Carbon Dioxide as Feedstock for Polymers and Fuels – a challenge for sustainable chemistry

Bayer Material Science exhibited polyurethane blocks at ACHEMA, which were made from CO2 polyols. CO2 replaces some of the mineral oil use. Industrial manufacturing of foams for mattresses and insulating materials for fridges and buildings is due to start in 2015.

PPC as a softener for bioplastics

Many bio-based plastics, e.g. PLA and PHA, are originally too brittle and can therefore only be used in conjunction with additives for many uses. Now a new option is available. They can cover an extended range of material characteristics through combinations of PPC with PLA or PHA. This keeps the material biodegradable and translucent, and it can be processed without any trouble using normal machinery. The vacuum cleaner casings that Bosch Siemens Household Appliances (BSH) displayed at ACHEMA are predominantly made of BASF’s PPC and PHA and are intended as a substitute for the bulk plastic ABS. The first internal life-cycle analysis studies demonstrate the material’s clear advantages. PPC/PLA combinations were used in fridge compartments.

Fuel from wind power, solar power and CO2

An outside energy source is required if CO2 is to be used as fuel. The major option here is to use surplus wind and solar power, which frequently occurs in Germany. Storage is a central concern with the expansion of renewable energy.
If the surplus electricity is used to produce hydrogen (H2) from water, this can then be converted into various fuels in conjunction with CO2. The first reaction is that of H2 with CO2 to form methane (CH4), which can then fed into the gas network. Further chemical processes lead to methanol, petrol, diesel and kerosene. The high temperature steam electrolysis that is being optimized in the BMBF project now achieves a 70% efficiency level (electricity to hydrogen).
In 2011 a consortium of businesses in Iceland began building the first commercial plant, which will produce 5 million litres of methanol per year from CO2. That would cover 2.5% of Iceland’s fuel needs.

CO2 as growth substrate for algae and bacteria

However, the world’s largest use of CO2 takes every day right in front of our eyes. With the help of photosynthesis (and with the action of sunlight), plants convert carbon dioxide into sugar, which they then use to produce all the important bio-molecules. This can also be commercially exploited: in large-scale reactors algae are gassed with carbon dioxide from power stations and then produce biomass.