Transitioning from a conventional refinery to a biorefinery has led to the search for biomass resources that can be processed to generate both energy and valuable products for the economic viability of the biorefinery. Different types of first- and second-generation biomass have been developed and investigated since the 20th century. These include sugar crops, starch crops, vegetable oils, and lignocellulose (residue and by-products). Issues around the consequent losses of food and fiber production has led to marine resources, the third-generation biomass. Marine biomass such as microalgae and seaweeds, are more sustainable and environmentally friendly as they can be grown in non-arable land, use less water, and capture carbon dioxide. Reported seaweed investigations for both energy production and valuable chemical products are limited. Recent work has focused on the production of cellulose-derived platform chemicals. This thesis reports on investigations of the conversion of seaweed carbohydrates into platform chemicals (Part 1, Chapters 2 and 3) using H2SO4-catalyzed pyrolysis in polyethylene glycol (PEG). This methodology is again used on readily available carbohydrates and protected carbohydrates derivatives as substrates for the generation of chiral feedstocks (Part 2, Chapter 4).