Acid hydrolysis

Summary

In organic chemistry, acid hydrolysis is a hydrolysis process in which a protic acid is used to catalyze the cleavage of a chemical bond via a nucleophilic substitution reaction, with the addition of the elements of water (H2O). For example, in the conversion of cellulose or starch to glucose. For the case of esters and amides, it can be defined as an acid catalyzed nucleophilic acyl substitution reaction. The term is also applied to certain nucleophilic addition reactions, such as in the acid catalyzed hydrolysis of nitriles to amides. Acid hydrolysis does not usually refer to the acid catalyzed addition of the elements of water to double or triple bonds by electrophilic addition as may originate from a hydration reaction. Acid hydrolysis is used to prepare monosaccharide with the help of acids, such as: Hydrochloric acid Sulfuric acid Trifluoroacetic acid Formic acid Nitric acid Acid hydrolysis can be utilized in the pretreatment of cellulosic material, so as to cut the interchain linkages in hemicellulose and cellulose.

Official source

https://en.wikipedia.org/wiki/Acid_hydrolysis

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Related publications (1)

Selection of Water-Soluble Chitosan by Microwave-Assisted Degradation and pH-Controlled Precipitation

Sandrine Gerber, Yann Lavanchy, Céline Marie Anne Journot, Laura Camille Louise Nicolle

In the field of gene therapy, chitosan (CS) gained interest for its promise as a non-viral DNA vector. However, commercial sources of CS lack precise characterization and do not generally reach sufficient solubility in aqueous media for in vitro and in vivo evaluation. As low molecular weight CS showed improved solubility, we investigated the process of CS depolymerization by acidic hydrolysis, using either long time heating at 80 °C or short time microwave-enhanced heating. The resulting depolymerized chitosan (dCS) were analyzed by gel permeation chromatography (GPC) and 1H nuclear magnetic resonance (NMR) to determine their average molecular weight (Mn, Mp and Mw), polydispersity index (PD) and degree of deacetylation (DD). We emphasized the production of water-soluble CS (solubility > 5 mg/mL), obtained in reproducible yield and characteristics, and suitable for downstream functionalization. Optimal microwave-assisted conditions provided dCS with a molecular weight (MW) = 12.6 ± 0.6 kDa, PD = 1.41 ± 0.05 and DD = 85%. While almost never discussed in the literature, we observed the partial post-production aggregation of dCS when exposed to phase changes (from liquid to solid). Repeated cycles of freezing/thawing allowed the selection of dCS fractions which were exempt of crystalline particles formation upon solubilization from frozen samples.

2020

Related concepts (3)

Acid hydrolysis

Cellulose

Cellulose is an organic compound with the formula (C6H10O5)n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. Some species of bacteria secrete it to form biofilms. Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, and that of dried hemp is approximately 57%.

Ester

In chemistry, an ester is a compound derived from an acid (organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (). Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well (e.g. amides), but not according to the IUPAC.