h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Manmade ones that is

I have a bottle of sodium sulphide (for lead paint testing). How was it made?

Some other examples that might help me understand better:

- baking soda (sodium bicarbonate)

- vitamin c (in a multi-vitamin tablet)

- penicillin (semi-synthetic)

Or any other examples you can think of.

I mean how are they made in practical terms, not chemistry formulas.

Ummm, carefully?

I expect someone like SoRB can answer this to many levels of detail, and am curious myself.

Well this is such a wide ranging question that I shall only attempt to answer the ones specified. I also assume you mean industrially as opposed to the laboratory where there tend to many, many ways of making things.

Sodium sulfide is made from sodium sulfate by reducing it with carbon in the form of coal.
(reducing something is the opposite of oxidising - hence you remove oxygen from sulfate to form sulfide - the carbon is in turn oxidised in this process to carbon dioxide).

Sodium sulfate is generally mined but can be made synthetically as a by-product of other processes.

Sodium bicarbonate is a mineral and will just be mined - there are synthetic approaches to it but it isn't all that large scale as far as I can tell (Well 100,000 tonnes a year doesn't seem all that much - compare that to ammonia production or that of petroleum derivatives...).

The most common synthetic approach is to use a process called the solvay process where calcium carbonate, sodium chloride, ammonia and CO2 are reacted in water. The sodium bicarbonate precipitates our of solution when it reaches a sufficient concentration and can then be dried.

I looked those up on wikipedia by the way, not that hard to do and not really very interesting compounds to make, hence why I didn't really know in advance.

The last two are cool as I teach these to Masters students.

Synthetic Vitamin C is famously made by a synthetic process called the Reichstein process.

D-Glucose (naturally sourced) is reacted with hydrogen in another reduction reaction to produce D-sorbitol.
Sorbitol is then oxidised to L-sorbose using a bacterium called acetobacter (various species of this can be used).

The L-sorbose is then oxidised over a platinum catalyst - the product of this dehydrates and you have your ascorbic acid (vitamin C).


Semi-synthetic penicillins are all made from a compound called 6-amino-penicillinic acid (6-APA).

6-APA is made by fermentation - you just grow up a lot of mould (various penicillium species are used depending on which antibiotic you wish to make) which produces natural penicillins with side chains that are generally not useful. Hence you cleave off this side chain using a biological catalyst (enzyme) called penicillin acylase.

We then go off an make a useful side chain in a chemical synthesis plant. There are so many that there is no space to go through them all here and there are also many ways of making them.

The 6-APA and the useful side chain are coupled together, again using chemical synthesis in a plant. Not so many ways of making them - usually it involves creation of something called an amide bond between an amino group (NH2) of the 6-APA and a carboxylic acid (-CO2H) of the synthetic side chain.



Not sure if that is what you wanted but there it is.

Sodium sulphide is made by the reduction of sodium sulphate by heating it with carbon (ie. charcoal). Sodium sulphate, rather conveniently, is a by-product of hydrochloric acid production.

Bicarbonate of soda can be made in a number of ways. Industrially it is made through the Solvay process, which uses ammonium carbonate as an intermediate. Basically, it involves bubbling ammonia and carbon dioxide through concentrated salt solutions, and is practical for chemical engineering because it is easy to regulate as a continuous process (as opposed to batch mproduction). On a small scale, you can make sodium carbonate by heating sodium chloride with sulphuric acid.

Penicillin and Vitamin C really do require chemical formulae to show you how they are made. Like all organic chemicals, they require a multi-stage process, along with protracted methods of separation and purification.

B

That was a simulpost, of course...

B

And, as an interesting side-game, let's play 'spot the organic chemist and the inorganic chemist'

B

http://chemistry.health-tips-diseases.com/2010/09/sodium-sulfide.html

In my experience in the chemical industry, relatively little of the equipment or energy on any chemical plant is used in the process that actually turns raw materials into products. Most of the effort goes into

(a) purifying and preparing the raw materials for the reaction
(b) separating the product from by-products and wastes and purifying it and preparing it to a point where it's in a saleable form and
(c) dealing with the separated by-products wastes

>Sodium sulfide is an organic chemical<

Well seeing as the definition of an organic chemical is one that contains carbon...

Hello Kea?

Do you cook? If so then you have already done a great deal of chemistry. For example, the caramelisation reaction (browning of sugar) and the Maillard reaction (reaction between sugar and protein units)

http://en.wikipedia.org/wiki/Caramelization
http://en.wikipedia.org/wiki/Maillard_reaction

S.A.