Dr. Srećko Marač (1921-1985) : liječnik- psihijatar/psihoterapeut i pjesnik

Srećko Marač (Sušak, 1921. – Zagreb, 1990.). Nakon završetka sušačke gimnazije studira medicinu u Zagrebu i Padovi. Tijekom Drugoga svjetskog rata prekida studij i odlazi u NOR. Nakon rata završava studij u Zagrebu. Kao vojni liječnik radi u Bjelovaru i u Vojnoj bolnici u Zagrebu. Specijalizira psihijatriju i radi kao psihoterapeut u nekadašnjem Centru za mentalno zdravlje u Zagrebu.Godine 1973. objavljuje u vlastitom izdanju prvu zbirku pjesama – vlastiti izbor iz dugogodišnjeg rada – pod naslovom "Pjesme". Cilj je ovoga rada napisati cjelovitiji osvrt na tu zbirku pjesama izdanu 1973. po vlastitom izboru i nakladi. Gledalo se analizirati strukturu/kompoziciju zbirke, sadržaje, ugođaj i komunikativnost pojedinih njezinih dijelova. Kompozicijski je zbirka strukturirana u pet dijelova: Ad tyrannos, Iz partizana, Lutanja/traženja/snovi…, Satire i kušanja humora, More/brda i domovina. Umjesto zaključka valjalo bi se potruditi da ovaj liječnik-pjesnik, poeta neprijeporne književne ljepote i osoba puna ljudske dobrote, ne bude zaboravljen

Selective Electrochemical Conversion of Glycerol to Glycolic Acid and Lactic Acid on a Mixed Carbon-Black Activated Carbon Electrode in a Single Compartment Electrochemical Cell

In recent years, the rapid swift increase in world biodiesel production has caused an oversupply of its by-product, glycerol. Therefore, extensive research is done worldwide to convert glycerol into numerous high added-value chemicals i.e., glyceric acid, 1,2-propanediol, acrolein, glycerol carbonate, dihydroxyacetone, etc. Hydroxyl acids, glycolic acid and lactic acid, which comprise of carboxyl and alcohol functional groups, are the focus of this study. They are chemicals that are commonly found in the cosmetic industry as an antioxidant or exfoliator and a chemical source of emulsifier in the food industry, respectively. The aim of this study is to selectively convert glycerol into these acids in a single compartment electrochemical cell. For the first time, electrochemical conversion was performed on the mixed carbon-black activated carbon composite (CBAC) with Amberlyst-15 as acid catalyst. To the best of our knowledge, conversion of glycerol to glycolic and lactic acids via electrochemical studies using this electrode has not been reported yet. Two operating parameters i.e., catalyst dosage (6.4–12.8% w/v) and reaction temperature [room temperature (300 K) to 353 K] were tested. At 353 K, the selectivity of glycolic acid can reach up to 72% (with a yield of 66%), using 9.6% w/v catalyst. Under the same temperature, lactic acid achieved its highest selectivity (20.7%) and yield (18.6%) at low catalyst dosage, 6.4% w/v

Preliminary study of electrochemical conversion of glucose on novel modified nickel electrodes

International audienceGluconic acid and sorbitol are among the value-added chemicals that can be derived from biomass. Nowadays, these compounds are typically produced through biotechnological processes, but electrochemical methods offer numerous advantages over alternative approaches. While studies have extensively explored metals like copper, palladium, gold, and platinum, nickel has received relatively limited attention in this context. Notably, nickel exhibits electrochemical activity suitable for organic electrosynthesis. This work has been achieved with 5-h long-term electrolysis, glucose as a reactant, utilizing modified nickel electrodes in a KOH solution. While these studies achieved substantial conversion rates, the selectivities and Faraday efficiencies toward gluconic acid and sorbitol remained comparatively low. The long-term electrolysis of glucose using modified nickel electrodes resulted in the identification of various side products. These include formic acid, oxalic acid, glycolic acid, tartronic acid, glyceric acid, and arabinose

Kinetics and hydrodynamics of Candida antartica lipase-catalyzed synthesis of glycerol dioleate (GDO) in a continuous flow packed-bed millireactor

Diacylglycerols (DAG) have been widely used in many industries due to their remarkable capabilities as emulsifiers and stabilisers. However, developing a sustainable and an effective synthesis method for DAG remains a challenge. Continuous flow bio-reactor is recognized to be more productive, controllable, and reliable instrument for developing green and intensified processes. In this work, a continuous flow packed bed millireactor was employed for the synthesis of glycerol dioelate (GDO) catalyzed by immobilized lipase namely Candida antartica. Experiments were carried out to evaluate the kinetic parameters as well as to assess the internal and external mass transfer limitations. Using one-factor-at-a-time variables method, maximum oleic acid conversion and GDO selectivity were achieved at 85% and 74% respectively, at 0.15 g of lipase, 77 min of residence time with 1.6:1 molar ratio of oleic acid/glycerol. Hydrodynamic studies showed that the esterification reaction is kinetically controlled and unaffected by external and internal mass transfer. Employing Lilly–Hornby model for kinetic evaluation, K m values increased with increasing flow rates, whereas, V max appeared to be flow rate independent. Reusability tests revealed that the activity of immobilized lipase remained the same after 9 successive reaction cycles. At 11 days of operation, the stability of the lipase in the continuous packed bed millireactor decreased only 5–7%, indicating satisfying operational results and recyclability. This work may promote the enzymatic engineering synthesis of DAG, facilitating the creation of a cleaner and safer process. It has the potential to broaden the application of enzymes in continuous flow micro or millireactors