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Tuesday, 28 October 2014

Home Chemistry and Explosives Precursors

Tasker Dunham’s chemistry set boosted his school science marks, but how easy is home chemistry today?

Without anyone really noticing, new regulations relating to the “supply of explosives precursors” have recently been introduced in Britain. From September, 2014, you need a Home Office licence to buy chemicals that could be used in the illicit manufacture of explosives. From March, 2016, you need a licence simply to possess them. The list includes potassium chlorate, sodium chlorate, hydrogen peroxide and nitric acid. The licence also covers a number of poisons, including mercury, and there is a further secondary list of reportable substances for which any suspicious transactions or thefts must be reported. This includes sulphuric acid, acetone, and ammonium, sodium, calcium and potassium nitrates.

What strikes me most of all about these regulations, is that these are chemicals of interest to the home scientist. I used to have several in my childhood chemistry set. It seems we now need a licence to pursue an innocent educational interest. The licence costs £39.50 and must be renewed every three years. Children under eighteen will only be granted a licence in exceptional circumstances subject to additional conditions requiring adult supervision. See the web site for the official guidance.

Do these regulations really prevent terrorists from making explosives, or do they just make things unnecessarily difficult for innocent members of the public? I would have thought any chemist worthy of the name would easily be able to make or extract any chemical they need from sources such as weed killer, fertiliser, bleach and drain cleaner. It used to be common knowledge that if you wanted to make a bang, you just mixed sugar with weed killer, taking care not to blind yourself or blow your hands off. You can't have your hands sewn back on if you can't pick them up to take them to the hospital.

I have some concentrated acetone in my garage, a half-full nineteen-eighties bottle of nail varnish remover. It was my mother’s, but I kept it because acetone is useful as a solvent for removing sticky marks and so on, and as well as that, it's nice to have a quick sniff now and again. Am I in danger of being arrested for terrorism if I fail to take proper care of it?

Kay Chemistry Set 1960s

My Kay chemistry set was one of the best Christmas presents I ever had. I had drooled over it in the toy shop window for months. It had an array of exciting chemicals in stoppered glass test tubes: blue and green sulphates (sometimes irritatingly now spelt with an ‘f’, which just looks wrong) , purple needles of potassium permanganate, white powders, silver-grey chunks of zinc and glittering grey-brown iron filings. Its apparatus included further test tubes, a teat pipette and a round bottomed flask, together with litmus paper, a plastic funnel and filter papers. There was a stand to keep the test tubes upright, and a device to hold them as they were heated in the flame of a methylated spirit burner standing on a heat-resistant asbestos mat. There was a booklet of experiments, ‘The Wonders of Chemistry, prepared for the young experimenter by an experienced science master.”

The experiments in the booklet were interesting enough to begin with: growing differently shaped crystals from hot saturated solutions as they cooled – most memorably the bright blue diamond gemstones of copper sulphate; turning litmus paper from red to blue in alkalis, and blue to red in acids; mixing brown ‘logwood chips’ with alum to extract a vivid blue-purple natural dye. It was even possible to make small quantities of oxygen, carbon dioxide and hydrogen gas, but not enough to match the fabulous wizardry of some of the things we did in chemistry at school. Let’s face it, you don’t just want a chemistry set to grow crystals and change colours, you want to make invisible ink, smoke bombs, poisons, evil smells and explosions.

F Sherwood Taylor: The Young Chemist

I got hold of a better book, ‘The Young Chemist’ by F. Sherwood Taylor, which is not easy to find these days but my ragged copy remains in my bookcase. It was great. There were new experiments which, the dust jacket claimed, “… can be carried out at home cheaply, easily and without danger.” Looking at the contents now one has to question the absence of danger. There are sections on gases: carbon dioxide, oxygen, ammonia, hydrogen sulphide, chlorine; sections on acids: sulphuric, hydrochloric, nitric; and sections on various other substances: sulphur, caustic soda, iodine. But any nagging concerns were clearly unfounded because, as the dust jacket reassured, “… it [the book] has been ‘vetted’ by the Home Office.”

Most experiments in ‘The Young Chemist’ needed additional equipment - a Bunsen burner and a crucible - and additional chemicals. “Real iodine,” it says to distinguish it from tincture of iodine, “is a black shiny solid. Ordinary chemists stock it, and it costs 2s 4d an ounce. A quarter of an ounce will do for quite a number of experiments.” It seems unlikely that if you walked into your local branch of Boots today and asked for thirty grams of elemental iodine you would be very successful. In America you have to have Drug Enforcement Agency authorisation to buy iodine or its compounds because of its use in the clandestine manufacture of methamphetamines such as ‘crystal meth’.

But in those days, buying chemicals really was as straightforward as the book made out. My dad called at the chemists and came home with bottle of hydrochloric acid, in a hexagonal emerald-green poison bottle. That same bottle, empty, was still on a ledge at the back of his shed when I cleared it out forty years later. We mixed the acid with zinc to produce hydrogen gas which went pop to a match flame held at the mouth of the test tube. ‘The Young Chemist’ goes on to show how to make enough hydrogen to fill a balloon, but I could never get a seal tight enough not to leak.

Safely guided by the book, I made free chlorine gas from hydrochloric acid and bleaching powder. “It is not wise to make any considerable quantity of chlorine,” it warns, “but it is quite safe to make small quantities and use them at once, if care is taken not to let the gas escape.” So I carefully made just a small quantity of the greenish-yellow gas in a test tube, and was curious to know what it really smelled like. Having previously sniffed a tube of ammonia I’d made by heating ammonium carbonate, and lived to tell the tale, I felt sure the warning could be ignored. Maybe if I had reflected on the fact that my fascination with chlorine stemmed from its use as a chemical weapon during the First World War, I might have been a bit more sensible. Even a cautious sniff had me coughing and reeling with a burning pain inside my nose.

The book explains how to ferment glucose and distil alcohol, which it acknowledges as illegal, but “… as long as the alcohol is not drunk or sold it is unlikely that the excise authorities would object.”

Even the humble Bunsen burner had its potential dangers. Nineteen sixties houses had brass gas taps emerging through the floorboards beside the hearth for the purpose of supplying gas through a rubber tube to a free standing gas fire. As mains gas appliances now have to be permanently plumbed in by ‘Gas Safe’ engineers with all the right up-to-date certificates, gas taps and free standing gas fires that burn mains gas must now be illegal. I haven’t seen a domestic gas tap for years, yet all seemed perfectly safe at the time. You simply needed to be aware of the dangers. Everyone knew the fires gave off noxious fumes, caused terrible condensation and were easily knocked over, and that gas taps could be turned on by curious children wanting to know what happens when you fill a room with gas, which in those days was poisonous coal gas rather than the less toxic North Sea gas. So we were very careful. It seemed entirely natural to run a gas supply to my Bunsen burner through a long rubber tube, around ten yards in length, from the gas tap, across the room, out through a partly open window and then a short distance across the yard to my ‘laboratory’ in the shed. What could possibly go wrong?

Bunsen burners mixed gas with air so, unlike methylated spirit burners, they were hot enough to melt glass. ‘The Young Chemist’ shows how to bend tubes and blow glass bulbs. I only burnt myself once.

Today, the book’s claim to be without danger might not stand up litigious scrutiny, and the Home Office would be unlikely to ‘vet’ it so leniently. Perhaps this is why some of the cheaper chemistry sets now, especially for children under twelve, seem particularly feeble compared to sets from the nineteen sixties. Some are so safe they have only plastic test tubes and no glass, substances ‘warmed’ by immersion in hot water because there are no flames, and the biggest deficiency of all, no actual chemicals, or at least nothing you can’t eat. The bleaches and disinfectants under the kitchen sink are more dangerous and more poisonous than the contents of these so-called chemistry sets. Some sets contain only materials such as balloons, clay and starch, with serious warnings to handle them carefully. The largest and most prominent item is often a pair of safety goggles. Woe betide anyone who blows up a balloon without wearing safety goggles!

In America, things are even worse. In some schools, science teachers have to sign out ‘dangerous’ substances like vinegar and baking powder from locked cupboards. This, in a country where guns and ammunition are freely available! You even need a criminal background check to buy laboratory glassware. Coffee machines contain three items that would violate the drugs agency regulations if found in a home laboratory: a filter funnel, a Pyrex beaker and a heating element. There are reports of innocent home chemicals suppliers being raided by police under the Federal Hazardous Substances Act, accused of supplying banned substances such as sulphur and potassium nitrate which might be used to make illegal fireworks.

The most expensive chemistry sets now available, costing over £150 (such as Brightminds Chemlab 3000), do still seem to measure up to the old sets in terms of apparatus, but you have to obtain many of the chemicals yourself, especially anything liquid, such as meths for the burner, sodium hydroxide, ammonia solution, hydrochloric acid and silver nitrate solution. The internet now makes these easier to find, but safety and regulation still take precedence over interest. And £150 might be more than most families would be willing to pay, especially if a £39.50 licence is required as well.

It is all a far cry from my school science days, when bottles of sulphuric acid were always on the benches, we rounded up droplets of mercury spilled on the floor by the previous class, and wafted large asbestos mats at each other. One wonders how children are supposed to gain confidence in the handling of hazardous substances and with other risks, when chemistry sets are so bland, ineffectual and uninteresting. I was dismayed to see my own children’s uneasy clumsiness in trying to strike matches to light a candle.

One also has to wonder whether the hands-off passivity of demonstrations, videos and simulations, enthuses as much interest in science as running experiments first hand. My own chemistry set, at least for a time, boosted my school marks, and although in my case these interests later waned, there are many professional scientists who fondly remember how their careers developed out of a passion for carrying out experiments at home. It isn’t right to impose too many restrictions on these things.

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