Introduction to compounds and elements
Compounds:
The compound is defined as a pure substance containing two or more elements which are combined together in a fixed proportion by mass.
Elements:
An element is the simplest or basic form of a pure substance which cannot be broken into anything simpler than it by physical or chemical methods. The pure substance which is made up of one kind of atoms only. The common examples of elements are hydrogen, carbon, , sulphur, gold etc.
Elements are further classified into three types.
Metals
Non-metals
Semi-metals
There are few elements which possess the characteristics of both metals and non-metals. These are actually border-line elements and are known as semi-metals. Semi-metals are also called as metalloids. A few common examples are: Arsenic, Antimony and Bismuth.
Types of elements based on physical states:
Based on physical states, the elements have been classified as solids, liquids and gases.
Solid elements: Most of the elements are solids at room temperature. For example, copper, silver, gold, potassium, carbon (diamond, graphite), iodine, phosphorous etc.
Liquid elements: Only mercury and bromine exist as liquid at room temperature. Gallium and cesium become liquids at a temperature 302 K and 303 K respectively. These are slightly higher than the room temperature (298 K).
Gaseous elements: Eleven elements exist in the gaseous state at room temperature. These are hydrogen, oxygen, nitrogen, fluorine, chlorine, helium, neon, argon, krypton, xenon and radon.
A compound is also a pure substance like elements. But it represents a combination of two or more elements which are combined chemically.
Types of compounds
The compounds have been classified into two types
Organic compounds
Organic compounds are the compounds which are obtained from living beings (plant and animal). It has been found that all the organic compounds contain carbon as their essential constituent. The organic compounds are quite often known as carbon compounds.
Examples: Methane, ethane, propane, alcohol, etc.
Inorganic compounds
Inorganic compounds have mostly obtained from non-living sources such as rocks and minerals.
Example: Salt, marble, washing soda, baking soda, etc.
Characteristics of compounds:
Phenol is more important than most people realize. It can be found in many consumer products including aspirin, head lights, gas tanks, billiard balls, nylon, wintergreen gums, Pepto Bismol, deodorant and more. A side product in the manufacture of phenol is acetone which is also used in the private sector in plastics, solvents, and more.
The high-yield manufacture of phenol uses the concepts of peroxidation and cleavage. Cumene (i-propyl benzene) is oxidized by exposure to air to temporarily produce cumene hydroperoxide. The cumene hydroperoxide is simply cleaved at the top of the benzene ring using an acidic catalyst to produce the two usable products of phenol and acetone. The catalyst is extracted and the phenol/acetone mixture is fractionated and purified. Under optimal conditions, 1.31 tons of i-propyl benzene (cumene) will produce 1 ton of phenol and 0.615 tons of acetone. The end-product phenol purity is at 99.99 wt % with total impurities of only 60 ppm. This process is termed the Hock process after being discovered by Hock and Lang in 1944. This process was ideal since both products were useful and relatively pure. Modern demand, however, for phenol is increasing at a higher rate than acetone. This means that the future may classify acetone as a partial waste product. More information on the Hock Process of manufacturing Phenol can be found here which expands on the Benzene-Free Synthesis of Phenol or here which discusses Selective decomposition of cumene hydroperoxide into phenol and acetone by a novel cesium substituted heteropolyacid on clay.
In the syntheses of aromatic esters and ethers, CsF-Celite has been found to be a very efficient, convenient and practical reagent. In fact, it is used for the coupling reactions of a number of aromatic and heteroaromatic phenols with alkyl, acyl or benzoyl halides.
Many other organic reactions have recently been catalyzed by CsF-Celite, such as the reactions to synthesize carboxylic esters, γ-lactones, N-alkylation of anilines, or carboxamides.
