The Application Of High Resolution Mass Spectrometry Collision Induced Dissociation In The Study Of Heavy Oil Polar Compounds

The emergence of ultra-high resolution mass spectrometry has made the study of heavy oil molecular composition a reality and researchers have done lots of works in this field.However,conventional ultrahigh resolution mass spectrometry can only provide molecular formula information but not molecular structure information.Collision induced dissociation(CID)process can be used to fragment ions,and structural information can be obtained by analyzing fragment ions.This thesis adopted tamdem mass spectrometry technology,which combine collision induced dissociation(CID)process with conventional high-resolution mass spectrometry.By analysis the mass spectrometry of heavy oil in CID process,its structural characteristics were inferred.Firstly,this thesis examing the cracking reactions characteristics of Venezuela vacuum residue in CID process.Different reaction depths were achieved by changing the collison voltages.At the same time,the cracking reaction in thermal reaction of Venezuela VR was used as a reference to help understand the characteristics of the CID cracking behavior,By changing the pyrolysis temperature,products of different reaction depths were obtained,then analyzed by FT-ICR MS in detail.The results show that there is certain similarity of reaction characteristics between the two processes,both existing obvious molecular weight reduction caused by the side chain breakage.And there is a certain correspondence between the reaction temperature and the collision energy in terms of average carbon number change.Both desulfurization and decarboxylation were observed in two processes due to the low C-S bond energy and poor stability of carboxylic acid groups.Nevertheless,the two processes still have some differences in reaction selectivity.Part of substituted aromatic tends to directly dealkylated down to C1 substituted structure in the CID process,and exhibiting a jump discontinuity reduction in carbon number,while thermal reaction decreases more moderately and continuously.In order to study the structure of heavy oil polar compounds,and considering the difficulty of studying the molecular structure of monomers in heavy oil,first select four type nitrogen-containing model compounds to help understand the structural information of heavy oil.We obeseved two archipelago-structure compounds(3-benzylpyridine,4-(2-(naphthalen-1-yl)ethyl)pyridine)and three aromatic amines(naphthalen-1-ylmethanamine,(R)-1-(naphthalen-2-yl)ethanamine,N-methyl-1-(naphthalen-2-yl)ethanamine)can generate HC fragments,but aromatic amines are extremely unstable,thus impossible to stabilize in oil.On the basis of the above work,this paper studied the molecular composition distribution of polar compounds before and after the CID of four heavy petroleum(Venezuela vacuum residuum,Sudan's vacuum residue,Canada oil sand and Liaohe ultra heavy oil).It was found that all the four heavy oil CID processes generate high aromatic and short-chain hydrocarbon fragments,and S1 fragments.According to the discussion of the model compounds in the previous article,the existence of archipelagic compounds in heavy oils were confirmed,the proportion of the archipelago structure of the four heavy oils is obtained by the relative content of HC and S1 fragments...