Day 011 - 12 Jul 94 - Page 38
1
Q. What does that name signify?
2 A. It indicates that they contain what are called
saturated carbon atoms, i.e. They contain as much hydrogen
3 as it is possible to pack around that class of molecule.
This is in comparison, for example, to ethylene or ethane
4 which is known as an unsaturated hydrocarbon, or alkene,
which does not have as many hydrogen atoms as the carbon
5 atom would actually like to bind.
6 Q. We spell alkane, A-L-K-A-N-E.
A. Yes. 'ane' means it is fully saturated.
7
Q. I apologise for pre- 'O' level chemistry, but is it the
8 same sort of indication as we get from nitrite and
nitrate?
9 A. Yes.
10 Q. Are these hydrocarbons what is nowadays called flammable?
A. Yes.
11
Q. Is pentane flammable?
12 A. Yes.
13 Q. Is it very flammable, quite flammable, not very flammable?
A. I would describe it as very flammable.
14
Q. What are the disadvantages, apart from its flammability,
15 of using pentane as a blowing agent?
A. The main disadvantage would be that if it were to
16 leak into the surrounding atmosphere of a plant in low
concentration it will react with the hydroxyl radical in
17 the air and eventually lead to excessive ozone production
near ground level.
18
Q. With what effect for the environment?
19 A. Basically smog production. The best example of that
would be London because there is actually an ozone alert
20 at the moment because in the cities in the South of
England when you have a large amount of sunshine and other
21 alkanes (which in this case are emitted from cars) getting
into the local atmosphere, you get an increase in ground
22 level ozone.
23 Q. Is that bad for people?
A. Yes.
24
Q. Is that is what is called photo-chemical smog?
25 A. Yes.
26 Q. Is it particularly bad just now because we have got a lot
of sunshine and not much wind?
27 A. It is bad at the moment because you have a lot of
sunshine, not much wind, a lot of car emissions and no
28 rain - which otherwise take the chemicals out of the air.
29 Q. Can we assume that on a filthy day in November we will not
get much photo-chemical smog?
30 A. Indeed you can because if you look at the current
distribution in the British Isles you will discover that
