Recebido em 4/7/13; aceito em 30/8/13; publicado na web em 18/9/13 CHEMISTRY AND SUSTAINABILITY: NEW FRONTIERS IN BIOFUELS. This contribution discusses the state of the art and the challenges in producing biofuels, as well as the need to develop chemical conversion processes of CO 2 in Brazil. Biofuels are sustainable alternatives to fossil fuels for providing energy, whilst minimizing the effects of CO 2 emissions into the atmosphere. Ethanol from fermentation of simple sugars and biodiesel produced from oils and fats are the first-generation of biofuels available in the country. However, they are preferentially produced from edible feedstocks (sugar cane and vegetable oils), which limits the expansion of national production. In addition, environmental issues, as well as political and societal pressures, have promoted the development of 2 nd and 3 rd generation biofuels. These biofuels are based on lignocellulosic biomass from agricultural waste and wood processing, and on algae, respectively. Cellulosic ethanol, from fermentation of cellulose-derived sugars, and hydrocarbons in the range of liquid fuels (gasoline, jet, and diesel fuels) produced through thermochemical conversion processes are considered biofuels of the new generation. Nevertheless, the available 2 nd and 3 rd generation biofuels, and those under development, have to be subsidized for inclusion in the consumer market. Therefore, one of the greatest challenges in the biofuels area is their competitive large-scale production in relation to fossil fuels. Owing to this, fossil fuels, based on petroleum, coal and natural gas, will be around for many years to come. Thus, it is necessary to utilize the inevitable CO 2 released by the combustion processes in a rational and economical way. Chemical transformation processes of CO 2 into methanol, hydrocarbons and organic carbonates are attractive and relatively easy to implement in the short-to-medium terms. However, the low reactivity of CO 2 and the thermodynamic limitations in terms of conversion and yield of products remain challenges to be overcome in the development of sustainable CO 2 conversion processes.Keywords: biofuels; biomass; CO 2 .
INTRODUÇÃOA Sociedade Brasileira de Química (SBQ), sempre atenta ao seu papel de discutir e propor soluções para temas de interesse nacional relacionados à área de Química, vem desenvolvendo inúmeras iniciativas, que também visam induzir políticas de C&T de interesse geral. O Censo da Química no País 1 é uma das mais recentes iniciativas, que visa debater com a comunidade assuntos estratégicos de interesse do país por meio de position papers, que descrevem a situação e desafios a serem vencidos em diversos temas centrais. A questão da energia é um dos temas centrais citados e no qual o presente artigo pretende contribuir para o debate, colocando a questão dos biocombustíveis e a utilização racional do CO 2 em contraponto aos combustíveis de origem fóssil, que além de finitos, causam sérios problemas ambientais.O século XX associou a Química à poluição ambiental...