Replacement of Hazardous Chemicals Used in Engineering Plastics with Safe and Renewable Hydrogen-Bond Donor and Acceptor Solvent-Pair Mixtures

Abstract

Mixtures of safe and renewable solvents can replace hazardous solvents presently being used in the manufacture of engineering plastics. In this work, a methodology is proposed for identifying solvent-pair mixtures for preparing polymer precursors, with poly(amic acid) (PAA) being studied as an example. The methodology uses a chemical safety index, Hansen solubility parameters and Kamlet−Taft solvatochromic parameters of the pure and solvent-pair mixtures to identify hydrogen bond acceptor (HBA)−hydrogen bond donor (HBD) solvent-pair combinations. Ten replacement solvent-pairs for PAA syntheses identified were cyclohexanone−methanol, cyclohexanone−ethanol, cyclopentanone−methanol, cyclopentanone−ethanol, γ-butyrolactone−methanol, γ-butyrolactone− ethanol, γ-butyrolactone−water, γ-valerolactone−methanol, γ-valerolactone−ethanol, and γ-valerolactone−water. Homogeneous PAA solutions could be obtained from HBA−HBD solvent-pair mixtures when their solubility parameters were within 21−29 MPa 0.5 and their Kamlet−Taft solvatochromic parameters were π* (>0.67) and β (>0.67) for nonaqueous solutions and π* (>0.68) and β (>0.59) for aqueous solutions. Replacement solvent-pairs, γ-valerolactone−ethanol, γ-valerolactone−water, and γ-butyrolactone−water gave homogeneous precursor solutions that were comparable with commercial solutions prepared with Nmethyl-2-pyrrolidone. The proposed methodology and reported solvatochromic parameters make it is possible to identify other solvent-pair mixtures and new solvent-pairs for preparing polymer precursor solutions used in engineering plastics.

Momilactones A and B: Optimization of Yields from Isolation and Purification

“…Temperature and pressure have been effective in optimizing yields of natural products, especially in industrial scale [33]. The replacement of MeOH by EtOH to reduce the hazardous possibility [34] during extraction of MA and MB should be also considered. In general, MA was found to be greater in quantity than MB in both rice and H. plumaeforme (Table 2).…”

Identification of high performance solvents for the sustainable processing of graphene

“…To assess the role of surface tension, polarity, and viscosity in detail, a database of more than 10,000 solvents (containing 51 bio based solvents) was screened against the extended physical property criteria (phase 1), followed by toxicity, then environmental persistency, bioaccumulation, and aquatic toxicity (phase 2) through a series of stage gates (see Figure 2a for a summary of the screening procedure), as fully explained in the Supporting Information. Algorithms for solvent selection have been used previously to optimize extractions, reaction chemistry, 51 and for the selection of green alternative solvent pairs for polymer synthesis, 52 but to date this approach has not been extended to the more complex problem of graphite exfoliation and dispersion. By applying our algorithm the large dataset was refined to just 8 solvents that both satisfied all of the physical property requirements and were compliant with REACH.…”

Crystallinity of regenerated cellulose from [Bmim]Cl dependent on the hydrogen bond acidity/basicity of anti-solvents

“…20,[33][34][35] Here, the sum of a + b + p* was introduced to evaluate the interaction between the ILs and anti-solvents (Fig. 6c).…”