Bases molecular formulas

Molecular formula Name Parent peak Base peak Three next most intense peaks ... 

Chlorinated paraffins with the general molecular formula x 2x-y+2) have been manufactured on a commercial basis for over 50 years. The early products were based on paraffin wax feedstocks and were used as fine retardants and plasticizers in surface coatings and textile treatments and as extreme pressure—antiwear additives in lubricants. The development of chlorinated paraffins into new and emerging technologies was constrained principally because of the limitations of grades based on paraffin wax and the lack of suitable alternative feedstocks to meet the demands of the new potential markets. 

Benzoyl chloride reacts with 2-mercaptoethanol in base to give an ester. When the reaction is monitored carefully, the rapid buildup of an intermediate, X , of molecular formula C9H10O2S, is observed. This is slowly transformed into the ester of the same molecular formula. Although ester formation is known to be a multi-step process, X does not correspond to any of the usual intermediates in ester formation. What is going on here ... 

Compilations of Reference Spectra There are several compilations of reference mass spectra available of which the oldest is the American Petroleum Institute (Ref 82) collection of spectra obtained mostiy on the older type instruments. Recent collections index spectra variously, eg, under reference number (Ref 19). molecular weight (Refs 12 19), molecular formula (Ref 19), fragment ion values (Ref 19), and base peak (Refs 12 19). A quarterly journal, Archives of Mass Spectral Data ... 

The following is a procedure recommended for elucidating the structure of complex organic molecules. It uses a combination of different NMR and other spectroscopic techniques. It assumes that the molecular formula has been deduced from elemental analysis or high-resolution mass spectrometry. Computer-based automated or interactive versions of similar approaches have also been devised for structural elucidation of complex natural products, such as SESAMI (systematic elucidation of structures by using artificial machine intelligence), but there is no substitute for the hard work, experience, and intuition of the chemist. 

ChemIDplus. Published by the U.S. National Library of Medicine, ChemIDplus [62] is a web-based search system, http //chem.sis.nlm.nih.gov/ chemidplus/, that provides free access to structure and nomenclature authority files used for the identification of chemical substances cited in National Library of Medicine (NLM) databases. ChemIDplus also provides structure searching and direct links to biomedical resources at NLM and on the Internet. The database contains over 349,000 chemical records, over 56,000 of which include chemical structures, and is searchable by name, synonym, CAS registry number, molecular formula, classification code, locator code, and structure. 

Pharmacological studies and clinical applications of individual Gelsemium alkaloids or of the total alkaloids have never been reviewed before, so a preliminary treatment is presented in this chapter based on the limited data collected so far. For the convenience of identification, the names, molecular formulas, sources, as well as main references of all the Gelsemium alkaloids reported in the literature to date are listed in Table I. 

The molecular peak of the spiro[adamantine-2,2 -(l,3,4)-thiadiazolidine]-3, 4 -dicarboxylate 29 appears with 99% intensity and shows four distinct fragmentations <1999T12783>. The molecular formulas of the fragments were confirmed by the intensities of 13C and (34S+13C2) isotope peaks. The two major fragmentations involve cleavage of the weak C-S bonds and afford the base peak at mjz 208 (100%) corresponding to and a peak at m/z 239... 

Acetylacetone, 7 148-149, 164 74 596-598 molecular formula, 5 712t TV-Acetylacrylamide, 7 293 Acetyl anchoring groups, 5 683t Acetylated cyclodextrin-based chiral stationary phase, 6 87 Acetylated lanolin, cosmetically useful lipid, 7 833t... 

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