Application of NMR Spectroscopy in the Analysis of Petroleum Derivatives and Products

Složen kemijski sastav i fizikalna svojstva nafte i naftnih goriva čine njihovu karakterizaciju vrlo zahtjevnom. Pojedinačni spojevi, sastojci nafte i proizvoda razlikuju se po molekulskoj strukturi, veličini, polarnosti i funkcionalnosti. Sastav i prisutnost određenih specifičnih ugljikovodičnih skupina u određenom proizvodu ovisi o vrsti goriva i postupku procesa obrade. Kako bi se predvidjeli potencijali goriva ili odredili zahtjevi za poboljšanjem, potrebno je dobro poznavanje sastava goriva. U tu svrhu stalno se razvijaju nove i sve sofisticiranije analitičke tehnike i metode. Spektroskopija NMR ima široku primjenu u istraživanju sastava složenih ugljikovodičnih smjesa nafte i naftnih proizvoda. Pregledom je obuhvaćena njezina primjena u analizi benzinskih i dizelskih goriva. Opisana je važnost razvoja tehnika CP/MAS NMR za snimanje čvrstih uzoraka u analizi naftno-geokemijskih supstrata. Prikazane su mogućnosti spektroskopije NMR u karakterizaciji polimernih aditiva koji se upotrebljavaju u naftnoj industriji.Complex chemical composition and physical properties of oil and fuel make their complete characterization very difficult. Components present in oil and oil products differ in structure, size, polarity and functionality. The presence and structure of specific hydrocarbons in final products depend on the processing procedure and type of the fuel. In order to predict or improve fuel properties it is necessary to determine its composition. Thus, new and more sophisticated analytical methods and procedures are constantly being developed. NMR spectroscopy plays a significant role in analysis and identification of complex hydrocarbon mixtures of petroleum and petroleum products. In this review, we describe the application of NMR spectroscopy for analyzing gasoline and diesel fuels. Hence, by using NMR spectroscopy it is possible to determine gasoline composition and presence of benzene and oxygenates, as well as some important physical characteristics of gasoline such as the research octane number. An application of different NMR techniques made it possible to characterize diesel fuels and middle oil distillates from various refineries. Data so obtained can be used in combination with statistical methods to predict fuel properties and to monitor production processes in the petroleum industry. NMR spectroscopy has proven useful in analysis of FAME which has recently been used as an ecologically acceptable alternative fuel. Furthermore, techniques such as CP/MAS for characterization of solid state oil-geochemical samples are included. Also, possibilities of using NMR spectroscopy in the analysis of polymeric additives are discussed