Category: Chemistry Notes PPT

Acid Strength Definition 

Acid strength can be defined as the tendency of an acid, to dissociate into a proton, H+, and an anion, A−, and symbolized by the formula HA. The dissociation of a robust acid in solution is effectively complete, except in its most concentrated solutions

HA → H+ + A−

Strong acid examples are hydrochloric acid (HCl), perchloric acid  (HClO4),  nitric acid (HNO3), and sulfuric acid (H2SO4).

A weak acid is partially dissociated, with both the dissociated acid and its undissociated product being present, 

In equilibrium with each other.

HA ⇌ H+ + A−.

The best example of a weak acid is Acetic acid  (CH3COOH).

The strength of a weak acid is quantified by its acid equilibrium constant, pKa value.

What is Acid Strength?

The ability of the acid is to lose its H+ ion is the measure of Acid strength

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It depends on several factors which we will discuss in the subsequent sections.

Strong Acids

Strong acid is an acid that dissociates according to the chemical reaction

HA + S ⇌ SH+ + A−

S represents the solvents molecule, like the molecule of water Or DMSO, to an extent that the concentration of the undissociated species HA is too low to be measured.

A strong acid can be completely dissociated for practical purposes,. An example of a robust acid is acid

HCl → H+ + Cl− (in aqueous solution)

Any acid with a pKa value which is a smaller amount than about -2 is classed as a robust acid. This results from the very high buffer capacity of solutions with a pH value of 1 or less and is understood because the leveling effect

Weak Acids

A weak acid is a substance that partially dissociates when it is dissolved in a solvent. In solution, there’s an equilibrium between the acid, HA, and therefore the products of dissociation.

HA ⇌ H+ +A+

The solvent (e.g. water) is omitted from this expression when its concentration is effectively unchanged by the method of acid dissociation. The strength of a weak acid is often quantified in terms of an equilibrium constant, Ka, defined as follows, where [X] signifies the concentration of a chemical moiety, X. 

[H]2/ka + [H]- TH=0

This equation shows that the pH of a solution of a weak acid depends on both its Ka value and its concentration. Typical samples of weak acids include ethanoic acid and hypophosphorous acid. An acid like ethanedioic acid (HOOC–COOH) is claimed to be dibasic because it can lose two protons and react with two molecules of an easy base. Phosphoric acid(H3PO4) is tribasic.

Factors Determining Acid Strength

Different acids have different acid strengths. As already discussed earlier 

If An acid has a greater degree of dissociation it behaves as a stronger acid.

Now allow us to understand the factors on which the strength of an acid depends. The degree of dissociation of an acid depends on the following two factors. 

Strength of H-A bond 

Polarity of H-A bond

In general weaker the strength of H-A bond, stronger is that the acid. And also, greater the polarity of the H-A bond is, stronger is the acid. Both these factors make the dissociation of acid molecules into H+ and A– easier thereby increasing the acidity.

While comparing elements in the same group of the periodic table the strength of the A-H bond is a more important factor in deciding the acidity than its polarity. As the size of A increases on descending a gaggle, H-A bond strength decreases, and thus the acid strength increases. For example, the acid strengths of hydrides of group-17 elements increase in the order. 

HF < HCl < HBr < HI

Fun Facts 

The following is strong acids in aqueous and dimethyl sulfoxide solution. The values of pKa, cannot be measured experimentally. The values within the following table are average values from as many as 8 different theoretical calculations

 

 

Also, in water

• Nitric acid (HNO3), pKa = -1.6 

• Sulfuric Acid (H2SO4), pKa1 ≈ −3 (Only first dissociation)

The following can be used as protonation in organic chemistry

• Fluoroantimonic acid H[SbF6]

• Magic acid H[FSO3SbF5]

• Carborane superacid H[CHB11Cl11]

• Fluorosulfuric acid H[FSO3] (pKa = −6.4)

A class of strong organic oxyacids is Sulfonic acids, such as p-toluenesulfonic acid (tosylic acid).

What is Catalysis? 

The process of increasing the rate of chemical reaction by adding a substance which does not take part in the reaction is called catalysis and the substance which is added and increases the rate of reaction is called a catalyst. A very small amount of catalyst is required to alter the rate of reaction. For example, in the reaction of converting hydrogen peroxide into water and oxygen gas, potassium permanganate is used as a catalyst which increases the rate of reaction. 

2H₂O₂ [overset{text{Potassium permanganate}}{rightarrow}] 2H₂O + O₂

Types of Catalysis 

On the basis of phases of catalysts and reactants, catalysis can be divided into following two types –

What is Homogeneous Catalysis and Catalyst? 

The catalyst who is present in the same phase as of the reactants in the reaction is called homogeneous catalyst and this type of catalysis process is called homogeneous catalysis. 

Examples of Homogeneous Catalysis and Catalysts – 

1. Hydrolysis of Sugar – In hydrolysis of sugar reactants sugar (sucrose solution) and water are used in liquid states and the catalyst sulfuric acid is also used in the liquid state. Reaction is given below –

C₁₂H₂₂O₁₁₍ₗ₎ + H₂₍ₗ₎ [overset{text{H₂SO₄₍ₗ₎}}{rightarrow}] C₆H₁₂O₆₍ₗ₎ + C₆H₁₂O₆₍ₗ₎

Sucrose                           Glucose       Fructose

2. Hydrolysis of the Ester – In hydrolysis of the ester, ester is taken in liquid state with water (liquid) for the reaction in presence of catalyst hydrochloric acid which is also taken in liquid state. Reaction is given below –

CH₃COOCH₃₍ₗ₎ + H₂O₍ₗ₎ [overset{text{HCl₍ₗ₎}}{rightarrow}] CH₃COOH₍ₗ₎ CH₃OH₍ₗ₎.

What is Heterogeneous Catalysis and Catalysts? 

The catalyst whose phase differs from that of the reactants in the reaction is called heterogeneous catalyst and this type of catalysis process is called heterogeneous catalysis. 

Examples of Heterogeneous Catalysis and Catalysts –

1. In Haber’s process of formation of ammonia, nitrogen and hydrogen are used in gaseous forms while catalyst iron is used in solid form. 

[N_{2(g)}] + 3[H_{2(g)}] [overset{text{Fe₍ₛ₎}}{rightarrow}] 2NH₃

2. Formation of Sulfuric Acid – In this process sulfur dioxide (gas) is oxidized to sulfur trioxide (gas) by heterogeneous catalysis in presence of solid V2O5 catalyst. Then sulfur trioxide is hydrolyzed to sulfuric acid. 

[SO_{2(g)}] + [O_{2(g)}] [overset{text{V₂O₅₍ₛ₎}}{rightarrow}] 2 [SO_{3(g)}]

What is Adsorption Theory of Heterogeneous Catalysis? 

Modern Adsorption theory of heterogeneous catalysis is the mixture of moderate compound hypothesis and the old adsorption hypothesis or old adsorption theory. Old adsorption theory lacked specificity so there was a need for modern adsorption theory. 

According to adsorption theory of heterogeneous catalyst, there are free valencies in the catalyst on which reactant molecules get attached. The mechanism of adsorption theory of heterogeneous catalysis involves following steps –

• Step 1. Diffusion of reactant molecules 

• Step 2. Adsorption 

• Step 3. Intermediate complex formation 

• Step 4. Desorption 

• Step 5. Diffusion of product molecules 

Step 1. Diffusion of Reactant Molecules – In this step reactant molecules get diffused towards the surface of the catalyst. 

Step 2. Adsorption – In this step reactant molecules get adsorbed on the surface of the solid catalyst or form loose bonds with the free valencies of the catalyst. 

Step 3. Intermediate Complex Formation – In this step adsorbed reactant molecules on the surface of the catalyst react with each other and form new stronger bonds with each other which leads to the formation of an intermediate. 

Step 4. Desorption – In this step intermediate converts into product as it loses its affinity towards the catalyst. The product molecule gets desorbed from the surface of the catalyst. 

Step 5. Diffusion of Product Molecules – In this step desorbed product molecules from the surface of the catalyst get diffused away from the catalyst. 

This ends our coverage on Adsorption Theory of Heterogeneous Catalysis. We hope you enjoyed learning and were able to grasp the concept. We hope after reading this article you will be able to answer questions based on this topic. If you are looking for solutions to NCERT Textbook problems based on this topic, then log on to website or download Learning App. By doing so, you will be able to access free PDFs of NCERT Solutions as well as Revision notes, Mock Tests and much more.

The common family of hydrocarbons, which is found in crude oil, is the alkenes. In this particular family, there is one carbon-carbon double bond, at least. This double bond makes a major difference in the chemistry of the compounds of the family.

In the chemical industry, the alkenes and particularly ethene, are tremendously essential. They cannot be found in crude oil in very large quantities but they are produced by cracking of the alkanes. The alkenes, like all the hydrocarbons, burn in the air to produce water and carbon dioxide. Ethene reacts in oxygen explosively, and so, it is not much good as a fuel. At the same time, alkenes are also much useful in the chemical industry in the manufacturing of plastics and various other chemicals to be used as fuels.

General Properties of Alkenes

• Physical State – The members containing either two or four carbon atoms are gases; five to seventeen are liquids, and eighteen onwards, solids at room temperature, and also, they can burn in air with a luminous smoky flame.

• Solubility – Alkenes are soluble in organic solvents and insoluble in water, such as benzene and more.

• Density – Alkenes are lighter compared to water.

• Boiling Point – The boiling points of alkenes represent a gradual increase with an increase in the chain length or molecular mass; this indicates the intermolecular attractions become stronger with the increase in the molecule size.

Classification of Alkenes

Alkyl groups bonded to the sp2 hybridized carbon atoms of alkenes affect the double bond stability. The alkene’s chemical reactivity is also often affected by the different alkyl groups that are bonded to the carbon atoms of sp2 hybridized. Therefore, it is very useful to classify alkenes by more number of alkyl groups attached to the C=C structural unit. This feature is known as the degree of substitution.

An alkene, which has a single alkyl group that is attached to the sp2 hybridized carbon atom of the double bond, is monosubstituted. Sometimes, an alkene whose double bond is at the end of the carbon atoms’ chain is also called a terminal alkene. Alkenes having two, three, and four alkyl groups bonded to the carbon atoms of the double bond are disubstituted, trisubstituted, and tetrasubstituted, respectively.

Physical Properties of Alkenes

The physical properties of alkenes are very similar to that of alkanes. Let us look at a few physical properties:

• Alkenes naturally exist in all three states. The first three are gases, the next fourteen are liquids, and the higher than these are all solids.

• Because of the weak van der Waal forces, all alkenes are insoluble in water.

• But alkenes are soluble in organic solvents such as acetone or benzene because here, the van der Waal forces will be replaced by the new ones, making alkenes fully soluble.

• The alkenes’ boiling points depend on their molecular structure. The bigger the alkane’s molecular chain, the higher the boiling points. Therefore, higher alkenes have very high boiling points.

• The polarity of alkenes depends on their functional groups.

Chemical Properties of Alkenes

Alkenes are unsaturated compounds that make them highly reactive. Where most of these chemical reactions happen at the double bonds of Carbon-Carbon, this makes alkenes far more reactive compared to alkanes. Alkenes undergo three types of primary reactions, which are given as follows.

Addition Reactions

Addition of Hydrogen

In the presence of platinum or nickel, alkenes will react to add to its molecular chain one diatomic molecule of hydrogen (or dihydrogen). And they become alkanes in this process due to the rearrangement of atoms.

Addition of Halogens

Halogens will react with alkenes to produce vicinal dihalides. Iodine will not react with alkenes from the halogens. In contrast, bromine reacts with alkenes and will attach at the unsaturated site. Also, the reaction is used as proof of unsaturation.

C2H4(g) +Br2(aq) → C2H4Br2(aq)

Addition of Halides

These reactions follow a specific rule, which is the Markovnikov rule. This rule states the reactant’s negative portion (the molecule that gets added to the chain) will attach itself to the carbon attached with the least number of hydrogen atoms. So, when a hydrogen halide reacts with an alkene, and the hydrogen attaches at the double bond to the atom attached with more hydrogen atoms. On the other hand, the halide ion will attach to that carbon atom, which has the lesser hydrogen atoms attached.

Uses of Alkenes

The list of uses of alkenes of different ones such as propene, ethene, and more is given below.

• Alkene used in the manufacture of polythene bags, and plastics as polythene for making bowls, buckets, bags, and more.

• Making ethane-1,2-diol, to use as an anti-freezing for motor car radiators.

• Polystyrene manufacturing is used in making parts of the refrigerator and car battery cases.

• Synthetic fibre terylene and ethanol manufacturing.

• Manufacture of acrylic fibres.

• Manufacturing polypropene, plastic for making packaging material, and ropes.

• Making an anti-knock for car engines.

• Manufacture of propanol, which can be used in making acetone.

A compound with the general formula RC(=O)NR′R′′, where R, R’, and R′′ represent organic groups or hydrogen atoms, is known as an amide, also known as an organic amide or a carboxamide in organic chemistry. When it appears in the main chain of a protein, the amide group is called a peptide bond, and when it occurs in a side chain, such as in the amino acids asparagine and glutamine, it is called an isopeptide bond. It can be thought of as a carboxylic acid derivative RC(=O)OH with the hydroxyl group –OH substituted by an amine group –NR′R′′, or as an acyl (alkanoyl) group RC(=O)– joined to an amine group. In this article, we will study amide functional group, amide general structure, functional groups amide and monocarboxylic acid amide in detail.

Primary, secondary, and tertiary amines are graded according to whether the amine subgroup has the form –NH₂, –NHR, or –NRR’, where R and R’ are non-hydrogen groups Given below is the amide group structure for primary, secondary and tertiary amide.

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Common Amides

Amides can be found in both nature and technology. Proteins and essential plastics such as Nylons, Aramid, and Kevlar are polymers with amide groups (polyamides) linking their units; these linkages are easy to shape, provide structural rigidity, and resist hydrolysis. Many other essential biological molecules, as well as medications such as paracetamol, penicillin, and LSD, are amides. Solvents with low molecular weight, such as dimethylformamide, are commonly used.

Amide and Amine

The addition of a carbonyl group to an amine has two important effects on the nitrogen’s properties.

For instance, amide nitrogen is much less basic than amine nitrogen. This is largely due to the delocalization of the nitrogen lone pair into the carbonyl’s pi bond. Oxygen, not nitrogen, is the most fundamental position of an amide.

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Second, amide N–H bonds are slightly more acidic than amine N–H bonds. Because delocalization occurs. The conjugate base’s lone pair can be delocalized by resonance to the attached carbonyl group. Acetamide has a pKa that is about 20 orders of magnitude higher than ammonia.

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Amide Solubility

The carbonyl (C=O) is a stronger dipole than the N–C dipole due to oxygen’s higher 

electronegativity. Amides will behave as H-bond acceptors because they have a C=O dipole and, to a lesser degree, an N–C dipole. The presence of N–H dipoles in primary and secondary amides enables them to act as H-bond donors. As a result, amides can hydrogen bond with water and other protic solvents; the oxygen atom can accept hydrogen bonds from water, while the N–H hydrogen atoms can donate hydrogen bonds. As a result of interactions like these, amides have a higher water solubility than corresponding hydrocarbons. These hydrogen bonds play an important role in the secondary structure of the protein.

Synthesis of Amide

1. Nucleophilic Acyl Substitution of Acyl Halides (or Anhydrides) With Amines

With amine nucleophiles, acyl groups attached to a good leaving group, such as acid chlorides or acid anhydrides, can easily undergo nucleophilic acyl substitution.

If only the carboxylic acid is available, converting it to an acid chloride with a reagent like a thionyl chloride (SOCl₂) is a successful first step in converting a carboxylic acid to an amide.

Treating a carboxylic acid with an acyl halide, on the other hand, produces an anhydride, which is also useful.

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2. Hydrolysis of Nitriles 

Nitriles are hydrolyzed to primary amides under acidic or basic conditions

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By reacting amines with a carboxylic acid in the presence of the dehydrating agent.

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Did You Know?

Amino acids are organic molecules that have three functional groups: an amine (–NH₂), a carboxylic acid (–COOH), and a side chain (that is specific to each amino acid). Proteins are made up of the same 20 amino acids in most living organisms. The carboxylic acid group of one amino acid reacts with the amine group of the other amino acid to create a peptide bond, which is a covalent bond formed when the carboxylic acid group of one amino acid reacts with the amine group of the other amino acid. A molecule of water is generated as a result of the forming of the bond (in general, reactions that result in the production of water when two other molecules combine are referred to as condensation reactions). A peptide bond is a type of amide bond. A peptide connection or peptide bond is the product of the carbonyl group carbon atom bonding with the amine nitrogen atom. More peptide bonds may form to other amino acids, expanding the structure, since each of the original amino acids has an unreacted group (one has an unreacted amine and the other has an unreacted carboxylic acid). A polypeptide is a sequence of associated amino acids. At least one long polypeptide chain can be found in a protein.

Ammonium Sulfate is non-unsafe to humans. It is otherwise called DiAmmonium Sulfate or Sulphuric acid diAmmonium salt. It has no smell and dissolves in water with ease. It doesn’t dissolve in acetone. It shows up as a translucent solid white and has a salty taste. It is generally utilized as manure for soil, which contains 21% nitrogen and 24% sulfur. Ammonium Sulfate is an inorganic salt with high solvency that dissociates into Ammonium (NH4)+and Sulfate (SO4)2- in watery solutions. 

 

Ammonium Sulfate is particularly helpful as a precipitant since it is profoundly dissolvable, settles the protein structure, has a moderately low density, is promptly accessible, and is generally economical. Today in this article, we will learn about what is Ammonium Sulfate, what are the properties of Ammonium Sulfate (NH4)2SO4, what does Ammonium Sulfate do, what is Ammonium Sulfate used for, what is ferrous Ammonium Sulfate, and what is Ammonium Sulfate fertilizer.

 

Ammonium Sulfate Structure (NH4)2SO4 

Given below is the structure of Ammonium Sulfate.

 

 

Let us now learn about the different properties of Ammonium Sulfate (NH4)2SO4.

 

Properties of Ammonium Sulfate (NH4)2SO4

 

(NH4)2SO4 Uses Ammonium Sulfate

Let us now learn about what Ammonium Sulfate is used for.

1. Ammonium Sulfate precipitation is a typical technique for protein refinement by precipitation. As the ionic quality of a solution expands, the dissolvability of proteins in that solution diminishes. Ammonium Sulfate is amazingly solvent in water because of its ionic nature, thus, it can “salt out” proteins by precipitation.

2. A high salt focus, which can be accomplished by including or expanding the grouping of Ammonium Sulfate in a solution, empowers protein division dependent on a decline in protein dissolvability; this partition might be accomplished by centrifugation.

3. Precipitation by Ammonium Sulfate is an aftereffect of a decrease in insolvency instead of protein denaturation, in this manner the encouraged protein can be solubilized using standard cradles. Ammonium Sulfate precipitation gives a helpful and straightforward intention to fractionate complex protein mixtures.

4. In the examination of the rubber grids, unpredictable fatty acids are dissected when rubber is accelerated with a 35% Ammonium Sulfate solution, that tends to leave a reasonable liquid from which the unstable fatty acids are recovered with the help of sulfuric acid and afterwards refined with the steam. Particular precipitation with Ammonium Sulfate, inverse to the typical precipitation strategy which utilizes acidic acid, doesn’t meddle with the assurance of unstable fatty acids.

 

What is the Use of Ammonium Sulfate as a Food Added Substance?

As a food added substance, Ammonium Sulfate is viewed as commonly perceived as protected (GRAS) by the U.S. Food and Drug Administration, and in the European Union, it is assigned by the E number E517. It is utilized as an acidity controller in flours and bread.

 

Other Uses of Ammonium Sulfate

1. In the treatment of drinking water, Ammonium Sulfate is utilized in a blend with chlorine to produce monochloramine for disinfection.

2. Ammonium Sulfate is utilized from a more minor perspective in the arrangement of other Ammonium salts, particularly Ammonium perSulfate.

3. Ammonium Sulfate is recorded as an ingredient for some United States vaccines per the Center for Disease Control.

4. Ammonium Sulfate has additionally been utilized in flame retardant creations acting a lot like diAmmonium phosphate. As a flame retardant, it builds the ignition temperature of the material, diminishes greatest weight reduction rates, and causes an expansion in the creation of buildup or burn. Its flame-retardant adequacy can be upgraded by mixing it with Ammonium sulfamate. It has been utilized in flying firefighting.

5. Ammonium Sulfate has been utilized as a wood preservative. However, because of its hygroscopic nature, this utilization has generally ended as a result of related problems with metal clasp corrosion, dimensional unsteadiness, and finish disappointments.

What is Ammonium Sulfate?

Ammonium Sulfate is an inorganic salt that finds its usage in commercial industries. This salt, with no smell, dissolves easily in water. It appears as fine white crystals or as hygroscopic granules. The salt is found naturally in mineral mascagnite in volcanic fumaroles and coal fires at dump yards. Containing 21% nitrogen and 24% sulfur, Ammonium Sulfate is mainly used as a growing plant agent.

Ammonium Sulfate – Properties, Uses, and Structure

Definition

Ammonium Sulfate is an inorganic salt with (NH4)2SO4. Its IUPAC name is Ammonium tetraoxosulphate(VI). It is also known as DiAmmonium Sulfate, sulphuric acid, diAmmonium salt, mascagnite, and dopamine. It is a white odorless solid that sinks and dissolves in water. This salt is made by making ammonia react with sulphuric acid. In several parts of the world, abundant supplies of calcium Sulfate are found in mineral forms. Therefore, calcium Sulfate is used for making Ammonium Sulfate by combining it with ammonia and water. 

Properties of Ammonium Sulfate

Ammonium Sulfate has a molar mass o
f 132.14 g/mol. It appears as fine white hygroscopic granules. Ammonium Sulfate has a density of 1.77 g/cm3. It has a solubility of 70.6 g per 100 g of water. Ammonium Sulfate is insoluble in acetone, alcohol, and ether. (NH4)2SO4 → (NH4)HSO4 + NH3

Ammonium Sulfate is formed by adding finely divided gypsum to an Ammonium carbonate solution.

(NH4)2CO3 + CaSO4 → (NH4)2SO4 + CaCO3

Ammonium Sulfate forms ferroelectric at low temperature below -49.5°C. At room temperature, it crystallizes. This salt’s melting point ranges between 235 to 280 °C. It decomposes upon heating above 250°C. 

Overheating decomposes Ammonium Sulfate to form Ammonium biSulfate, and further heating decomposes it into Ammonium, nitrogen, sulfur dioxide, and water.

Structure of Ammonium Sulfate

Ammonium Sulfate is non-hazardous to humans. The structure of Ammonium Sulfate is:

Ammonium Sulfate has a tetrahedral structure formed by a central nitrogen atom bond with four nitrogen atoms. It also is bonded by a second complexion, the Sulfate anion. The Sulfate anion has a central sulfur atom bonded to 4 oxygen atoms. 

Uses of Ammonium Sulfate

Ammonium Sulfate finds its use in a wide range of industries. Some of its common uses are as follows:

• Used as a fertilizer

• Used as a reagent

Ammonium Sulfate is used as a reagent for molecular biology as it is a good precipitant agent for proteins.

Ammonium Sulfate is recognized as a food additive. It is also used as an acidity regulator in flours and bread.

Ammonium Sulfate is used in the treatment of drinking water. It is combined with chlorine to generate monochloramine for disinfection.

The United States uses Ammonium Sulfate in the preparation of vaccines.

It is used on a small scale to prepare Ammonium salts like Ammonium perSulfate.

The hygroscopic nature makes it  a wood preservative.

Anthracene is a colourless crystalline aromatic hydrocarbon utilised in the chemical industry that is created by distilling natural crude oils. Anthracene is a three-fused benzene ring solid polycyclic aromatic hydrocarbon (PAH) with the formula C14H10. It’s a substance found in coal tar. Anthracene is used to make the red dye alizarin as well as other dyes. It is colourless but fluoresces blue (400–500 nm peak) when exposed to ultraviolet light. This article will study the use of anthracene in detail.

Anthracene Sigma Aldrich

Three benzene rings are fused together to form anthracene, a polycyclic aromatic hydrocarbon. A polycyclic refers to a molecule with more than one ring, aromatic refers to a molecule with alternating double-single bonds all over the ring structure, and hydrocarbon refers to a molecule composed entirely of carbon and hydrogen atoms.

Anthracene Sigma

It is the three rings that were bound together, as well as the network of alternating double and single bonds that ran all the way around them.

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Reactions of Anthracene

1. Anthracene to Anthraquinone

Anthracene is converted to anthraquinone when it is reacted with an oxidising agent like hydrogen peroxide. Anthracene with two carbon-oxygen double bonds at the two middle carbons of the molecule is easily recognised as anthraquinone. Anthraquinone may be formed from direct combustion processes in motor-operated vehicles and engines. They are the extensive category of naturally occurring quinones, together with some of the most crucial native colourants like alizarin, purpurin, munjistin, emodin, chrysophanol, aloe-emodin, physcion, rhein, etc. With over 700 chemicals identified, anthraquinone is the biggest group of natural pigments.

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2. Methyl Anthracene

The Elbs reaction is an organic reaction in which an ortho methyl-substituted benzophenone is pyrolyzed to produce a condensed polyaromatic. The reaction is named after Karl Elbs, a German chemist, who also invented the Elbs oxidation. In 1884, the reaction was written. Elbs, on the other hand, misinterpreted the reaction product due to a lack of understanding of naphthalene structure.

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3. Dibenzo Anthracene

The action of UV light causes anthracene to photo dimerize. The 4+4 cycloaddition results in a pair of new carbon-carbon bonds connecting the dimer, which is known as Dianthracene (or sometimes paranthracene). Thermally or with UV irradiation below 300 nm, it reverts to anthracene. The behaviour of substituted anthracene derivatives is similar. The presence of oxygen has an effect on the reaction.

4. Magnesium Anthracene

Magnesium anthracene is an organomagnesium compound that is almost always isolated as tetrahydrofuran (THF) adduct with three ligands. The air and water sensitive orange solid Mg(C14H10)(thf)3 is made by heating a suspension of magnesium in a thf solution of anthracene.

Use of Anthracene

1. Anthracene is primarily converted to anthraquinone, a dye precursor.

2. Anthracene, an organic semiconductor with a large bandgap, is used as a scintillator for high-energy photon, electron, and alpha particle detectors. Plastics, such as polyvinyl toluene, can be doped with anthracene to create a water-equivalent plastic scintillator for use in radiation therapy dosimetry. The emission spectrum of anthracene peaks between 400 and 440 nm.

3. It is present in wood preservatives, insecticides, and coating materials.

4. Anthracene is widely used as a UV tracer in printed wiring board conformal coatings. The anthracene tracer allows for UV inspection of the conformal coating. Anthracene is also used in anthraquinone use.

5. Anthracene derivatives are used in a number of applications. 1-hydroxyanthracene and 2-hydroxyanthracene are hydroxylated derivatives of phenol and naphthols, and hydroxyanthracene (also known as anthrol and anthracenol) is pharmacologically active. 9,10-dihydroxy anthracene is an example of anthracene with several hydroxyl groups.

6. During combustion processes, anthracene, like many other polycyclic aromatic hydrocarbons, is produced. Tobacco smoke and consumption of food tainted with combustion materials are the primary sources of human exposure.

7. Anthracene is non-carcinogenic, as according to several studies it “consistently gives negative results in numerous in vitro and in vivo genotoxicity experiments.” Since crude samples were tainted with other polycyclic aromatic compounds, early studies suggested otherwise. It is also easily biodegradable in soil. In the presence of light, it is particularly vulnerable to deterioration.

8. It is also used as a smokescreen, scintillation counter crystals, and inorganic semiconductor research.

 

Did You Know?

A polycyclic aromatic hydrocarbon (PAH) is a hydrocarbon with many aromatic rings and is a chemical compound containing only carbon and hydrogen. The aromatic hydrocarbons are a significant subset of this category. Naphthalene, which has two aromatic rings, and the three-ring compounds anthracene and phenanthrene are the most basic of these chemicals. This principle is also known as polyaromatic hydrocarbon or polynuclear aromatic hydrocarbon. PAHs are non-polar, uncharged molecules with unique properties owing to delocalized electrons in their aromatic rings. Many are contained in coal and oil fields, as well as the thermal decomposition of organic matter in engines and incinerators, or when biomass burns in forest fires.

Polycyclic aromatic hydrocarbons are addressed as potential starting materials for the abiotic synthesis of materials needed by life’s earliest forms. When inhaled, Anthracene can irritate the throat, nose and lungs leading to wheezing and coughing. Contact to the skin may cause irritation, burns, itching which is provoked by sunlight. Regular contact may cause thickening of the skin and changes in pigment. Studies show, Anthracene may turn into an allergy and once the allergy is developed completely in an individual even very low future exposure can cause a skin rash.

How to Identify Anthracene?

Anthracene is between colourless to pale yellow, which feels like sand when touched with a bluish glow. Exposure to such harmful substances should be regularly checked thoroughly. It may include collecting personal samples and surrounding samples. Remember you have a legal right to this information under OSHA 1910.1020. You can obtain copies of samples from your respective employer. If you feel you are experiencing any health problems due to the natur
e of your work, see a doctor who has expertise in recognizing occupational diseases. 

How to Reduce Exposure to Anthracene?

Use local exhaust ventilation where the chemical is released. If local exhaust ventilation is not suitable for the job make sure to use respirators which can be worn easily. Protective work clothing will help to reduce exposure. After exposure to anthracene, immediately wash at the end of the shift. Wear a face shield along with safety glasses when working with toxic substances to protect your eyes. Never use contact lenses while working with such substances.

Dimerization of Anthracene

When we expose anthracene to ultraviolet light, it undergoes a dimerization reaction. This occurs when two anthracene molecules join together to produce a bigger hydrocarbon structure. Also, the prefix “di” in dimerization signifies ‘two’ (e.g. two molecules of anthracene)

Compounds like anthracene dimers and other polycyclic aromatic hydrocarbons play a key part in organic semiconductors in terms of utility. They’ve also gotten a lot of interest from scientists for their potential use as organic materials in solar panels to harness the sun’s energy.

Oxidation of Anthracene

When anthracene is exposed to an oxidising agent such as hydrogen peroxide, it is converted to anthraquinone. Anthracene with two carbon-oxygen double bonds at the two middle carbons of the molecule is easily identified as anthraquinone.

Interesting facts 

The melting point of Anthracene is 218 degrees Celsius and the boiling point is 354 degrees Celsius. When Anthracene is at its purest form it is colourless. When anthracene is exposed to daylight it darkens. It is quite soluble in carbon disulfide but insoluble in water. However, Anthracene is relatively soluble in methanol, ethanol, chloroform, benzene, etc.