SCIENCEscience.org 4 MARCH 2022¥VOL 375 ISSUE 6584 1023
Fig. 2. Catalytic reaction ofa-olefins and ethylene.(A) Temperature
dependence of the selectivity of liquid co-oligomerization products of 1-hexene
with ethylene. The 1-butene co-product can be boiled off easily at the end of the
reaction. All runs were carried out three times to confirm reproducibility and
determine a standard deviation (SD), which is given in parentheses. The TOFs
were calculated based on the formation of liquid products only. Conditions are as
follows:Peth= 1.0 bar;t= 15 min; precatalyst isn 3 = 0.05mmol; ammonium
borate activator is [R 2 N(CH 3 )H]+[B(C 6 F 5 ) 4 ]−(R = C 16 H 33 to C 18 H 37 ); Ti/B = 1/1.1;
VC6= 30 ml; and scavenger is 300mmol TIBA. (B) Proposed mechanism of
the reaction ofa-olefins with two ethylene molecules.à, transition state. (C) The
1-GHz^1 H NMR spectrum of 4-ethyloct-1-ene, the elongation and branching
product of 1-hexene. Insets show multiplets of key signals.Fig. 3. Elongation and branching ofa-olefins.(A) A run for the multigram
synthesis of 4-ethyldec-1-ene of 1 hour (300-ml reactor). A combination of two
runs and a single simple distillation gave rise to 18 g of product with a purity
96%. The constant ethylene flow (black) for more than 30 min was confirmed by
a linear fit (blue). (B) Elongation and branching of an already elongated product.
4-Ethyldec-1-ene, the elongation and branching product of 1-octene, has been
further elongated to form 4,6-diethyldodec-1-ene with a selectivity of 65 mol %
for the liquid products (Volefin= 1.2 ml;Vtoluene= 2 ml). (C) Elongation and
branching of styrene (Vstyrene= 15 ml). (D) Elongation and branching of bicyclo
[2.2.1]hept-2-ene (Peth= 4.0 bar; 100 mg olefin;Vtoluene= 6.5 ml). Selectivity
(co-oligomerization products) and TOF (product only) were calculated by
averaging three experiments for (A), (C), and (D) and two experiments for (B).
SDs are given in parentheses. Standard conditions (see Table 1) and
modifications listed above were applied.RESEARCH | REPORTS