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Applied Chemistry books |
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Applied Chemistry books |
These days most of the excitement in organic chemistry is in synthesizing bigger and more complex molecules. Yet most of the economic value is on the other extreme: over 51 billion pounds of ethylene, the most important olefin used in petrochemicals, are produced every year in the USA (the next three, in case you're interested, are propylene, butadiene, and isoprene). That enormous scale means that exotic reagents and complex synthetic schemes are out of the question.
All petrochemicals start out as reduced hydrocarbons, mostly saturated alkanes and aromatics. Regardless of whether their destination is chemicals or fuel, the alkanes are subjected to cracking (adding a double bond) or reforming (aromatization, isomerization, hydrocracking, or hydroalkylation) to improve their octane rating or make them chemically reactive. Both cracking and reforming are catalyzed reactions. This means the sulfur and metal contaminants have to be removed to avoid poisoning the catalyst.
There are enormous engineering challenges involved in handling such large volumes of chemicals. What might need a paper towel when a reaction goes out of control in the lab may require a fleet of ambulances in a petrochemical plant. Here there are no photos but many tables and flow diagrams that describe the processes.
To get a sense of the scale and complexity of the oil refining industry, I recommend Meyers' Handbook of Petroleum Refining Processes (4th ed. due out this July) instead. But you cannot understand those processes without knowing the chemistry, which tells you why those magnificent refineries were built in the first place.
Most of the reactions here are simple carbocation or free radical reactions.
But even so there are surprises. One is the metathesis of olefins, where
propylene, 2-butene, and ethylene can be interconverted at will:
CH3CH=CHCH3 + CH2=CH2⇌
2CH3CH=CH2. A similar reaction is disproportionation
of toluene, where toluene at 450–530°C and 20 atmospheres in the
presence of CoO-MoO3 on ZSM-5 zeolite catalyst is in
equilibrium with benzene and xylenes.
This book ain't Shakespeare, and in some places the list of chemicals and reactions starts to read like an encyclopedia. But ... oh, who am I kidding, this book is dull. Even so, after reading it you'll know what we do with all those 27.5 billion pounds of propylene that we synthesize each year. You might not impress many chicks with that bit of knowledge, but it's important.
feb 27, 2016
What is the most important chemical reaction? Steven Farmer says it's the Haber process N2 + 3H2 → 2NH3, which is used to make fertilizer. Without it, half the ice-free land mass on Earth would be needed to grow food instead of 15%, and 40% of the people on Earth would starve. It's estimated that 80% of the nitrogen in your body was produced artificially through the Haber process.
That's one of the bedtime stories you could tell your children after reading this fascinating book. Farmer is a chemistry professor at Sonoma State University, and discovered that telling his students useful information like this once in a while kept them interested.
Another story is why withdrawal from alcohol addiction causes death. Alcohol mimics GABA, a neurotransmitter which exerts a tranquilizing effect on neurons. Over time, the cells adapt to the sedative effect by producing more excitatory signals. If alcohol is withdrawn, a person can have hallucinations and deadly seizures. The mortality rate of a person in delirium tremens, as the hallucinations are called, is 5%–25%, so a person undergoing alcohol withdrawal has a good chance of dying.
Other stories are about how common products can cause death if ingested. Artist Andy Warhol died from water intoxication after being overloaded with fluids in the hospital. People have gone to prison for giving Visine or Ben-Gay, which are poisonous, to their friends as a “prank.” In fact, drinking pure wintergreen oil (aka methyl salicylate), one of the ingredients in Ben-Gay, was once a common way of committing suicide. It didn't take much.
Why does touching a coin produce a metallic smell? Why would lightning appear orange on Jupiter? Where does the caffeine in Diet Coke come from? Why is Teflon slippery? Why is it impossible to toast gluten-free bread? It's in the book.
This book's a bit overpriced for its market. Professional biochemists and medicinal chemists would know most of this stuff already, and students are not going to pay 55 bucks for a book. That's a shame. It's written in layman's terms, and almost anyone would get something out of it. In our chemical- and drug-filled world knowing this stuff can save your life. More importantly, it could get people interested in chemistry . . . and maybe even biochemistry . . . and inorganic . . . .
Watch for this stuff to show up on TV some day.
jul 22, 2017