantiomer (top right) and meso-form (mesotartaric acid):

Diastereomers- stereoisomers that are not mirror reflections each other . Diastereomerism occurs when a compound has multiple stereocenters. If two stereoisomers have opposite configurations of all corresponding stereocenters, then they are enantiomers.

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