Importance and object of study of organic chemistry
His initial task was to study the substances were in the living nature. Gradually, however, were taking a greater importance for obtaining artificial substances, many of which are not found in nature. In their own study of natural substances, from grade to grade went from the simple to the most complex, and then also to the study of the chemical processes that form the basis of life activity. Contemporary organic chemistry studies both natural substances, as well as synthetic organic substances, the structure of these, their means of obtaining, their properties and possibilities of practical use.
General properties of organic compounds
Carbon is an essential element in organic compounds and in almost all organic substances also found hydrogen. Furthermore containing oxygen and nitrogen, and less frequently in their preparation halogens, sulfur and fsforo.Los Typical organic compounds characterized by certain properties which differ from the properties of inorganic substances. As the vast majority of the inorganic compounds are solids with high melting temperature, a large part of the organic compounds are liquids of low melting temperature. Many reactions of organic substances that pass more slowly inorganic reactions, whilst transformations are often in several directions simultaneously. The organic compounds decompose at high temperatures, most of them generally are oxidized in air. In general it can be said that the organic substances are typically less stable than typical inorganic.
The main constituents of the organic substances are carbon (C), EI hydrogen (H), oxygen (O) and nitrogen (N). Are also often sulfur, phosphorus, chlorine etctera.Los organic compounds which are constituted only of carbon and hydrogen are known as to its composition hidrocarburos.Teniendo hydrocarbons are organic compounds the chemical structure sencillos.Atendiendo molecules of hydrocarbons are classified by the type of bond between the carbon atoms in saturated and unsaturated hydrocarbons and in the form of the carbon chain aliphatic hydrocarbons and unsaturated hydrocarbons cclicos.En carbon-carbon bonds are simple. Examples of these are the alkanes and cycloalkanes:
In unsaturated hydrocarbons have at least one double or triple bond between two carbon tomos chain. These include alkenes (double bond) and alkynes (triple bond).
In its aliphatic or alicyclic hydrocarbons are opened carbonated chains (linear or branched), as in alkanes, alkenes and cyclic hydrocarbons are alquinos.Los closed chain alicyclic and can be, for example, cycloalkanes, and aromatics. The latter are related to benzene.
Saturated hydrocarbons or alkanes. Homologous series
A series of compounds of the same chemical function having similar structures and properties, and which differ in their composition one or several-CH2-groups form a series series homloga.Los members are called homologous. The following table shows the first five homologous series of saturated hydrocarbons.
“Hydrocarbons. Nomenclature and chemical notation of saturated hydrocarbons
Straight chain alkanes: These alkanes are named with a prefix that indicates the number of carbon atoms in the chain, followed by the suffix anus in the table below shows the names of the top 10 of the homologous series alkanes methane.Something to be considered is the presence of alkyl groups, which are formed by removing a hydrogen atom in the saturated hydrocarbon molecule. These groups are attached to otos atoms or groups of atoms. Changing the termination named anus yl alkane or suffix yl. For example, if the molecule of methane (CH4) is eliminated hydrogen atom is obtained methyl or methyl group-CH3, the ethane molecule forms the ethyl or ethyl group (C2H5), and so sucesivamente.De Branched Chain: The branched chain saturated hydrocarbons are named governed by the following rules:
* 1. Selecting the longest chain or main chain are numbered starting with the closest end having a branch. If two branches are equally distant from the ends, are renumbered starting from closest to the easiest.
* 2. Alkyl groups are named in alphabetical order, a number indicating if necessary, the position in the main chain.
* 3. The numbers are separated from the names of the radicals by dashes and when multiple numbers separated by commas. The names of the groups are added as suffix to the name of the main chain basic.
Nomenclature and notation unsaturated hydrocarbon chemistry
Alkenes: To appoint the same prefixes are used in the alkanes followed by the suffix ene, and considering these rules:
* 1. Selecting the longest chain containing double bond.
* 2. Chain is numbered, beginning with the end closest to the double bond.
* 3. In the case of four or more alkenes of carbon atoms indicates the position of the double bond with a number, which is placed before the name of the main chain, separated by a hyphen.
* 4. If the chain is branched alkyl groups are named in alphabetical order, a number indicating, if necessary, their position in the backbone. if so, proceed as in alkanes, bearing in mind the above three rules.
* 5. If the string exists in other constituent, such as halogens, then the alkene is named analogously to what is done in halogenated alkanes according to the above rules.
Alkynes: nomenclature for these compounds differs only in the termination alkenes therefore placed yne.
1. – Halogenated.
Are hydrocarbons containing in the molecule halogen atoms. Sometimes are named as alkyl halides
The halogenated or halogenated compounds, as the name says are compounds containing halogens. Some of the halogenated compounds are halogenated hydrocarbons, ie with halogens hydrocarbons (dichloromethane, difluoropentano).
Halogenated compounds belonging to the functional group of the halogen atoms. They have a high density. They are used as refrigerants, solvents, pesticides, moth repellents, in some plastics and biological functions: thyroid hormones. For example, chloroform, dichloromethane, thyroxine, Freon, DDT, PCBs, PVC. The structure of the halogenated compounds is RX, wherein X is fluorine (F), chlorine (Cl), bromine (Br) and iodine (I)
2. – Rules to follow to assign names to halogenated.
They are named by prefixing the name of halogen (fluorine, chlorine, bromine, iodine) at the corresponding hydrocarbon with a number indicating its position. If there is a substituent in the side chain, then it is numbered beginning with the carbon atom bonded to the main chain, the side chain is enclosed in parentheses The position of the halogen atom indicated by locators.
If there are double and triple bonds, the chain is numbered so that they correspond to the unsaturations smaller locators.
By naming the branched chain halogenated, the halogens are considered radical and cited in their rightful place in the alphabetical order.
3. – Write the name of halogenated following:
4. – Write the structural formulas of the halogenated following:
Oxygen compounds of Hydrocarbons
Alcohols: Classification. Homologous series. Nomenclature and chemical notation. Physical Properties. Isomerism.
* Alcohols are organic compounds consisting of carbon, oxygen and hydrogen, and having in their structure one or more hydroxyl groups (-OH) attached to the carbon chain. This carbon chain or branched alkyl group may be substituted and be open or or cclica.Clasificacin: Depending on their structure are classified according to the number of hydroxyl groups in the carbon chain and the type of carbon to which is attached the group-OH.Segn the number of hydroxyl groups in the carbon chain may be monohydric alcohols (having an-OH group) and polyhydric alcohols (having more than one-OH group). Examples of these are as follows: monohydric: CH3 – OH (Methanol or methyl alcohol) polyhydric: OH – CH2 – CH2 – OH (1,2-ethanediol or ethylene glycol) If in a hydrocarbon carbon chain atom is replaced hydrogen for a hydroxyl group is an alcohol monohidroxilados.Los polyhydric alcohols with two hydroxyl groups attached to the carbon chain diols or glycols are named, and three, triols. these are merely replacing two three hydrogen atoms, respectively, in a hydrocarbon molecule, for an equal number of groups the polyhydric alcohols hidroxilos.En the – OH groups are attached to different carbon atoms and that two groups hydroxyls bonded to the same carbon atom gives rise to a compound type inestable.Segn the carbon to which is attached the – OH group can be primary alcohols, secondary alcohols and reciarios.En primerios the hydroxyl group (-OH) is attached to a primary carbon in secondary alcohol, a secondary carbon, and tertiary alcohols, to a tertiary carbon, which can be represented in general form as follows:
In the above representations-R groups (alkyl groups or carbon chains) may be the same or diferentes.A An example of each of these alcohols:
Homologous series: The following table provides some examples of the homologous series of ethanol:
Physical properties: Similarly to what occurs in the homologous series of hydrocarbons studied the physical properties of the alcohols vary with increasing molar mass. The boiling temperature and density increase sequentially increases as the number of groups metileno.De values of boiling temperatures and melting may infer that temperature and pressure are not in gaseous alcohols. Under these conditions the alcohols of up to twelve carbon atoms are liquids and other solids. Alcohols have a density greater than the respective alkanes, but are still less dense than agua.La alcohols solubility in water decreases with increasing molar mass. The alcohols of up to four carbon atoms are soluble in water. With increasing carbon chain predominantly apolar part in the molecule and, therefore, the solubility in water decreases and increases solubility in apolar solvents.
Nomenclature and chemical notation of monohydric alcohols.
According to the IUPAC naming rules are monohydric alcohols:
1st. Selecting the longest carbon chain contains the group-OH.
2nd. Chain is numbered starting at the end closest to the carbon atom which is bonded to the hydroxyl group.
The 3rd position is indicated with a hydroxyl group number (in alcohols with more than two carbon atoms), which is placed before the name of the main chain separated by a hyphen.
4to. If the branched chain is equally applicable in the case of hydrocarbons. 5th. Renamed the alkane corresponding to the main carbon chain or replacing the ol final completion.
Simple alcohols are also known by their common names, which are formed with the word alcohol followed alchemical group. For example, methyl alcohol (methanol), ethyl alcohol (ethanol), propyl alcohol (1-propanol), etc..
* Chain isomerism.
The chain isomerism of these compounds manifests different structures in the same alcohols qualitative and quantitative composition as a consequence of the existence of branches in the carbon chain of one or more of these.
The order of attachment of the atoms in the molecules of one of the compounds represented is different from the other two.
* Positional isomerism.
This type of isomerism is the position different from the functional group in this case the
-OH group on the carbon chain alcohols having the same qualitative and quantitative composition:
* Function isomerism.
The function isomers are compounds having the same qualitative
and quantitative, but different functional group.
Aldehydes and Ketones: Classification. Homologous series. Nomenclature and chemical notation. Physical Properties. Isomerism.
The aldehydes and ketones, alcohols like are oxygenated organic compounds. In nature many aldehydes are high molar mass, for example, octanal (C8H16O) nonanal (C9H18O) and decanal (C10H20O) found as components of some essential oils contained in flowers and plants which provide the characteristic odor, What is the functional group of these substances What influence does this in the physical properties of aldehydes and ketones What type of isomerism occur
The aldehydes and ketones are those compounds having the carbonyl group C = O, one of the most important groups in organic chemistry. For this reason, they are often called carbonyl compounds.
Aldehydes have the carbonyl group bonded to a carbon atom and one hydrogen (except in the case of the first member of the homologous series in which the group is linked to two hydrogen atoms). The ketones are compounds in which the carbonyl group is bonded to two carbon atoms.
The aldehydes of general formula is of RCHO and ketones is RR’CO.
The first representative of the homologous series of the aldehyde is formaldehyde and methanal or ketones of the propanone.
Representation, name and various physical properties of some members of the homologous series of methanal and propanone.
Chemical Nomenclature and notation of aldehydes and ketones
In the system of the IUPAC (IUPAC English) the names of the aliphatic aldehydes are formed by replacing the end of the name or the alkane corresponding to the termination.
As the carbonyl group is at one end of the chain of carbon atoms is not necessary to indicate its position, as it is typical of a primary carbon to which is assigned the Nro1. When other substituents are present it is necessary to note the position they occupy.
Many aldehydes are also common names. In the following examples these are shown in brackets:
The names of the aliphatic ketones or are formed by substituting the corresponding alkane name with one termination. Then the chain is numbered so that the carbonyl group with the fewest possible and uses this number to indicate its position.
Isomerism chain aldehydes and ketones.
Among the ketones of more than four carbon atoms shows the positional isomerism. This type of isomerism arises between like ketones overall formula, in which the carbonyl group is at different positions in the hydrocarbon chain.
The aldehydes and ketones in the same qualitative and quantitative composition are isomers binding
Carboxylic Acid: monocarboxylic acids. Homologous series. Physical Properties. Structure.
Monocarboxylic organic acids are compounds which have, in the chain at least one
to an alkyl group. If the group would be written aromatic Ar. The chain may be linear, branched or cyclic. Aliphatic acids with a carboxyl group are named fatty acids, since many may be obtained by the hydrolysis of fats (fats are substances that form the fatty tissue of animals, are also found in plants, seeds and in some fruits).
The table shows the first five straight chain acids, which shows the difference of a methylene (CH2), between neighboring Member.
Saturated aliphatic acids having up to 10 carbon atoms are liquid, while the higher homologues are solid at room temperature.
The boiling temperatures increase with increasing CH2 groups when compared with alcohols of the same number of carbon atoms is noted that the monocarboxylic acids are greater.
The melting temperatures vary irregularly shaped, as shown in the graph. In the series of aliphatic acids, density decreases with chain lengthening it influences most the volume of the molecule represented by the increase in mass of the methylene group (CH2).
The electronics of an acid formula rnonocarboxlico depicted as follows:
Melting temperatures of monocarboxylic acids with respect to the number of carbon atoms in the molecule.
Nitrogen compounds of Hydrocarbons
“Nitrogen compounds Amines ::: hydrocarbons. Classification
Amines are organic nitrogen compounds which may be considered as derivatives of ammonia, which are substituted one or more hydrogen atoms by groups (alkyl or aryl). Depending on their structure are classified into: a) primary, secondary and tertiary amines depending on the number of substituted hydrogen atoms in the molecule of ammonia, alkyl or aryl groups. The primary amines have an alkyl or aryl group, secondary and tertiary two three. The substituent groups R, R ‘, R” may be the same or different. The following table shows a representation of the foregoing.
b) aliphatic and aromatic amines, depending on the type of substituents: aliphatic amines are when R, R and R” are alkyl groups, aromatic and if at least one of these groups is arilo.Ejemplos:
Application of organic substances
Ethers intoxicating stimulant component:
Extractor Carboxylic Acids:
Preparation of vinegar, esters, salts, artificial oils, dyes, soaps, cosmetics, lubricants Aldehydes and Ketones
Obtaining synthetic resins
Preservation of anatomical parts
Obtaining Exogenous or HMX (explosives)
Preparation of Vinyl Resins
Preparation of smokeless powders
Chloroform and Iodoform obtaining Amines:
Production of pharmaceuticals
Manufacture of Nylon
Streptococcal infections, staph and bacterial Esters
Preparation of essences and perfumes, margarines, paints, car paints, flat paints, polishes, disc arrays, soaps Amides:
Manufacture of Nylon
Unit # 2
Classification of substances
There are two fundamental criteria for classifying substances, one is based on the composition and the other considers the type of particle that is. Considering the composition, substances are classified as simple (formed by atoms of the same chemical element) and compound (composed of two or more atoms of different elements). This is summarized in the following scheme.
Depending on the type of particles or elementary entities (atom, molecule, ion) substances are classified in atomic, ionic and molecular.
This new classification that takes into account the type of link, but takes into account the structure property relationship and connection type of substances, which is reflected in the following tables:
* The substances are classified as simple and compound composition.
* Substances are classified in atomic, molecular and ionic depending on the type of particles.
* The simple substances can be atomic or molecular.
* The substances can be made atomic, molecular or ionic.
2.2 Nomenclature and notation chemical substances.
It is called the chemical notation and nomenclature consistent set of rules for naming and formulate substances. The chemical formula is conventionally written representation of the composition of a substance from the symbols of the elements that constitute it. These rules in their application depends on the classification of substances according to their composition and particle type.
Recall the prefixes that indicate numbers:
Mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca, undec, dodec, TRIDEC.
Simple substances are classified into metals and nonmetals and can be atomic or molecular naming how
Simple atomic substances: The name matches the element and the formula is the element symbol both metallic and non-metallic.
Examples: Name Formula
Molecular simple substances: similar to are named atomic prepending to name but a prefix indicating the number of atoms forming the molecule. In this formula indicates a number sudndice.
Composite substances: how are named and formulated
* Remember that these are classified according to their composition in oxides, hydroxides and salts.
* Usually takes into account two criteria:
a) The number of particles present in the formula.
b) The oxidation number of the atom of the element which forms the substance when this is variable.
Chemical Nomenclature and oxides notation.
The first criterion is generally used for non-metal oxides and the second metal oxides.
Metal oxide: They are named with the generic word oxide followed by the preposition of, and then the name of the metallic element (if the element has variable oxidation number places the absolute value of the number with a Roman numeral in parentheses).
For notation type metallic element symbol first and then the oxygen. Subscript stands as the absolute value of the oxidation numbers of each element exchanged, and if they are divisible by the same number are divided.
Nonmetallic oxide: like are named metal oxides, but using prefixes which indicate the number of atoms of each element in the chemical formula.
The prefix mono for nonmetal often omitted as the number 1 as subscript.
To notice is made similarly to the metal oxides, but the subscripts placing only the name prefix indicating the number of atoms of each element.
In short notation nomenclature and chemical oxides is reflected in the following table:
Chemical Nomenclature and salts notation.
Salts are ionic substances neutral, that is formed by positive and negative ions. The ions may be monatomic (single atom: Cl-, Mg2 +) or polyatomic (several atoms: NO3, SO4). The salts according to their composition can be binary (atoms of two elements: NaCl), ternary (three elements atoms: Na2SO4) and quaternary (atoms of four elements: NaHCO3).
In general the salts are named as follows:
Name anion, preposition, name of the cation. (If the cation of the metal element has variable oxidation number, place the same absolute value with a Roman numeral in parentheses).
Sales binary: They anion is monatomic and write the name of the nonmetallic element terminated uro.
To formulate salts formula binary type of cation and anion then placed as subscript and the absolute value of the charge on each ion exchanged and if divisible by a same number of splits.
Ternary salts: To name or note is similarly applicable to salts binary, changing only the name of the anion in this case is a polyatomic ion. Polyatomic.
The metal hydroxides are classified or non-metallic and both groups differ in their chemical properties. Thus, generally metal hydroxides have basic properties, and no metallic hydroxides acidic properties. Accordingly, in the nomenclature and chemical notation using two different criteria:
a) metal hydroxides: are generally ionic compounds, and as such are named and formulated. In this case the anion is hydroxide, and have, for example:
b) hydroxides non-metals are generally molecular substances, which manifest acidic properties, releasing easily the hydronium ion H + in solution, so named as acid, ie with the generic word acid followed by the name of the anion polyatomic changing the ending-ato by-ico or termination by-bear-ito.
Notation: the first symbol is written hydrogen (H), followed by anion representation or formula and placed as hydrogen subscript absolute value of the charge of the anion (there is always one anion for these hydroxides).
The application of chemical nomenclature and notation of the substances are summarized in the table below for examples of different kinds of substances with your name and chemical formula.
2.3 The chemical reactions.
Chemical reactions are processes in which structural changes occur, such as the breaking and formation of new chemical bonds, giving rise to new substances and to pass with absorption or release of heat energy.
Among the events that can demonstrate the occurrence of a chemical reaction are indicated as follows:
* Changes in color.
* Fading a solid.
* Gas evolution.
* Variation of electric conductivity.
* Detachment energy as heat.
A chemical reaction is represented by a chemical equation.
The qualitative interpretation of the chemical equation expresses qualitatively the nature of the reactants and products, and from the point of view expressed quantitative relationship of proportionality between the various quantities characterizing samples of substances [N (x), n (x) , m (x), v (x)] so you should always use the term “per” (both in one).
Information obtained from a chemical equation.
Qualitative Information: The solid calcium reacts with dioxygen gas, and solid calcium oxide produces, shedding as heat energy.
* N (x) for every 2 reacts calcium atoms and 1 molecule of dioxygen 2 elementary entities are produced from calcium oxide.
* N (x) for every 2 mol of calcium reacts 1 mol produce dioxygen and 2 mol of calcium oxide and emerges as heat energy.
* M (x) for every 80 g of reactive calcium and 32 g of dioxygen produced 112 g of calcium oxide and emerges as heat energy.
Classification of the chemical reactions.
In the classification takes into account two criteria:
1 – The heat energy involved in the chemical reaction.
2 – variation or no oxidation number of atoms of the elements
forming substances involved in the chemical reaction.
According to the energy criterion are classified reactions exothermic (release energy as heat) and endothermic (absorbs energy as heat).
Considering the variation or not the number of oxidation reactions are classified redox (if varies oxidation number of atoms of the elements during the process) or redox (if not change the oxidation number).
2.4 Relations between the masses of substances involved in a chemical reaction.
Recall first some quantities characterizing the samples of pure substances and defining equations that relate:
Magnitudes: substance mass m (x) Unit: g —- g
amount of substance n (x) —- mole mol
volume of substance V (x) L —- liter
There are two laws that are true for all chemical reactions: the law of conservation of mass (Lomonosov-Lavoisier law).
The law of conservation of mass states that:
“In a chemical reaction, the total mass of the reactants is equal to the total mass of products substances”
(The total mass is the sum of the masses of each of the substances involved in this part of the process).
In the equation for the chemical reaction of calcium with the dioxygen:
Unit # 3. The thermochemical and kinetic behavior of chemical processes