Process NMR

Table 4 13C NMR derived Average Molecule Parameters

General Carbon Types:
Aromatic CarbonAtomic percent of carbons in aromatic groups.
Aliphatic CarbonAtomic percent of carbons in naphthenic or paraffinic components.
Carboxylic/Carbonyl CarbonAtomic percent of carbons in carboxylic acids, esters, amides, ketones or aldehyde groups.
Protonated Aromatic CarbonAtomic percent of aromatic carbons with hydrogen attached.
Alkyl-Substituted Aromatic CarbonAtomic percent of aromatic carbons with alkyl groups attached.
Methine CarbonAtomic percent of aliphatic (naphthenic or paraffinic) methine carbons.
Methylene CarbonAtomic percent of aliphatic (naphthenic or paraffinic) methylene carbons.
Methyl CarbonAtomic percent of aliphatic (naphthenic or paraffinic) methyl carbons.

Aromatic Carbon Breakdown:
Carbonyl CarbonAtomic percent carbon present as aldehydes and ketones.
Carboxyl CarbonAtomic percent carbon present as esters, amides, acids and anhydrides.
Heteroaromatic CarbonAtomic percent carbon present as aromatic carbon adjacent to nitrogen, sulfur, or oxygen.
Methylene/Methine-Substituted Aromatic CarbonAtomic percent carbon present as aromatic carbon substituted by an alkyl group through a methine or methylene carbon.
Naphthene-Substituted Aromatic CarbonAtomic percent carbon present as aromatic carbon substituted by naphthenic carbon groups.
Methyl-Substituted Aromatic CarbonAtomic percent carbon present as aromatic carbon substituted by a methyl group.
Internal Aromatic CarbonAtomic percent carbon present as bridgehead aromatic carbons in polynuclear aromatics.
Methyl CarbonAtomic percent of aliphatic (naphthenic or paraffinic) methyl carbons.

Naphthenic Carbon Breakdown:
Total Naphthenic CarbonAtomic percent carbon present as naphthenic (cyclic aliphatic) carbon.
Naphthenic Methine CarbonAtomic percent carbon present as methines in naphthenic ring systems.
Naphthenic Methylene CarbonAtomic percent carbon present as methylene in naphthenic ring systems.
Naphthenic Methyl CarbonAtomic percent carbon present as methyls attached to naphthenic ring systems.

Paraffinic Carbon Breakdown:
Paraffinic CarbonAtomic percent carbon present as paraffinic carbon.
N-Paraffin Character of SampleAtomic percent carbon present as paraffinic methyls and methylenes in uninterrupted straight paraffin chain sequences.
N-Paraffin Character of ParaffinsPercent of the paraffinic carbons themselves that are present in uninterrupted straight paraffin chain sequences.
Degree of Branching in ParaffinsThis is a ratio comparison of branching paraffinic carbons against straight chain paraffins. The higher the ratio the more branched the paraffinic carbon component of the sample.
Average Paraffin Straight Chain LengthAverage length of uninterrupted methylene sequences in paraffinic chains, i.e. takes into account length of methylene sequences in all N-paraffins, isoparaffins and branched paraffins. This should not be confused with wax content which cannot be determined by NMR of a bulk sample.

Average Molecule Description:
Mole Fraction of Bridgehead AromaticsRatio of bridgehead aromatic carbon content with total aromatic carbon content.
Average Number of Aromatic Carbons per ClusterNumber of carbon atoms in the average aromatic cluster, i.e. 6 = single ring, 10 = naphthalene, 14 = anthracene, 18 = pyrene, etc. This is calculated from the Mole Fraction of Bridgehead Aromatics assuming linear concatenation of the aromatics.
Average Number of Aromatic Clusters per 100 CarbonsSimply the total aromatic carbon percentage divided by the average number of aromatic carbons per cluster. This number is needed to obtain the average functional group makeup of the "average" molecule in the sample.
Average Number of Alkyl Substitutions per Aromatic ClusterAverage number of alkyl (naphthenic or paraffinic) substitutions on the average aromatic cluster.
Average Number of Methyl Substitutions Per aromatic ClusterAverage number of methyl groups attached directly to the aromatic cluster.
Average Number of Napthenic Substitutions per ClusterAverage number of aromatic carbons substituted by a naphthenic carbon (methine or methylene).
Average CH2/CH Substitutions per ClusterAverage number of aromatic carbons substituted by a paraffinic carbon (methine or methylene).
Average Number of Heteroatoms per ClusterAverage number of N, S, or O atoms per aromatic cluster.
Average Number of Naphthenic CH3 per ClusterAverage number of methyl carbons attached to naphthenic ring systems.
Average Number of Naphthenic Rings per ClusterAverage number of naphthenic rings attached to the average aromatic cluster. This is based on the total napthenic carbon content and assuming all the rings are 6-membered.
Average Number of Paraffinic Carbons per Cluster Average number of paraffinic carbons substituted onto the average aromatic cluster. This is simply the total paraffin content divided by the number of aromatic clusters per 100 carbons. NMR cannot distinguish between alkyl-aromatics with long paraffinic groups and totally paraffinic molecules. This number should be contrasted with the Average Paraffin Straight Chain Length parameter.
Average Chain Length of Paraffinic SubstitutionsThis number is obtained by dividing the Average number of paraffins per aromatic cluster by the number of CH/CH2 substitutions per cluster. Obviously this number is not realistic and should also be contrasted with the Average Paraffin Straight Chain Length parameter.
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