Why are olefins important? You may not have heard of this term, but it fills your life

Produced by: Science Popularization China

Author: Denovo

Producer: China Science Expo

When you mention chemical products, do you think of "technology and hard work"? In fact, chemical products play a vital role in people's daily lives.

From advanced food packaging to a series of toiletries such as hand sanitizers, as well as disinfectants used for cleaning, people's lives are inseparable from chemical products. As the "cornerstone of national life", every advancement in chemical technology is invisibly driving social development forward.

When we talk about the traditional chemical industry, the first thing that comes to our mind is petrochemicals. But what is indispensable in petrochemicals?

The answer is olefins.

Petrochemical Plant

(Image source: Wikipedia)

Concept Sorting - Petroleum, Ethylene and Olefins

When it comes to olefins, many people may be confused, but most people are much more familiar with ethylene. As we all know, petrochemicals are closely related to energy, textiles, printing and dyeing, rubber, plastics, drug production, etc. Ethylene, as a by-product of the petroleum industry, its output reflects whether the petrochemical industry is prosperous. Therefore, ethylene is also considered an important indicator of a country's chemical level.

What is the relationship between ethylene and today's protagonist - olefins?

In organic chemistry, "hydrocarbon" refers to an organic compound composed of only two elements, carbon and hydrogen. Olefins are hydrocarbons containing C=C double bonds (carbon-carbon double bonds), and are unsaturated hydrocarbons. At the same time, the simplest olefin has only one C=C double bond and no other functional groups, so it was named ethylene by the International Union of Pure and Applied Chemistry (IUPAC). Therefore, olefins are also called vinyl compounds.

Model diagram of ethylene

Image source: Wikipedia

Understand the characteristics——Special properties given by the unique double bond

The unique double bond of olefins (i.e., C=C double bond, also known as carbon-carbon double bond) gives them many special properties. Although olefins are relatively stable compounds, they are more reactive than alkanes (single-bond hydrocarbons) due to the presence of C=C double bonds.

Most reactions of olefins are related to the C=C double bond. The double bond consists of a δ bond and a π bond. The π bond is unstable due to its high energy. When the double bond is attacked by other reagents, the π bond will break, thus forming a new chemical structure.

Schematic diagram of the nucleophilic addition reaction of alkenes

Image source: Wikipedia

Exploring the “predecessors” – where do olefins come from?

Most olefins are derived from crude oil, not because they exist in large quantities in crude oil, but because they are produced by cracking the alkanes in crude oil.

Cracking is the process of breaking down alkanes using heat and catalysts. The cracking process is important because it converts less useful long-chain alkanes into smaller, more useful alkanes, which in turn produce more valuable olefins such as ethylene and propylene. Currently, the main production processes in the global ethylene industry are steam cracking and methanol to olefins (MTO).

Schematic diagram of cracking into olefins and alkanes

(Image source: drawn by the author)

From toys to cosmetics - a diverse range of uses comparable to an encyclopedia

Ethylene is one of the most important petrochemical derived monomers and has the largest olefin market. Studies have shown that among the most important and abundant organic chemicals produced worldwide, two simple alkenes, ethylene and propylene, are among them, and they are used as starting materials to synthesize many valuable compounds.

Table 1 Chemical products produced from ethylene as raw material

Table 2 Chemical products prepared from propylene as raw material

According to the Global Ethylene Market Research Report, the global ethylene production capacity is estimated at 216.35 million tons/year in 2021. The market is expected to grow at an average annual rate of more than 7% from 2021 to 2026. The United States, China, Saudi Arabia, South Korea, and Iran are the key countries in the world that account for more than 50% of the total ethylene production.

From the regional perspective of the global ethylene industry, the key regions of the global ethylene industry are Asia, North America, the Middle East, Europe, the former Soviet Union, South America and Africa, and Asia is the region that contributes the most to global ethylene production capacity.

A hypothesis - what would the world be like without olefins?

As one of the important raw materials for the economy and production society, olefins span polymer materials and fine chemicals. The upstream production capacity of ethylene, propylene and other products directly determines the downstream chemical product production capacity, affecting our lives in all aspects.

The main commodities in the global petrochemical market are ammonia, urea, ethylene, methanol, propylene, polyethylene, purified terephthalic acid (PTA), polypropylene and xylene. Among them, ammonia has the highest capacity, followed by propylene, polyethylene, PTA, followed by polypropylene, and finally xylene.

It is not difficult to see that olefins play a pivotal role in the global petrochemical market, and ethylene also plays an irreplaceable role. The reduction in olefin production capacity may lead to a shortage of many living resources. To put it more concretely, without olefins, we may have to live in rough houses and take a shower with clean water.

References:

【1】Masih M, Algahtani I, De Mello L. Price dynamics of crude oil and the regional ethylene markets[J]. Energy Economics, 2010, 32(6): 1435-1444.

【2】Alshammari A, Kalevaru VN, Bagabas A, et al. Production of ethylene and its commercial importance in the global market[M]//Petrochemical catalyst materials, processes, and emerging technologies. IGI Global, 2016: 82-115.

【3】Eramo M. Shale energy resources driving resurgence for ethylene industry[J]. Hydrocarbon Processing, 2013.