Complete Green Metrics Evaluation of Various Routes to Methyl Methacrylate According to Material and Energy Consumptions and Environmental and Safety Impacts: Test Case from the Chemical Industry

In this paper we present a standardized
protocol for the complete
evaluation of greenness of 18 industrial routes to methyl methacrylate
(MMA) covering material and energy consumptions and environmental
and safety impacts. A methodology for estimating energy consumption
for chemical reactions and synthesis plans from published journal
and patent literature procedures is fully described. A new energy
metric pertaining to enthalpic changes from standard state conditions
(298 K, 1 atm) to reaction conditions (Trxn, prxn) for all input materials used
in a synthesis plan for the production of 1 mol of product is defined
with respect to the heating and evaporation of 1 mol of water from
298 K and 1 atm. Limitations and best practices of running the protocol
are discussed. The present study serves as a template for implementing
the protocol to the green metrics analysis of high volume industrial
chemicals. Results of plan rankings are compared with previous work
on inherent safety indexes. Based on these findings, the isobutylene
and t-butyl alcohol routes to MMA are found to have
the overall greenest attributes among the 18 routes examined.