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What would be the name of a linear alkane containing 10000 carbon atoms, i.e. $\ce{C10000H20002}$?

I have searched for it, but the longest alkane I could find had 9000 carbon atoms (and was apparently called nonaliane).

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    $\begingroup$ Chemistry.se has a dedicated resource page for study here, including a section about nomenclature. If IUPAC did not convene about systematic names with more 9000 carbon atoms in a straight chain, either a) because nobody needs this (at present) to describe his/her synthesis, or b) there are descriptors already in use (e.g., FASTA format in biochemistry) which are more efficient than using a nomenclature designed with smaller molecules in mind. $\endgroup$
    – Buttonwood
    Jan 26 at 17:32
  • $\begingroup$ Previously disussed: chemistry.stackexchange.com/questions/152181/…. Btw, where did you find 9000 carbon atoms? The longest I could find is 6000 atoms: cen.acs.org/articles/94/i15/…. "Nonaliane" also is not giving me sufficient results except: zuzentzailea.livejournal.com/4349.html $\endgroup$ Jan 27 at 5:46

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I suppose one can treat $\ce{C10000H20002}$ as polyethylene $\require{enclose}\ce{\enclose{horizontalstrike}{\;(}CH2\enclose{horizontalstrike}{)_n}}$ with the defined degree of polymerization, resulting in source-based IUPAC name polyethene (10000 DP) or polyethene (140000 $M_\mathrm{r}$) [1, pp. 315–317]:

11.2 Structure- and source-based names for common polymers

$$ \begin{array}{lll} \hline \text{Structure} & \text{Source-based name} & \text{Structure-based name }\\ & \text{(preferred given first)} & \\ \hline \require{enclose}\ce{\enclose{horizontalstrike}{\;(}CH2\enclose{horizontalstrike}{)_n}}^\textit{a} & \text{polyethene} & \text{poly(methylene)} \\ & \text{polyethylene}^\textit{b} & \\ \vdots & & \\ \hline \end{array} $$

$^\textit{a}$ The formulae $\require{enclose}\ce{\enclose{horizontalstrike}{\;(}CH2CH2\enclose{horizontalstrike}{)_n}}$ and $\require{enclose}\ce{\enclose{horizontalstrike}{\;(}CF2CF2\enclose{horizontalstrike}{)_n}}$ are more often used; they are acceptable due to past usage and an attempt to retain some similarity to the CRU formulae of homopolymers derived from other ethene derivatives.
$^\textit{b}$ Traditional names.

Further from [1, p. 351]:

Rule 1.8: Specifications about mass fractions $(w),$ mole fractions $(x),$ molar masses $(M),$ relative molecular masses $(M_\mathrm{r}),$ degrees of polymerization (DP) or the average values of the latter three quantities, may be expressed by placing the corresponding values in parentheses after the formula of the macromolecule in a manner analogous to that recommended for the naming of copolymers [6].

From subsection 8 Specification with regard to mass fractions, mole fractions, molar masses and degrees of polymerization [1, p. 381]:

Rule 8.3
The molar mass, relative molecular mass or degree of polymerization may be included in the scheme of Rules 8.1 and 8.2 by adding the corresponding figures, followed by the symbol $M,$ $M_\mathrm{r}$ or DP, respectively.

Examples:

  1. polybutadiene-graft-polystyrene (75:25 mass %; 90 000:30 000 $M_\mathrm{r}$) (a graft copolymer consisting of 75 mass % of butadiene units with a relative molecular mass of 90 000 as the backbone, and 25 mass % of styrene units in grafted chains with a relative molecular mass of 30 000)

  2. polybutadiene-graft-polystyrene (1700:290 DP) (a graft copolymer consisting of a polybutadiene backbone with a degree of polymerization of 1700 to which polystyrene with a degree of polymerization of 290 is grafted)

Reference

  1. IUPAC. Compendium of Polymer Terminology and Nomenclature: Recommendations 2008 (the “Purple Book”); Richard G. Jones, Jaroslav Kahovec, Robert Stepto, Edward S. Wilks, Michael Hess, Tatsuki Kitayama, W. Val Metanomski, Eds.; RSC Publishing: Cambridge, 2009. ISBN 978-0-85404-491-7.
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    $\begingroup$ Ah well, I guess it took me six minutes to write up my answer... I was thinking about mentioning the term degree of polymerization, but decided against it because I realized that I am unsure how to use it together with structure-based naming. Source-based naming feels not entirely spot-on here to me. $\endgroup$ Jan 26 at 18:48
  • $\begingroup$ @Snijderfrey It is not surprising that polythene can contain more than 10000 carbon atoms. LDPE contains 4000-40000 carbon atoms (often branched), UHMWP can have 500000 carbon atoms, so we are not bothered to name individual alkane. Even though they can be named according to IUPAC rules, they can be quite a mouthful to say. So, we can safely classify them as "polymer" or "polythene with X degree of polymerization" $\endgroup$ Jan 27 at 6:01
  • $\begingroup$ @NilayGhosh, yes, I am aware of the size of macromolecules. The answer here is good, I am just not sure about the DP given in "polyethene (10000 DP)". To my understanding, the DP should be 5000, but with the structure-based name poly(methylene) this seems strange. I asked a separate question to get some insight on how to use DP with structure-based nomenclature: chemistry.stackexchange.com/questions/162542/… $\endgroup$ Jan 27 at 8:26
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As far as I can tell, the answer is actually undefined, as the 2013 Blue Book only gives a formula for constructing so-called "numerical terms" or "multiplicative prefixes" up to the number 9999.

P-14.2 of the Blue Book gives multiplicative prefixes for all values of $n$, $10n$, $100n$, and $1000n$ (where $n$ is an integer between 1 and 9), so all numbers up to 9999 can be constructed by stringing these together. However, it stops abruptly at 9000, so we can't access anything beyond 9999.

For 9999 atoms, the corresponding prefix would be 'nonanonacontanonactanonalia' (nona = 9, nonaconta = 90, nonacta = 900, nonalia = 9000); so the linear alkane $\ce{C9999H20000}$ would be named nonanonacontanonactanonaliane, as specified by P-21.2.1 of the Blue Book:

Systematic names for the higher members of this series consist of a numerical term followed by the ending 'ane' with elision of the terminal letter 'a' from the numerical term.

The choice to stop at 9999 seems to have been conscious, although perhaps arbitrary: see e.g. https://iupac.qmul.ac.uk/misc/numb.html for more discussion. This was published in 1986:

Recently a desire has been expressed for numerical terms higher than 199. This document provides the necessary guidance, based on principles already established, for generating numerical terms up to 9999 by using the infixes "cta" (for the hundreds digits) and "lia" (for the thousands digits) in a way quite analogous to the use of "conta" for the tens digits beyond twenty.

I'm aware that this is old, but the 2013 Blue Book doesn't contain any more info beyond this.

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  • $\begingroup$ It could be argued that 9999-ane is simply the largest parent hydride in the compound; by that logic, 10000-ane would be called 1-methylnonanonacontanonactanonaliane. I think I once wrote a script to generate general linear alkane names based on that principle. It's actually pretty tricky, since it depends on the alphanumerical order of the substituents. $\endgroup$ Jan 27 at 4:36
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I suggest to think of $\ce{C10000H20002}$ as a uniform polymer (deprecated: monodisperse polymer). The correct name according to the IUPAC Recommendations on Polymer Terminology and Nomenclature (see the Purple Book) would then be poly(methylene) in the structure-based nomenclature or polyethene (preferred over polyethylene) in the source-based nomenclature.

If you want to distinguish between poly(methylene) with different chain lengths, you would usually use the molar mass.

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