Everything is made from oil and gas. Or not?

I regularly come across the opinion that, they say, all industrial products in the world are made from oil and gas, there is no alternative. To the point that without gas and fertilizer it is impossible to make, and even steel cannot be smelted. They especially like to put pressure on this in political disputes. I am categorically not satisfied with the categorical nature of these statements, so let’s figure out whether this is true and how uncontested oil and gas are in certain industrial processes. There will be no proofs, because I’m stupidly lazy, but I will only use open and easy-to-Google information, most of which you will find on Wikipedia. And I’m also a chemist, so I’ll push with authority, that’s it.

Disclaimer: it is obvious that alternative processes are alternative because they are more expensive than the main ones, so their use will lead to higher prices for products, otherwise everyone would have switched to them long ago. But we must understand that the “more expensive-cheaper” relationship has developed at current prices and the availability of raw materials; if these inputs change, the economics of these processes can change greatly. And yet, we must understand that if these methods were actually used in industry in the foreseeable past, then their cost is comparable to current ones.

Basic substances

The top 10 heaviest substances in the global chemical industry include sulfuric acid, ammonia, nitric acid, ethylene, propylene, chlorine, caustic soda, soda, benzene and acetic acid. Each of these substances is produced in the millions of tons and is used in a variety of industrial chemistry processes. The synthesis of each of these substances deserves a separate description.

Sulfuric acid. Everything is clear here, we burn the sulfur until it melts, and then the ends are in the water. The process itself is exothermic, so there is little energy expenditure; rather, the question is how to remove this energy. The synthesis of sulfuric acid has nothing to do with oil and gas. But for petrochemical chemistry, sulfuric acid is sometimes needed.

Ammonia. Hydrogen and nitrogen. And then we either heat it up or throw lightning. In general, despite the fact that the process is exothermic, it consumes quite a lot of energy. But, again, any energy, the source is unimportant. However, a few words about hydrogen. It is not included in the top tonnage products, although if you count not by weight, but by volume, it can even overtake sulfuric acid. The main production method is reforming/pyrolysis of methane or cracking of heavier hydrocarbons. However, there is also electrolysis, it is quite large-scale, but for now it is 1.5-2 times more expensive (depending on the input in a particular location). But electrolytic production of hydrogen is a good option for smoothing out fluctuations in alternative generation, so not everything is so simple. If gas becomes more expensive, say, one and a half times, electrolysis will be able to compete.

Nitric acid. We burn ammonia, and then, characteristically, we push nitric oxide into the water. You need ammonia and some energy. But not at all as much as for the same hydrogen.

Ethylene, propylene, benzene. Mainly needed for the synthesis of polymers and paints. The main source of these substances is now petrochemicals, but there are economically comparable alternatives in the form of coal chemistry through the methanol process, as well as ethanol dehydration (for ethylene). That is, in principle, if there is no oil, these polymers can be made in sufficient quantities from coal and alcohol, but it will be more expensive. But it’s difficult to work with benzene without oil or gas; there are no real industrial processes. In the future, it is possible to boost the catalytic trimerization of acetylene, but for now there is no need.

Chlorine, caustic soda and soda. Obtained by electrolysis of table salt. We need electricity, it makes no difference whether it came from a thermal power plant, a nuclear power plant or a wind turbine. Caustic soda is still obtained in some places through the Solvay process, from slaked lime, but its share is steadily decreasing. In general, this industry also does well without oil and gas, just like soda, which is produced from the same table salt using carbon dioxide and either lime or ammonia.

Acetic acid is produced either from methanol or from bio-based materials. Since we’re talking about methanol, let’s talk about how it is synthesized, and at the same time formaldehyde, especially since when steamed they even exceed vinegar in production volume. Methanol is not produced from oil and gas at all; it is made either from coal or from bio-raw materials. and formaldehyde, accordingly, is obtained from methanol.

Suddenly, out of the 10 largest tonnage products of the chemical industry, only three are related to petrochemicals, and even one of them can be produced without oil. The largest share in the cost of these substances is energy. In addition, capital investments and logistics costs are very high.

Polymers.

Next we will have polymers, because this is the largest-capacity product of the chemical industry, surpassing even sulfuric acid in production. In first place among the produced polymers are polyethylene and polypropylene, produced from ethylene and propylene, respectively, the production of which we discussed above.

Following them are PVC and polystyrene. These two polymers in general are somewhat losing their positions in the global polymer industry, but are still in the top 5 most tonnage ones. PVC is made from vinyl chloride, which in turn is made through a series of transformations from ethylene or acetylene. We already know how ethylene is made, but acetylene appears. Acetylene can be produced by pyrolysis of gas or petroleum products, but it can also be produced by coal chemistry, through the carbide process. And the carbide process is quite used in industry these days. Polystyrene is obtained from styrene, which is made by the oxidation of ethylbenzene, which is obtained either as a by-product of catalytic reforming, or from benzene and, therefore, ethylene. We've already looked into benzene, and so far everything is quiet – only oil, only hardcore.

Rounding out our top five is PET, which is synthesized from ethylene glycol and terephthalic acid (or its esters). Ethylene glycol is synthesized from ethylene, but there is also a significant part of the coal chemical process. Terephthalk is produced from n-xylene, which is also obtained by catalytic reforming of oil. But, there is a big but! Unlike previous characters, PET is a realistically and economically feasible chemically recyclable polymer, and terephthalic acid can be completely extracted from recycled PET and put back into synthesis, like ethylene glycol. Therefore, if necessary, the need for a new monomer can be reduced several times.

Next come polyamide, polycarbonate and polyacrylates/acrylamides (combined because their monomers are made from the same precursors). Polyamide is ultimately made from benzene through a bunch of steps, and you already know about benzene. Polycarbonate is made from bisphenol A, which ultimately rests on the same benzene. Methacrylates are obtained from acetone, which can be obtained from bio-based materials (even a person, although not very healthy, can generate acetone). This process occupies a small share in the world production of acetone, but it is alive, i.e. has at least a comparable cost.

The current state of affairs is such that the synthesis of polymers depends mainly on oil/gas chemistry. Most of it can be replaced by coal chemistry, some by the chemistry of plant raw materials, but at the cost of a rather painful restructuring of large-scale processes and an inevitable rise in price, for some polymers – a multiple. Well, you need to understand that coal chemistry requires more energy per unit of production than petrochemicals.

Solvents

Various small organic molecules, mostly liquid, which are not monomers for the synthesis of polymers. These are mainly solvents, plus some precursors for the synthesis of polymers, as well as paints, adhesives, etc. Unfortunately, I couldn’t quickly find statistics on global production volumes, so I’ll just go through the main families.

Hydrocarbon solvents. Aliphatic ones, in addition to petrochemicals, are quite produced using coal chemicals. It’s more difficult with aromatic ones, but now they are trying to reduce their use for a number of reasons. But mainly, of course, oil. In addition, it is worth mentioning phenol, chlorobenzene, nitrobenzene, aniline – they all rest on benzene.

Alcohols, acetone, acetic acid derivatives. We dealt with ethanol and ethylene glycol earlier; in short, it’s possible without oil and gas. Fatty alcohols, primarily butanol, are produced mainly from bio-based raw materials. We also talked about acetone in the previous section; isopropyl alcohol is made from it. A fairly large share in the production of solvents is occupied by esters of acetic acid – ethyl acetate, butyl acetate. They are made from vinegar and alcohols, see above.

Ether solvents. Diethyl ether from ethanol, dioxane, all sorts of dimethoxyethanes and cellosolves from ethylene glycol and corresponding alcohols – methanol, ethanol, butanol.

Organochlorine. Dichloroethane, a precursor to vinyl chloride, is made from ethylene or acetylene, we have already mentioned this. Chlorinated methane gases are produced from methane, which is natural gas.

In general, the situation here is somewhat easier than in polymers. Petrochemicals still take up the majority of production volumes, but there are more alternatives. Moreover, solvents, unlike monomers or base reagents, are not a dogma for industrial processes, and in many places they can be replaced by a wide range of analogues. In general, efforts are now being made to eliminate hydrocarbon and organochlorine solvents and to increase the efficiency of solvent recycling.

Then I will finish the conversation about industries that operate mostly with chemicals in the usual sense, and next time we will discuss fertilizers, metallurgy, building materials and other “chemical-related industries.”