Biodiesel production by two-stage transesterification with ethanol by washing with neutral water and water saturated with carbon dioxide.

Industrial production of ethyl esters is impeded by difficulties in purifying the product due to high amounts of soap formed during transesterification. A simple biodiesel wash process was developed that allows successful purification of samples containing high amounts of soap. The key step was a first washing with neutral water, which removed the soaps without increasing the acidity or affecting the process yield.

Biodiesel production by two-stage transesterification with ethanol.

A two-stage process consisting of two reactions steps with glycerin separation and ethanol/catalyst addition in each of them was optimized for ethyl esters production. The optimal reaction temperature was 55 °C. At an ethanol/oil molar ratio of 4.

Ethyl ester production by homogeneous alkaline transesterification: influence of the catalyst.

In this work, the process for ethyl ester production is studied using refined sunflower oil, and NaOH, KOH, CH(3)ONa, and CH(3)OK, as catalysts. In all cases, the reaction is carried out in a single reaction step. The best conversion is obtained when the catalyst is either sodium methoxide or potassium methoxide.

Comparison among patterns of macromolecular synthesis in Escherichia coli B/r at growth rates of less and more than one doubling per hour at 37 degrees C.

In Escherichia coli B/r, the relationship between the patterns of chromosome replication and of synthesis of envelope components differs at various growth rates. At growth rates greater than 1.0 doubling per h at 37 degrees C, the average mass and age at initiation of rounds of chromosome replication are similar to those at increase in incorporation of precursors into a major outer membrane protein and phosphatidylethanolamine.