What is the difference between alkylated products and aromatized products?

The difference between alkylated products and aromatized products is that one has a straight-chain structure while the other has a cyclic structure.

The alkylation process is also a type of advanced processing technique for liquefied gas. Similar to aromatization, it uses tetrahydroether (a by-product of MTBE production) as raw material to produce aromatic gasoline and household liquefied gas through specialized equipment. Alkylation is the main \"competitor\" of aromatization, outperforming the aromatization process in various aspects. Technically, the yield of aromatic gasoline produced by aromatization units is 30%-40%, which is much lower than the 70%-80% yield of alkylated gasoline produced by alkylation units. The high yield of alkylation units results in lower production costs, making their products more competitive in the market compared to those from aromatization units. Alkylation not only yields significantly higher product rates than aromatization, but the products resulting from alkylation – alkylated gasoline – also have a better market appeal than aromatized gasoline. On one hand, the quality parameters of alkylated gasoline are superior to those of aromatized gasoline; for example, its octane rating is generally between 95-96, while that of aromatic gasoline is usually between 90-93, which meets the requirements of gasoline formulators better ； On the other hand, regarding the gasoline standards that China aims to implement at present, there are stricter requirements regarding the octane rating and sulfur content of the raw materials used for gasoline production; as a result, gasoline producers are gradually shifting from purchasing aromatic gasoline to purchasing alkylated gasoline. The gradual increase in the price of C4 after etherification of feed gas has further exacerbated the difficulties faced by aromatization companies. Initially, post-ether carbon tetra was used merely as ordinary liquefied gas. Later, it was discovered that this feedstock could not only be used to produce household liquefied gas but also to generate aromatics for use in oil blending. As a result, post-ether carbon tetra gained new recognition in the market and its value began to rise steadily.

In these various processes, tetra-carbon compounds are used to lengthen hydrocarbon chains or increase molecular weight, thereby producing oil-based chemicals that are liquid under normal conditions (or as components for gasoline blending). While refining processes involve breaking down large crude oil molecules into smaller ones, the three processes mentioned above involve converting small C4 molecules back into larger oil molecules. 1. Aromatization: As the name suggests, C4 compounds are transformed into aromatic hydrocarbons such as benzene, toluene, and xylene under the action of catalysts and specific conditions; these can be used as additives in high-octane gasoline. The mainstream processes for aromatization in China are those developed by Dalian University of Technology and Shandong Qiwangda, as well as those designed by Luoyang Institute of Design. 2. Alkylation: Alkyl groups represent ideal hydrocarbon structures, being saturated hydrocarbons; C4 compounds are used to produce alkane oils with longer molecular chains, such as C6, C7, and C8 alkanes, which can be used directly in gasoline. The gasoline produced through alkylation is of high quality, but dealing with waste acids generated during the process requires careful handling. It is believed that this issue has now been resolved. 3. Isomerization: This process involves rearranging molecular structures. In the petroleum refining industry, isobutane obtained through the isomerization of n-butane can serve as a key raw material for producing octane, which is used as an additive in high-octane aviation gasoline. Therefore, n-butane isomerization units are often used in conjunction with isobutane alkylation units. Branched compounds resulting from the isomerization of C5 and C6 alkanes, such as isopentane and isohexane, can also be used as additives in high-octane gasoline. The isomerization process can also be utilized to increase the yield of desired products. For example, after separating p-xylene from an C8 aromatic mixture, isomerization reactions can be used to obtain an C8 aromatic mixture with a balanced composition, after which p-xylene can be separated again. This approach allows for the maximum recovery of the desired product, p-xylene.

One of them that is formed is an alkane, while the other is an aromatic compound