Sulfonic acid is
a compound with general formula RSO2OH, where R is an
aliphatic or aromatic hydrocarbon. It is a derivative of sulfuric acid
(HOSO2OH) where an OH has
been replaced by a carbon group or a compound where a hydrogen atom has been
replaced by treatment with sulfuric acid; for example, benzene is converted to
benzenesulfonic acid (water-soluble). Sulfonic acid has a sulfur atom bonded to
a carbon atom of a hydrocarbon and bonded also to three oxygen atoms, one of
which has been attached to a hydrogen atom. Sulfonic acid is acidic due to the
hydrogen atom, stronger than a carboxylic acid. Sulfonic acid is one of the most
important organo sulfur compounds in organic synthesis. Sulfonic acids are used
as catalysts in esterification, alkylation and condensation reactions.
Sulfonates are salts or esters of sulfonic acid. Sulfonic salts are soluble in
water. Sulfonic acid and its salts present in organic dyes provide useful
function of water solubility and or improve the washfastness of dyes due to
their capabiltity of binding more tightly to the fabric. They are widely used in
the detergent industry. Alkylbenzene sulfonic acid is the largest-volume
synthetic surfactant because of its relatively low cost, good performance, the
fact that it can be dried to a stable powder and the biodegradable environmental
friendliness. Sulfonate cleaners do not form an insoluble precipitates in hard
water. Sulfonic acid salts and esters are intermediates widely used in organic
synthesis and particularly phenolic compounds and cation exchange resins. They
are synthetic intermediates for a number of biologically active compounds and
pharmaceutical candidates such as sulfa drugs.
Amide is a group
of organic chemicals with the general formula RCO-NH2 in which a carbon
atom is attached to oxygen in solid bond and also attached to an hydroxyl
group, where 'R' groups range from hydrogen to various linear and ring
structures or a compound with a metal replacing hydrogen in ammonia such as
sodium amide, NaNH2. Amides are divided
into subclasses according to the number of substituents on nitrogen. The primary
amide is formed from by replacement of the carboxylic hydroxyl group by the NH2,
amino group. An example is acetamide (acetic acid + amide). Amide is obtained by
reaction of an acid chloride, acid anhydride, or ester with an amine. Amides are
named with adding '-ic acid' or '-oic acid' from the name of the parent
carboxylic acid and replacing it with the suffix 'amide'. Amide can be formed
from ammonia (NH3). The secondary and
tertiary amides are the compounds which one or both hydrogens in primary amides
are replaced by other groups. The names of secondary and tertiary amides are
denoted by the replaced groups with the prefix capital N (meaning nitrogen)
prior to the names of parent amides. Low molecular weight amides are soluble in
water due to the formation of hydrogen bonds. primary amides have higher melting
and boiling points than secondary and tertiary amides. Anilide is an amide derived from aniline by substitution of an acyl group for
the hydrogen of NH2. Acetanilide is from acetic acid and aniline. Acetanilide is an odourless,
white flake solid or crystalline powder (pure form);
soluble in hot water alcohol, ether, chloroform,
acetone, glycerol, and benzene;; melting point 114 C and boiling point 304 C;
can undergo self-ignite at 545 C, but is
otherwise stable under most conditions. Acetanilide which can be obtained by
acetylation of aniline
undergoes
nitration at low temperature and yields highly the para-nitro products. Acetyl group can then be removed by acid-catalyzed hydrolysis to yield para-nitroaniline. Although the activating affection
of the
amino group can be reduced, the acetyl derivative remains an
ortho/para-orientation and activating substituent. Examples of
aromatic anilide are
benzanilide,
C6H5NHCOC6H5 or
Carbanilide (N,N'-diphenylcarbamide). Some structural amides are;
- Acetamides
- Acrylamides
- Anilides
- Benzamides
- Naphthylamides
- Formamides
- Lactams
- Salicylamides
- Sulfonamides
- Thioamides
- Fatty
amides
An amide is
hydrolyzed to yield an amine and a carboxylic acid under strong acidic
conditions. The reverse of this process resulting in the loss of water to link
amino acids is wide in nature to form proteins, the principal constituents of
the protoplasm of all cells. Sulfonamides are analogs of amides in which the
atom attached to oxygen in solid bond is sulfur rather than carbon. Polyamide
is a polymer containing repeated amide groups such as various kinds of nylon and
polyacrylamides.
o-Toluenesulfonamide has been the parent material for the production of
saccharin. In the phase of either solid or liquid, large amount of
toluenesulfonamide class substances including the mixtures of N-ethyl-o/p-toluene sulfonamides,
N-methyl-o/p-toluene sulfonamides and o/p-toluene sulfonamides are used as flow-promoting agents for
paints, adhesives, nitrocellulose, coating materials and as plasticizers for
polyamides and other thermosetting resins to increase flexibility. They promote
the resistance to oils, greases, and solvents. They are used as antistatic
agents and as gloss enhancers in plastic film preparations. They are used as
basic material of electroplating solutions. Toluenesulfonamides, or derivatives
thereof, are used as intermediate for a number of organic synthesis for the
field of pharmaceuticals, pesticides, dyes, pigments, fluorescent brighteners,
resins, and other organic target compound preparations. P-toluenesulphonamide is
used as the precursor of nitrogen-containing crown ethers as designated for the
1,7-dioxa-4,10-diazacyclododecane ring system. Use of p-toluenesulphonamide as a
derivative of ammonia activated to alkylation by alkyl halides is exemplified by
the synthesis of N-tosyl-2,3-dihydroisoindole from o-xylylene dibromide.
Toluenesulfonate esters are useful for the application as alkylating agents in
organic synthesis. |