How Does Thioglycolate Hair Remover Work?

Biology, Chemistry
Hair: men bemoan its loss and women fret over its appearance. For decades during the 20th Century, women were enamored by the so-called permanent wave. The most common process for assuring permanency of a hairstyle obtained at the beauty parlor involved a chemical process involving thioglycolate. See, Permanent Wave: Chem-mystery of Curl. By Extension... Although this process was used, not to remove hair, but to beautify it, by extension, a closely related process has been used to eliminate hair that grows¹ in undesired places. Notice this chemical reaction that occurs when thioglycolate is used to remove hair². 2 HOOC-CH₂-SH + R-S-S-R → HOOC-CH₂-S-S-CH₂-COOH + 2 R-SH The above reaction reads: two thioglycolic acid molecules plus one cystine (disulfide hair bond) produces two dithioglycolic acid molecules and two cysteine molecules. To…
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Manufacturing Polyurethane Involves Diisocyanates: How Dangerous?

Chemistry, Health
You almost can't escape from it. In one form or other, it is nearly everywhere. What is that? Polyurethane. We will focus on polyurethane in furniture refinishing. Then we will discuss its manufacture, and how its manufacture is so dangerous. Furniture Refinishing Before Polyurethane When I was young, I assisted my father in refinishing furniture. First, we'd strip the old finish off. Then, we'd rub the piece with fine very sandpaper. But that wasn't good enough. So we followed that up by polishing the surface with clean, dry, soap-less steel wool. Next, we'd apply a choice stain with a cotton rag such as an old torn T-shirt. Once that dried, we'd apply a coating of shellac. Once that was completely dry, we varnished. However, a coating of varnish produced to…
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Motor Oil Degradation in Automotive Engines

Chemistry, Technology
Why is it so important to change the motor oil in your car? The answer is due to motor oil degradation. Unrecycled motor oils originate from naturally occurring crude oil. As such, motor oils are necessarily a complex combination of organic compounds: Molecules made simply of carbon and hydrogen. A percentage of these hydrocarbons include ring structures—whether saturated aliphatic rings or aromatic rings (benzene or polycyclic). However, the largest percentage of motor engine oil consists of straight and branched chain hydrocarbons of varying lengths. Motor oils are high-quality lubricants, but even the best of these products will degrade with use. Why is Oil a Lubricant? A good lubricant must readily flow and have sufficient viscosity. It should not freeze in even cold environments. It should possess a high level of…
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Sulfur Analogs of Oxygen-Containing Organic Compounds

Chemistry
[caption id="attachment_24653" align="alignright" width="480"] Common oxygen-containing organic compounds[/caption] Organic compounds contain carbon and hydrogen, and occasionally other elements. Most notably, these include nitrogen and sulfur, but also phosphorous, chlorine, bromine, and iodine. Simple oxygen-containing organics, including n-butyl alcohol, benzaldehyde, methyl ethyl ketone, diethyl ether, and tert-butyl peroxide appear in the illustration at top. An analog is a structure which is similar to another structure, except that one atom or group is replaced by another (similar-behaving) atom or group. Here, we will discuss sulfur analogs. Alcohols The generic structure for a simple hydrocarbon, a compound of hydrogen and carbon, is usually written RH. The equivalent for an aromatic structure is ArH. An alcohol has one hydrogen atom replaced by an –OH group. Hence, an alcohol is written generically, R–OH. The aromatic…
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Electronegativity of Atoms: What are Determining Factors

Chemistry, Physics
[caption id="attachment_24637" align="alignright" width="480"] 5d molecular orbital - Image Dhatfield[/caption] When two different types of atom are bonded together, they do not share their bond electrons equally. This is because each type of atom possesses its own charge environment, which results in an atom’s electronegativity. Electronegativity is the measure of an atom’s ability to attract additional electron density to itself. For example, Sodium seeks to give an electron to become a positive ion, Na+. It has a very low electronegativity. Iodine wants to gain an electron to become a negative ion, I-. It has a relatively high electronegativity. Charge Environment Atoms vary in electronegativity, and bonds vary according to constituent atom electronegativities. The electronegativity of an atom depends upon its charge environment. That environment depends primarily on three things... Distance…
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From Acids to Superacids: From Lavoisier to Olah

Chemistry, History
Acid theory evolved in stages. Our understanding of what constitutes an acid has improved, but that is not all. As a result of our better understanding, acids of greatly increased strength – superacids – have become available, as well. Early Acid Theory – Lavoisier [caption id="attachment_24574" align="alignleft" width="240"] Lavoisier & wife[/caption] The 18th century French chemist, Antoine Laurent Lavoisier, later guillotined by French revolutionaries, developed a theory of acids inaccurately based on a required presence of oxygen. This theory lasted into the 19th century. Its popular downfall was prompted by its undue restrictions on what constitutes an acid. Many acids contain no oxygen whatsoever. Hydrogen and Acids – Baron Justus von Liebig [caption id="attachment_24577" align="alignright" width="240"] Leibig[/caption] Although there was no detailed theory, credit should be given to Justus von…
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Differences Between Bound and Unbound Electrons

Chemistry, Physics
Atoms are constructed of a central nucleus, containing positively-charged protons and uncharged neutrons, plus orbiting, negatively-charged electrons, in number equal to the number of protons. Although an electron carries a charge equivalent (though of opposite polarity) to that of a proton, its mass is a mere 1/1836th that of a proton. Some mistakenly think the electron isn’t a particle at all, but a cloud. This inaccurate notion doubtless arises from the cloud-like appearance of the probability distribution curve of an electron in its orbit. At any rate, an electron generally exhibits particle-like properties, and is best mentally envisioned as a particle. How the particle we call an electron behaves depends upon the condition in which we find it. There are important differences between bound and unbound electrons. [sc name="MidArticleAdsense"] The…
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Gutta Percha: From Underwater Cables to Golf Balls to Dental Work

Chemistry, History
[caption id="attachment_24465" align="alignright" width="340"] From the 1851 book: Gutta Percha, Its Discovery, History, and Manifold Uses[/caption] Gutta percha thermoplastic¹ is a tough and leathery resinous produced from the milky fluid tapped from certain trees. Isoprene is an extremely important building block widespread in nature. The main component of gutta percha is, in fact, the trans-1,4-isomer of polyisoprene. The cis-1,4,-isomer is, interestingly enough, the primary constituent of natural rubber. It is produced from the milky fluid tapped from "other" trees. The reason for the considerable difference in physical characteristics between rubber and gutta percha (or, rather the trans and cis isomers of polypropylene) is the greater crystalline character of the trans isomer. Notice the difference between the trans and cis isomers in Image 2. How do these isomers differ? Synthesis from…
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Limonene Citrus Cleaner Chemistry

Chemistry
[caption id="attachment_24444" align="alignright" width="480"] A juicy wedge o' lemon.[/caption] Citrus fruits offer both pronounced flavor and pungent aroma. Where does the pungency come from? From the terpene limonene – more specifically, the dextrorotatory enantiomer¹, d-limonene. Although modern terminology is switching from (D)extro and L(evo) notation to S(inister) and R(ectus), we’ve chosen the older terminology, more often associated with limonene. What is Limonene? Limonene is useful commercially in environmentally-safe cleaning formulations, as a solvent, and as raw material in the synthesis of other chemicals, such as carvone. This chemical is also useful as an insecticide and for assorted other purposes. Manufacturers separate limonene from the fruit’s peel by means of steam distillation, or a centrifugal process. Lab Synthesis of Limonene Citrus Cleaner from Isoprene Labs can prepare limonene (a mixture of…
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Chemical Separation by Fractional Distillation and Crystallization

Chemistry
[caption id="attachment_24415" align="alignright" width="480"] Distillation apparatus[/caption] Solids may be subdivided into amorphous solids and crystalline solids. Amorphous solids possess limited order in the way molecules are bonded to each other. Crystalline solids, on the other hand, exhibit an exceptional degree of order. Logic should tell us a mixture of crystalline solids should be capable of chemical separation and purification through some reiterative crystallization process, based on relative solubilities. This proves to be true. The process is called fractional crystallization. Before discussing fractional crystallization, it might prove wise to discuss the simpler process of fractional distillation, the separating by distilling of a mixture of liquids possessing markedly different boiling points. Ordinary Distillation Consider an example of two liquids, Component A and Component B, that are miscible (they dissolve completely one within…
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