2 research outputs found
Millisecond Pulsed Films Unify the Mechanisms of Cellulose Fragmentation
The mechanism of crystalline cellulose
fragmentation has been debated
between classical models proposing end-chain or intrachain scission
to form short-chain (molten) anhydro-oligomer mixtures and volatile
organic compounds. Models developed over the last few decades suggest
global kinetics consistent with either mechanism, but validation of
the chain-scission mechanism via measured reaction rates of cellulose
has remained elusive. To resolve these differences, we introduce a
new thermal-pulsing reactor four orders of magnitude faster than conventional
thermogravimetic analysis (10<sup>6</sup> vs 10<sup>2</sup> °C/min)
to measure the millisecond-resolved evolution of cellulose and its
volatile products at 400–550 °C. By comparison of cellulose
conversion and furan product formation kinetics, both mechanisms are
shown to occur with the transition from chain-end scission to intrachain
scission above 467 °C concurrent with liquid formation comprised
of short-chain cellulose fragments
Tunable Oleo-Furan Surfactants by Acylation of Renewable Furans
An
important advance in fluid surface control was the amphiphilic
surfactant composed of coupled molecular structures (i.e., hydrophilic
and hydrophobic) to reduce surface tension between two distinct fluid
phases. However, implementation of simple surfactants has been hindered
by the broad range of applications in water containing alkaline earth
metals (i.e., hard water), which disrupt surfactant function and require
extensive use of undesirable and expensive chelating additives. Here
we show that sugar-derived furans can be linked with triglyceride-derived
fatty acid chains via Friedel–Crafts acylation within single
layer (SPP) zeolite catalysts. These alkylfuran surfactants independently
suppress the effects of hard water while simultaneously permitting
broad tunability of size, structure, and function, which can be optimized
for superior capability for forming micelles and solubilizing in water