Cross-Metathesis approach to a,w-Bifunctional Compounds from Methyl Oleate and cis-2-Butene-1,4-diol

The cross metathesis (CM) of methyl oleate (1) and cis-2-butene-1,2-diol (2) was investigated to access alpha, omega-bifunctional compounds. The optimal CM conditions involve Stewart-Grubbs catalyst at 0 °C, delivering CM product 3 in excellent yield. 3 was converted, in a single step and in >90% yields, to alcohol 7, aldehyde 8, and olefin 10, the useful synthetic intermediates for many specialty chemicals, including PA11 precursor. A tandem CM/isomerization process was also demonstrated for the first time

Cultivation of Microalgae at Extreme Alkaline pH Conditions: A Novel Approach for Biofuel Production

A major challenge to the economic viability of outdoor cultivation of microalgae is the high cost of CO₂ supply, even when microalgae farms are co-located with point sources of CO₂ emissions. In addition, the global capacity for algae biofuel generation is severely restricted when microalgae farm locations are constrained by proximity to CO₂ sources along with the additional limitations of low slope lands and favorable climate. One potential solution to the impediments of CO₂ supply cost and availability is through cultivation of microalgae in highly alkaline pH solutions (pH >10) that are effective at scavenging CO₂ from the atmosphere at high rates. The extremely alkaline pH media would also mitigate culture crashes due to microbial contamination and predators. In this study, we report the indoor and outdoor phototrophic cultivation of a microalgae isolate (<i>Chlorella sorokiniana</i> str. SLA-04) adapted to grow in unusually high-pH environments. The isolate was cultivated in a growth medium at pH >10 without any inputs of concentrated CO₂. Both indoor and outdoor studies showed biomass and lipid productivities that were comparable to those reported for other microalgae cultures cultivated in near-neutral pH media (pH 7–8.5) under similar conditions. SLA-04 cultures also showed high lipid productivity and high glucose-to-lipid conversion efficiency when cultivated mixotrophically in the presence of glucose as an organic carbon source. From the energy content (calorific value) of the lipids produced and glucose consumed, a relatively high amount of lipid calories (0.62) were produced per glucose calorie consumed. In conclusion, our results demonstrate the feasibility of microalgae cultivation in extremely high-pH media (pH >10) as a novel strategy for biofuel production without dependence on concentrated CO₂ inputs

Flash Pyrolysis of Oleaginous Biomass in a Fluidized-Bed Reactor

In this study, flash pyrolysis was performed using milled soybean as a model substrate to assess the production of liquid fuels from oleaginous biomass feedstocks. A laboratory-scale fluidized-bed flash pyrolysis reactor that allowed rapid heat transfer to the biomass along with short vapor residence time was designed and constructed. Pyrolysis was performed between 250 and 610 °C with a vapor residence time between 0.2 and 0.3 s. At 550 °C or higher, nearly 70% of the initial feed mass as well as feed carbon was recovered in bio-oil. In addition, 90% of the feedstock lipids were recovered in the bio-oil at these pyrolysis conditions. The high liquid products yields were attributed to (1) the low secondary degradation of bio-oils due to the short vapor residence time and (2) the high recovery of liquids in a novel dry ice packed-bed condenser that provided a high surface area for condensation/​aggregation of dilute bio-oil vapors/​aerosols that were entrained in the carrier gas. The bio-oil from this study had higher C and H content, higher calorific value, and lower oxygen and water content than bio-oil from wood. These results show that high-quality bio-oil at high yield can be obtained from flash pyrolysis of oleaginous feedstock

Efficient Production of Alkanolamides from Microalgae

Fatty acid alkanolamides (FAAA) are lipid derivatives with industrial applications as biosurfactants and biolubricants. Although conventionally produced from vegetable oils, use of alternative renewable sources that do not compete with the food supply chain, such as microalgae, is desirable. We studied the production of FAAA through direct in situ amidation of algal biomass or by amidation of fatty acid methyl esters (FAME) recovered from in situ transesterification of algae. In situ transesterification resulted in spontaneous formation of a distinct FAME phase, which could be easily recovered and converted to FAAA. With this two-step transesterification-followed-by-amidation method, >95% of algal lipids were recovered as FAAA products. In situ amidation did not result in a separate product phase, likely because of the amphiphilic nature of the product. However, extraction with ethyl acetate allowed recovery of nearly 90% of the biomass lipids as FAAA after in situ amidation