Isotopes of carbon

a) Heckel equation In 1961, Heckel proposed the most widely used equation describing pharmaceutical powder behavior in compaction. It was initially used to study the densification of ceramics and its correlation with pressure. It a first order process where powder pores elimination rate is correlated to the number of pores present. The rate of volume reduction increases as the number of pores decrease. Heckel equation relates the density, pressure and the pore fraction of the powder [16],.…

Schiff Bases: Schiff bases are amongst the important class of drugs containing imine or azoethine (-C=N-) moiety,have been obtained by the condensation of primary amines and carbonyl compounds.It was first time presented by the Hugo schiff (Cimerman et al, 2000). Schiff bases are one of the most important class of organic drugs widely used in variety of different fields such as analytical, biological, and inorganic chemistry.The schiff bases heve been designed to synthesize more and more novel…

In this work we have prepared ceramic-polybenzoxazine composites based on poly(P-ddm) as matrix reinforced by 0, 3, 5, 7, 10, 15, and 20 wt.% of GX-540 silane-treated nano-Cr2O3 filler via a solution blending method in THF. These nanocomposites are used as new organic coating materials. The effect Cr2O3 nanofillers inclusion on the viscoelastic properties of poly(P-ddm) is studied using dynamic mechanical analysis (DMA). Figure 76 illustrates the change in the storage modulus at 50oC and…

gently for 5 minutes. Allow the mixture to cool slightly and filter by gentle suction and wash it 3-4 times with CCl4. Recrystallize it from the boiling water. Mechanism: The Reaction involves: Nucleophilic attack of NH2 of glucine on the carbonyl carbon of benzoyl chloride Rearrangment and deprotonation (elimination of HCl molecule) to give benzoyl glycine Step II: Preparation of 4-Benzylidine-2-phenyl-oxazol-5-one from benzoyl…

In September of 1985 Kroto, Heath, O’Brien, Curl, and Smalley were investigating sources of the long carbon chain molecules in the interstellar medium and how they might be related to soot formation.1 Smalley developed a laser vaporization cluster beam apparatus that allowed for the mass-spectrometric study of stable clusters formed in a helium-entrained plasma produced by a pulse of laser aimed on at a solid target.2 This experimental technique was a very important discovery to cluster science…

Diamonds. These small and rare rocks have been considered prized possessions throughout the ages. Diamonds are as old as the earth itself, and ever since their discovery they have captivated humans. Diamonds have come to represent many things, but in this paper, I will focus on power. I will track a certain diamond through its’ dated 350-year period, and use it to understand the individuals who owned it and the power it gave them. The diamond I refer to is the hope diamond. The Hope diamond is…

In Experiment 12B we used an umpolung reagent in an umpolung synthesis to synthesize benzoin from benzaldehyde. Umpolung synthesis is a synthetic approach that allows us to switch the identity of a reacting species. For example, the normal chemical reactivity of a nucleophile can be switched to one of an electrophilic compound. Two common agents are cyanide and thiamine (Vitamin B). The mechanisms for both agents are the same. In this experiment, thiamine was used to turn benzaldehyde, an…

Distant lands, by Tim Winton is a short novel that has resonated with me as a reader by its ideas expressed on the subject matter of family, multiculturalism and human desires. This is done through the language convention: simple sentences, point of view and the actions of its main character Fat Maz. Fat Maz is the main protagonist who is used to present the idea of family that has evoked in me a sense of appreciation and gratefulness towards my parents for the things they have done for me since…

Why small covalent substances have different properties from macro molecules? • Simple covalent substances will only contain a few atoms that are held by strong covalent bonds for example co2 the molecules contain one atom of carbon that is bonded with 2 oxygen atoms. The intermolecular forces causes the small covalent structures to have a low melting/boiling points, they don’t conduct electricity because they don’t have any free electrons or an electric charge overall. • Macro molecules will…

The development of simple methods for generating molecular complexity with defined stereochemistry from easily accessible starting materials became significant and fascinating over last few decades. A simple methoxyphenol is found to be most appropriate precursor for generating wide range of complex cyclic and acyclic architectures. Several chemical1-5 and electrochemical methods6 have been used for the umpolung of electron-rich nucleophilic 2-methoxyphenols and 4-methoxyphenols to electrophilic…