12 added 38 characters in body edited Jan 19 at 23:08 Karl 7,0521515 silver badges3636 bronze badges That's hard to tell, because already the next one after tetramethylbutane, tetra-tert-butylmethane (3,3-di-tert-butyl-2,2,4,4-tetramethylpentane) is so unstable it cannot exist. You want a parent chain that is even two atoms longer. Actually it seems also removing one methyl group from $$\ce{tBu_4}$$methane doesn't make it sufficiently stable, so one has to be a bit more generous in weeding out branches for larger hyperbranched alkanes. I believe that any permethylated (or per-n-alkylated) linear chain is principally possible, but adding more side-side chains to adjacent side chains will make the molecule snap in two. So the biggest possible sum formula would be something based on 3,5-di-tert-butyl-2,2,3,4,4,5,6,6-octaamethylheptane = $$\ce{C23H48}$$ . You can surely make the inner methyl substituents longer, 3,5-di-tert-butyl-3,5-diethyl-4,4-di-n-propyl-2,2,6,6-tetraamethylheptane = $$\ce{C29H60}$$ , and then you can probably add 4 methlymethyl to the nPr and Et to give iBu and i-Pr that's $$\ce{C33H68}$$. Any more and I'll bet it breaks, quite a way from the theoretical $$\ce{C53H108}$$. That's hard to tell, because already tetra-tert-butylmethane (3,3-di-tert-butyl-2,2,4,4-tetramethylpentane) is so unstable it cannot exist. You want a parent chain that is even two atoms longer. Actually it seems also removing one methyl group from $$\ce{tBu_4}$$methane doesn't make it sufficiently stable, so one has to be a bit more generous in weeding out branches for larger hyperbranched alkanes. I believe that any permethylated (or per-n-alkylated) linear chain is principally possible, but adding more side-side chains to adjacent side chains will make the molecule snap in two. So the biggest possible sum formula would be something based on 3,5-di-tert-butyl-2,2,3,4,4,5,6,6-octaamethylheptane = $$\ce{C23H48}$$ . You can surely make the inner methyl substituents longer, 3,5-di-tert-butyl-3,5-diethyl-4,4-di-n-propyl-2,2,6,6-tetraamethylheptane = $$\ce{C29H60}$$ , and then you can probably add 4 methly to the nPr and Et to give iBu and i-Pr that's $$\ce{C33H68}$$. Any more and I'll bet it breaks, quite a way from the theoretical $$\ce{C53H108}$$. That's hard to tell, because already the next one after tetramethylbutane, tetra-tert-butylmethane (3,3-di-tert-butyl-2,2,4,4-tetramethylpentane) is so unstable it cannot exist. You want a parent chain that is even two atoms longer. Actually it seems also removing one methyl group from $$\ce{tBu_4}$$methane doesn't make it sufficiently stable, so one has to be a bit more generous in weeding out branches for larger hyperbranched alkanes. I believe that any permethylated (or per-n-alkylated) linear chain is principally possible, but adding more side-side chains to adjacent side chains will make the molecule snap in two. So the biggest possible sum formula would be something based on 3,5-di-tert-butyl-2,2,3,4,4,5,6,6-octaamethylheptane = $$\ce{C23H48}$$ . You can surely make the inner methyl substituents longer, 3,5-di-tert-butyl-3,5-diethyl-4,4-di-n-propyl-2,2,6,6-tetraamethylheptane = $$\ce{C29H60}$$ , and then you can probably add 4 methyl to the nPr and Et to give iBu and i-Pr that's $$\ce{C33H68}$$. Any more and I'll bet it breaks, quite a way from the theoretical $$\ce{C53H108}$$. 11 edited body edited Jan 19 at 18:00 Karl 7,0521515 silver badges3636 bronze badges That's hard to tell, because already tetra-tert-butylmethane (3,3-di-tert-butyl-2,2,4,4-tetramethylpentane) is so unstable it cannot exist. You want a parent chain that is even two atoms longer. Actually it seems also removing one methyl group from $$\ce{tBu_4}$$methane doesn't make it sufficiently stable, so one has to be a bit more generous in weeding out branches for larger hyperbranched alkanes. I believe that any permethylated (or per-n-alkylated) linear chain is principally possible, but adding more side-side chains to adjacent side chains will make the molecule snap in two. So the biggest possible sum formula would be something based on 3,5-di-tert-butyl-2,2,3,4,4,5,6,6-octaamethylheptane = $$\ce{C21H44}$$$$\ce{C23H48}$$ . You can surely make the inner methyl substituents longer, 3,5-di-tert-butyl-3,5-diethyl-4,4-di-n-propyl-2,2,6,6-tetraamethylheptane = $$\ce{C25H52}$$$$\ce{C29H60}$$ , and then you can probably add 4 methly to the nPr and Et to give iBu and i-Pr that's $$\ce{C29H60}$$$$\ce{C33H68}$$. Any more and I'll bet it breaks, quite a way from the theoretical $$\ce{C53H108}$$. That's hard to tell, because already tetra-tert-butylmethane (3,3-di-tert-butyl-2,2,4,4-tetramethylpentane) is so unstable it cannot exist. You want a parent chain that is even two atoms longer. Actually it seems also removing one methyl group from $$\ce{tBu_4}$$methane doesn't make it sufficiently stable, so one has to be a bit more generous in weeding out branches for larger hyperbranched alkanes. I believe that any permethylated (or per-n-alkylated) linear chain is principally possible, but adding more side-side chains to adjacent side chains will make the molecule snap in two. So the biggest possible sum formula would be something based on 3,5-di-tert-butyl-2,2,3,4,4,5,6,6-octaamethylheptane = $$\ce{C21H44}$$ . You can surely make the inner methyl substituents longer, 3,5-di-tert-butyl-3,5-diethyl-4,4-di-n-propyl-2,2,6,6-tetraamethylheptane = $$\ce{C25H52}$$ , and then you can probably add 4 methly to the nPr and Et to give iBu and i-Pr that's $$\ce{C29H60}$$. Any more and I'll bet it breaks, quite a way from the theoretical $$\ce{C53H108}$$. That's hard to tell, because already tetra-tert-butylmethane (3,3-di-tert-butyl-2,2,4,4-tetramethylpentane) is so unstable it cannot exist. You want a parent chain that is even two atoms longer. Actually it seems also removing one methyl group from $$\ce{tBu_4}$$methane doesn't make it sufficiently stable, so one has to be a bit more generous in weeding out branches for larger hyperbranched alkanes. I believe that any permethylated (or per-n-alkylated) linear chain is principally possible, but adding more side-side chains to adjacent side chains will make the molecule snap in two. So the biggest possible sum formula would be something based on 3,5-di-tert-butyl-2,2,3,4,4,5,6,6-octaamethylheptane = $$\ce{C23H48}$$ . You can surely make the inner methyl substituents longer, 3,5-di-tert-butyl-3,5-diethyl-4,4-di-n-propyl-2,2,6,6-tetraamethylheptane = $$\ce{C29H60}$$ , and then you can probably add 4 methly to the nPr and Et to give iBu and i-Pr that's $$\ce{C33H68}$$. Any more and I'll bet it breaks, quite a way from the theoretical $$\ce{C53H108}$$. 10 added 262 characters in body edited Jan 19 at 17:29 Karl 7,0521515 silver badges3636 bronze badges That's hard to tell, because already tetra-tert-butylmethane (3,3-di-tert-butyl-2,2,4,4-tetramethylpentane) is so unstable it cannot exist. You want a parent chain that is even two atoms longer. Actually it seems also removing one methyl group from $$\ce{tBu_4}$$methane doesn't make it sufficiently stable, so one has to be a bit more generous in weeding out branches for larger hyperbranched alkanes. I believe that any permethylated (or per-n-alkylated) linear chain is principally possible, but adding more side-side chains to adjacent side chains will make the molecule snap in two. So the biggest possible sum formula would be somewhere in the range ofsomething based on 3,5-di-tert-butyl-2,2,3,4,4,5,6,6-octaamethylheptane = $$\ce{C21H44}$$ . A bit more, because youYou can likelysurely make the inner methyl substituents longer, 3,5-di-tert-butyl-3,5-diethyl-4,4-di-n-propyl-2,2,6,6-tetraamethylheptane = $$\ce{C25H52}$$ , and then you can enlarge probably add 4 methly to the nPr and Et to give iBu and si-BuPr that's $$\ce{C29H60}$$. Any more and I'll bet it breaks, quite a way from the theoretical $$\ce{C53H108}$$. That's hard to tell, because already tetra-tert-butylmethane (3,3-di-tert-butyl-2,2,4,4-tetramethylpentane) is so unstable it cannot exist. You want a parent chain that is even two atoms longer. Actually also removing one methyl group from $$\ce{tBu_4}$$methane doesn't make it sufficiently stable, so one has to be a bit more generous in weeding out branches for larger hyperbranched alkanes. I believe that any permethylated (or per-n-alkylated) linear chain is principally possible, but adding more side-side chains to adjacent side chains will make the molecule snap in two. So the biggest possible sum formula would be somewhere in the range of 3,5-di-tert-butyl-2,2,3,4,4,5,6,6-octaamethylheptane = $$\ce{C21H44}$$ . A bit more, because you can likely make the inner methyl substituents longer, 3,5-di-tert-butyl-3,5-diethyl-4,4-di-n-propyl-2,2,6,6-tetraamethylheptane = $$\ce{C25H52}$$ , and then you can enlarge probably the nPr and Et to iBu and s-Bu that's $$\ce{C29H60}$$. Any more and I'll bet it breaks, quite a way from the theoretical $$\ce{C53H108}$$. That's hard to tell, because already tetra-tert-butylmethane (3,3-di-tert-butyl-2,2,4,4-tetramethylpentane) is so unstable it cannot exist. You want a parent chain that is even two atoms longer. Actually it seems also removing one methyl group from $$\ce{tBu_4}$$methane doesn't make it sufficiently stable, so one has to be a bit more generous in weeding out branches for larger hyperbranched alkanes. I believe that any permethylated (or per-n-alkylated) linear chain is principally possible, but adding more side-side chains to adjacent side chains will make the molecule snap in two. So the biggest possible sum formula would be something based on 3,5-di-tert-butyl-2,2,3,4,4,5,6,6-octaamethylheptane = $$\ce{C21H44}$$ . You can surely make the inner methyl substituents longer, 3,5-di-tert-butyl-3,5-diethyl-4,4-di-n-propyl-2,2,6,6-tetraamethylheptane = $$\ce{C25H52}$$ , and then you can probably add 4 methly to the nPr and Et to give iBu and i-Pr that's $$\ce{C29H60}$$. Any more and I'll bet it breaks, quite a way from the theoretical $$\ce{C53H108}$$. 9 added 262 characters in body edited Jan 19 at 17:17 Karl 7,0521515 silver badges3636 bronze badges 8 added 51 characters in body edited Jan 19 at 16:34 Karl 7,0521515 silver badges3636 bronze badges 7 added 17 characters in body edited Jan 19 at 15:10 Karl 7,0521515 silver badges3636 bronze badges 6 deleted 57 characters in body edited Jan 19 at 14:46 Karl 7,0521515 silver badges3636 bronze badges 5 added 180 characters in body edited Jan 19 at 14:35 Karl 7,0521515 silver badges3636 bronze badges 4 added 180 characters in body edited Jan 19 at 14:28 Karl 7,0521515 silver badges3636 bronze badges 3 added 144 characters in body edited Jan 19 at 14:19 Karl 7,0521515 silver badges3636 bronze badges 2 added 90 characters in body edited Jan 19 at 14:07 Karl 7,0521515 silver badges3636 bronze badges 1 answered Jan 19 at 14:01 Karl 7,0521515 silver badges3636 bronze badges