Search results
Results from the WOW.Com Content Network
USP grade is equivalent to the ACS grade for many drugs. NF grade is a purity grade set by the National Formulary (NF). NF grade is equivalent to the ACS grade for many drugs. British Pharmacopoeia: Meets or exceeds requirements set by the British Pharmacopoeia (BP). Can be used for food, drug, and medical purposes, and also for most laboratory ...
Food grading involves the inspection, assessment and sorting of various foods regarding quality, freshness, legal conformity and market value. [1] [2] Food grading is often done by hand, in which foods are assessed and sorted. [1] [2] Machinery is also used to grade foods, and may involve sorting products by size, shape and quality.
The IUPAC acknowledges the three divergent definitions of carbonium ion and urges care in the usage of this term. For the remainder of this article, the term carbonium ion will be used in this latter restricted sense, while non-classical carbocation will be used to refer to any carbocation with C–C and/or C–H σ-bonds delocalized by bridging.
The 2-norbornyl cation is one of the best characterized carbonium ion. It is the prototype for non-classical ions. As indicated first by low-temperature NMR spectroscopy and confirmed by X-ray crystallography, [1] it has a symmetric structure with an RCH 2 + group bonded to an alkene group, stabilized by a bicyclic structure.
Modified starches are used in practically all starch applications, such as in food products as a thickening agent, stabilizer or emulsifier; in pharmaceuticals as a disintegrant; or as binder in coated paper. They are also used in many other applications. [2] Starches are modified to enhance their performance in different applications.
The Food Protection Committee started in 1961 to provide objective quality standards for food-grade chemicals. Parts of the first edition were published in loose-leaf form between 1963 and 1966. The scope of the first edition is limited to substances amenable to chemical characterization or biological standardization which are added directly to ...
Compared to a ketone, the polarization of an oxocarbenium ion is accentuated: they more strongly resemble a "true" carbocation, and they are more reactive toward nucleophiles. In organic reactions, ketones are commonly activated by the coordination of a Lewis acid or Brønsted acid to the oxygen to generate an oxocarbenium ion as an intermediate.
In organic chemistry, a carbanion is an anion in which carbon is negatively charged. [1] [failed verification]Formally, a carbanion is the conjugate base of a carbon acid: . R 3 CH + B − → R 3 C − + HB