Symphony in C by Robert M. Hazen

Author:Robert M. Hazen
Language: eng
Format: epub
Publisher: W. W. Norton & Company
Published: 2019-04-11T16:00:00+00:00

SCHERZO—Useful Stuff

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Fire! Fire is the key to refining coal and oil, themselves rich remains of buried life baked and compressed into complex mixtures of countless thousands of different molecules.5 Most molecular ingredients are small, familiar hydrocarbon fuels: methane, ethane, propane, octane. Many others are large, complex molecules boasting dozens of carbon atoms with crucial bonds to oxygen, nitrogen, sulfur, and other elements.

The trick to refining is heating this smelly, black chemical stew in a tall, segmented cylinder, much hotter at the bottom than at the top. You see these distinctive “distillation columns” every time you drive by chemical facilities with their bristling ranks of towering metal tubes, some flaming at their tops as they burn off small amounts of excess methane—a trivial quantity of natural gas that chemical engineers deem too meager to collect for profit. Each of those towers performs multiple steps in the chemical separation process.

As the mixture of ingredients is heated in the column, each molecular component reaches its boiling point at a different height. A complex system of pipes juts off of the column at successive levels—each pipe drawing away and collecting a different product, thus distilling the complex, black liquid in stages. Smaller molecules generally boil at lower temperatures, and thus they emerge from stages higher up in the column—propane and butane near the cooler top, gasoline and kerosene in the middle, with thick, sticky liquid asphalt and waxes flowing out of the hotter bottom. Refineries link their distillation columns in a carefully choreographed chemical dance, with each column accomplishing some phase of the essential task of selecting and concentrating critical organic chemicals.

Once those diverse carbon-based molecules are distilled and purified, chemical tricks to produce new compounds abound: mix varied chemicals in large vats and retorts, stir them, squeeze them, add just the right reactive ingredients, perhaps add a pinch of catalyst, then cook at just the right temperature. Diverse recipes yield cookbooks full of useful synthetic products. Among the most important materials for modern life are polymers—plastics with nicknames like PETE and PVC, the synthetic fibers nylon and rayon, paints, glues, rubber, and hundreds of other chemicals that play innumerable roles in our lives.

All of these materials feature countless small molecules linking end to end to form long chains with carbon backbones. Life, too, has learned these chemical tricks: skin, hair, muscle, tendons, and ligaments—all are biopolymers. The same is true with leaves and stems, roots and wood, filaments of algae and strands of spider silk. Clever chemical manipulations also yield myriad carbon-based compounds, such as waxes and resins, fats and oils, lubricants and glues, cosmetics and drugs.

Check out the nutrition label on your favorite snack food. Everything we eat is rich in carbon-based molecules: amino acids, the building blocks of protein; lipids, the components of fats and oils; carbohydrates, including sugar, starch, and dietary fiber. Carbon provides the carbonated fizz of soda, and the alcoholic buzz of booze.

Let’s explore some of the properties of carbon compounds that make them so indispensable to everyday life.

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