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Dr:Ahmed

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السلام عليكم(sweat)
ياريت ياجماعه تبقي اجابات فوريه (مش كتب ) لاني عندي امتحان بعد يومين وجزاكم الله خير
1 ايه الفرق بين الdetergent ,surfactant
2ايه الفرق بين ال detergent ,detergent intermediate
3 ما هو ال structure of terylene, debcyl mercaptan
4 هل ال waxزي ال stearic acid مثلا يعني long chain unsat. acids ولاا يه

وفي الختام سلام
 


detergent
A detergent (as a noun) is a material intended to assist cleaning. The term is sometimes used to differentiate between soap and other surfactants used for cleaning. As an adjective pertaining to a substance, it (or "detersive") means "cleaning" or "having cleaning properties"; "detergency" indicates presence or degree of cleaning property.
Contents​





surfactant
Surfactants are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids.
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Terylene - a kind of polyester fabric
Dacron
polyester - any of a large class of synthetic fabrics

trademark - a formally registered symbol identifying the manufacturer or distributor of a product

49257_1212210506.jpg

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Dodecyl mercaptan
Identification
Name
1-Dodecanethiol
Synonyms
Dodecyl mercaptan; Lauryl mercaptanChinese Names
Molecular Structure
112-55-0.gif


Molecular Formula
C12H26S
Molecular Weight
202.40
CAS Registry Number
112-55-0EINECS203-984-1
Properties
Density
0.845
Melting point
-7 ºC
Boiling point
266-283 ºC
Refractive index
1.458-1.46
Flash point
87 ºC​
 


Wax
الشمع مادة دهنية صلبة تستخدم غالبا كغطاء حامي للأسطح المختلفة وكذلك في صناعة الشموع ومواد التلميع والورق المشمع وهو صلب في درجة الحرارة العادية ويذوب بالتسخين .
Wax has traditionally referred to a substance that is secreted by bees (beeswax) and used by them in constructing their honeycombs.
It is an imprecisely defined term generally understood to be a substance with properties similar to beeswax, namely​
Waxes may be natural secretions of plants or animals, artificially produced by purification from natural petroleum or completely synthetic. In addition to beeswax, carnauba (a plant epicuticular wax) and paraffin (a petroleum wax) are commonly encountered waxes which occur naturally. Earwax is an oily substance found in the human ear. Some artificial materials such as silicone wax that exhibit similar properties are also described as wax or waxy.

Commercial honeycomb foundation, made by pressing beeswax between patterned metal rollers.


Contents


1 Wax chemistry

2 Uses of wax

3 Wax types
3.1 Animal waxes
3.2 Vegetable waxes
3.3 Mineral waxes
3.4 Petroleum waxes
3.5 Synthetic waxes
4 References

5 External links

Wax chemistry
Chemically, a wax is a type of lipid that may contain a wide variety of long-chain alkanes, esters, polyesters and hydroxy esters of long-chain primary alcohols and fatty acids. They are usually distinguished from fats by the lack of triglyceride esters of glycerin (propan-1,2,3-triol) and three fatty acids. In addition to the esters that contribute to the high melting point and hardness of carnauba wax, the epicuticular waxes of plants are mixtures of substituted long-chain aliphatichydrocarbons, containing alkanes, fatty acids, primary and secondary alcohols, diols, ketones, aldehydes.[1] Paraffin waxes are hydrocarbons, mixtures of alkanes usually in a homologous series of chain lengths.​
 


Stearic acid
Stearic acid (IUPACsystematic name: octadecanoic acid) is one of the useful types of saturated fatty acids that come from many animal and vegetable fats and oils. It is a waxy solid, and its chemical formula is C18H36O2. Its name comes from the Greek word stéar (genitive: stéatos), which means tallow. The salts and esters of stearic acid are called stearates.
Contents


1 Production

2 Uses

3 Reactions
4 Metabolism
5 See also
6 References

7 External links

Stearic Acid, a Fatty Acid

Stearic acid is an example of a fatty acid. Fatty acids are long molecules consisting of a hydrocarbon chain with a carboxylic acid group (-COOH) at the end. The long tail of the molecule, made up of carbon and hydrogen, is not attracted to water and is said to by hydrophobic (literally, water-fearing). The carboxylic acid "head" can form hydrogen bonds with water, and is therefore strongly attracted to water. It is said to be hydrophilic (literally, water-loving). When a fatty acid is placed on a water surface, the hydrophilic heads of the molecules are attracted to the water. As a result, the molecules form a monolayer on the surface of the water with their heads sticking into the water and their hydrophobic tails sticking up above the surface of the water.
stearic acid, C18H36O2
stearic_full.gif
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Writing out all of those C's and H's in the diagram of the molecule can get tedious. They can also obscure the underlying structure of the molecule. Therefore, a common shorthand is to leave them out. In the following diagram, at the points where line segments join, it is understood that a carbon atom is present with enough hydrogens to make sure all of the carbon bonds are filled.
stearic acid, alternative representation
stearic_backbone.gif
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Polyester
Polyester as the name suggests is made out of esters. Esters are functional group with –COOR, where R is a methyl group. Polyester is a man made fiber, which is a polymer with esters. Polyester is a very popular yarn these days. Popular polyester is called terylene and another name for the terylene fiber is dracon.
Preparation of polyester
We have seen earlier that esters are formed when a carboxylic acid reacts with an alcohol. Polymerization reaction can make the ester formed into long chain molecules.
The following raw materials are used for the manufacture of a polyester called terylene
1))Tetraphthalic acid
2((Ethylene glycol
Tetraphthalic acid is a dicarboxylic acid, that is it has two –COOH groups. It reacts with ethylene glycol that has two –OH groups to give an ethylene type ester. The polymerization reaction gives polyester and water. This particular polyester is called terylene. The reaction is shown below

49257_1212210506.jpg


Molten or viscous terylene molecules are forced through spinneret holes in the form of jets which gives rise to terylene threads.
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عالسرعه والمحتوي
 


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