Chenistry Manufacture After The Crash!

[PhDwannabe]

So, this may take a bit to explain:

 

Since I was a kid, I have always loved survivalism, and have been fascinated with how I'd manage to live after some large-scale, more or less civilization-ending event. (You can imagine my teenage disappointment when Y2K passed without incident.) I am committed to reason, science, and progress, and I certainly don't honestly long for the end of civilization--it's less likely I'll live to 500 years and see the mountains of Mars that way. Nonetheless, I have always found planning for "The Crash" to be a great intellectual exercise and pleasantly all-consuming fantasy.

 

My question here is this: suppose civil society was gone (pick your nuclear war/pandemic/zombie scenario). You're living off the land in your little survivalist encampment of a dozen people or so. Suppose you've got some durable but relatively simple lab equipment you got to bank ahead of time, and only the renewable resources that could either be stored in large quantity indefinitely, or an essentially Iron Age society could produce. Some sustainably generated electricity is available (for a few decades, at least, until all of our solar cells and wind turbines break) but things like stored gases wouldn't last long. Temperatures above that which can be produced with charcoal and below that of salty ice aren't possible either, and keeping them stable for certain reactions could be crude. Managing pressures other than atmospheric would also be difficult. Given all these limitations, what sort of useful substances could you make? Of course, the priorities are to create things that would be somehow useful--say, for cleaning, or for medicine. Industrial quantities of reagent grade chemicals would not be possible to produce, but thankfully, they probably wouldn't be necessary either. Many methods would be technically inefficient, at least compared to the cracking of fossil fuels which has produced just about every useful household chemical I can think of for the last half a century at least.

 

Based on my basic knowledge of chemistry, here's the list I've got:

 

Ozone (for water purification if needed): run a corona discharge through oxygen, produced from electrolysis of water.

Charcoal (a thousand purposes): pyrolysis of wood or other vegetable matter.

Potassium nitrate/saltpeter (for combination with charcoal and stored sulfur to make gunpowder): souring and filtration of collected urine.

Potassium hydroxide/potash lye: collected from wood ashes.

Soap, glycerin (hygiene): saponification of animal fats with potassium hydroxide.

Sodium hypochlorite/bleach (sterilization): cooled electrolysis of brine; although I think a Nafion membrane is really needed here--certainly a nonrenewable resource.

Quicklime (nixtamalization of corn, mortuary use, water flocculant): pyrolysis of calcium carbonate, easily obtained from eggshells.

Slaked lime (mortar, hide tanning, food preservation uses): just add water to quicklime.

Ethanol (sterilization, recreation if you're into it): fermentation of about any carbohydrate source, and distillation into a desired strength.

Acetic acid/vinegar (cleaning): acetobacter fermentation of ethanol.

 

You could get by for a while with a kit like that. Some holes in it though--would be nice to be able to make something like hydrogen peroxide, even something like ether for primitive anesthesia. I had a pathway for sulfuric acid, but it involved a vanadium oxide catalyst to get oxygen married up with sulfur dioxide. Something like that is less simple and elegant than we'd prefer, though perhaps necessary sometimes for really useful stuff. And probably a million other things I can't think of. So, I turn it over to the forum: what could you make? Alternately, are any of the above listed wrong, simplistic, or misinformed? Have fun joining me in my odd fantasy!

[Arthur Dent]

A very interesting thread!

 

Given your doomsday scenario, I believe that the ingenosity of some people would ensure their survival. All the building blocks of a "new society" could be salvaged from the remains of the old society. Anything from chemicals, metals, equipment, building materials, could be recycled in some way:

 

Calcium Sulfate could be salvaged from the gypsum panels from old buildings to make plaster of paris, beach sand, with lime and a few additives, can be turned ito cement. Literally millions of tons of plastics could be collected, melted, distilled into various polymers and hydrocarbons. Sea water, when distilled, could provide sea salt, composed of salts of Sodium, Magnesium, Potassium, Calcium... food supplements, vitamins and medication could be harvested from even the simplest vegetation. Old electronic equipment could provide the components for tools and devices, old gas cylinders could be used to make vacuum chambers. The list is endless.

 

A person with a good sense of "McGuiver-ism" could certainly survive even in the harshest of climates. Bear Grylls could certainly give us a few lessons how to keep cool with his pee and build a condo out of dirt and twine, LOL!

 

- Robert

[PhDwannabe]

Of course, the easiest way to get a lot of things would be scavenging--at least in the early years after my hypothetical crash, the good scavengers are probably the winners. (I do very much like the idea of the drywall gypsum harvest in particular.) For whatever reason, though, my fantasy seems to be of a sort of stationary stronghold out in the relative wilderness, where contact with others could not always be counted on as reliable. Scavenging would be limited to the immediate environs, and might be exhausted fairly quickly. I like the idea of planning for the absolute indefinite.

 

Also, of course, many things can be harvested and used without much processing. You don't need to synthesize pyrethrins for pest repellent, because you can just grow chrysanthemums and crush them.

 

So, smart harvesting and use of natural substances for all kinds of purposes is one thing--you'd be surprised, by the way, how difficult it is to get decent information on this. (The moonbats who post on survivalist websites do not tend to be, uhhh... real sold on the scientific method.) Beyond all this, though, I do wonder what else one could do and make with their end-of-civilization chemistry set. Any ideas?

[Mr Skeptic]

Hm, this is somewhat similar to one of my fantasies of being transported a few thousand years into the past, although I focused more on machines because I don't know enough chemistry.

 

One of the important things to have is a distiller, to distill certain of the items you mentioned.

 

You'll also want some of the strong acids.

Sulfuric acid: burning sulfur to get sulfur dioxide, oxidizing it some more (with an optional platinum or vanadium(V) oxide catalyst), and adding water.

Nitric acid: You can make it from your saltpeter and sulfuric acid, or oxidizing ammonia and adding water, or if you have the energy to waste, zapping air and adding water.

Hydrochloric acid: salt and sulfuric acid.

 

Oh, and you may want ammonia for fertilizer and chemical feedstocks too.

[PhDwannabe]

Yeah, ammonia would be nice, but I know of no way to produce it in any way besides cracking fossil fuels. The Hive Mind says something about dry distillation of animal dung. Although you wouldn't necessarily need it for fertilizer--if you manage compost piles well and keep crops and garden beds rotated, you can keep that nitrogen conveyer moving nicely without needing your chemistry set. It'd still be nice to have it, as you say, for chemical feedstock to make other things (though I'm not sure quite yet what other things...)