Megan Entwistle, Maria Amos, and Paul Golubic
CHEM 0330 Organic Lab 1
Sodium Borohydride Reduction: Diphenylmethanol from Benzophenone
11/16/11
Introduction
Redox (shorthand for REDuction-OXidation) reactions are chemical reactions in which the oxidation state (or oxidation number) of atoms has changed. Oxidation can be observed through the loss of electrons or an increase in oxidation state by an atom, ion or molecule. Reduction describes the gain of electrons or decrease in oxidation state of an atom, ion or molecule. However, there are many processes that are classed as redox even though no electron transfer occurs, for example those reactions that involves covalent bonds.
Reduction reactions can be determined through three
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The amount of solvent is not crucial, but enough should be used to completely dissolve the reactants Hydrogenation is a process that creates hydrogen bonds on carbon molecules, usually a pair of hydrogen atoms. This process is done by treating hydrogen as a reducing chemical in a chemical reaction between hydrogen and another compound. In this hydrogenation process, the chemicals are usually accompanied with a catalyst. Catalysts are very much needed in this process to make it usable, without the presence of a catalyst this chemical reaction can only be possible at very high temperatures. Thus, in a laboratory setting, it is vital to have catalysts in this reaction. In short, hydrogenation has three components, unsaturated substrate, hydrogen (mostly in gaseous state), and a catalysts. The temperature of the reaction varies depending on the substrate and the activity of the catalyst. The substrate for hydrogenation is almost always alkenes that produce saturated alkanes as the end product. This chemical process is very selective due to the steric hindrance that plays a role in determining where exactly would the hydrogen atoms be placed. There are few catalysts, namely, platinum, nickel, palladium, rhodium, and ruthenium. These are considered very active catalysts as they are able to operate at lower temperatures. Hydrogenation
In part A, the Grignard reagent was created. Mg is added between the benzene ring and the bromine by means of a non-chain radical reaction. Initially, Mg donates and electron to bromide and heterolytically breaks the C-Br bond; therefore, this results in a carbon radical, Br - ion, and a Mg+ radical. Next, the carbon radical and the Mg+ radical bond together, and the Mg and Br - ionically bond together2. In the experiment, no initial color change to cloudy gray was observed. Eventually, it was decided to try and
The Purpose of this experiment is for the students to learn how to use sodium borohydride to reduce benzil to its secondary alcohol product via reduction reaction. This two-step reaction reduces aldehydes by hydrides to primary alcohols, and ketones to secondary alcohols. In order for the reaction to occur and to better control the stereochemistry and yield of the product, the metal hydride nucleophile of the reducing agents such as LiH, LiAlH4, or NaBH4 must be carefully chosen. Being that LiAlH4 and NaBH4 will not react with isolated carbon-carbon double bonds nor the double bonds from aromatic rings; the chosen compound can be reduce selectively when the nucleophile only react with
The Hydrogen Fuel Cell could revolutionize the world. This ingenious technology, which creates electricity from the chemical reactions of hydrogen and oxygen has, in its 150-year history, passed many of the critical tests along the path from invention to innovation. Recent developments in fuel cell technology and concurrent developments within the energy and automotive industries have brought the world to brink of the fuel cell age and the hydrogen economy.
In radical halogenations lab 1-chlorobutane and 5% sodium hypochlorite solution was mixed in a vial and put through tests to give a product that can then be analyzed using gas chromatography. This experiment was performed to show how a radical hydrogenation reaction works with alkanes. Four isomers were attained and then relative reactivity rate was calculated. 1,1-dichlorobutane had 2.5% per Hydrogen; 1,2-dichlorobutane had 10%; 1,3-dichlorobutane had 23%; and 1,4-dichlorobutane had 9.34% per Hydrogen.
Redox reactions are an important class of reactions in organic chemistry that involve the transfer of electrons from
Experiments 2-1 and 2-2 study the production of hydrogen gas by different chemical reactions. By using a hydrogen gas collection apparatus and the principles of chemistry, we were able to evaluate the data and reach our goal. Experiment 2-1 uses zinc, magnesium and aluminum and how much hydrogen gas they produce to predict the volume of hydrogen gas produced for different masses of each metal. In this experiment we see that each metal has an increasing amount of hydrogen gas as mass goes up, however each metal had different amount of hydrogen gas for the same mass. Zinc produced the least amount of hydrogen gas, then increasing with magnesium, and aluminum produced the highest amount. The
Halogenation is when one or more hydrogens in a compound are replaced with a halogen, for example fluorine, chlorine, bromine or iodine. In a halogenation of the alkane, the
82. Oxidation occurs when there is a removal of electrons and/or hydrogen atoms from a
Oxidation-reduction reactions can be used to stereochemically control and produce many different organic molecules. The oxidation step in this process increases the number of carbon oxygen bonds by losing a hydrogen and breaking
Like Photosynthesis, cellular respiration is also a redox reaction where glucose loses electrons and hydrogen atoms to produce carbon dioxide causing the glucose to become oxidized. At the same time, oxygen gains electrons and hydrogen atoms, reducing it to water.
The brewer jar has a high-vacuum pump that evacuates oxygen that gets replaced with a 95% mixture of nitrogen and 5% carbon dioxide. There are platinum catalysts in the jar lid that binds residual oxygen with hydrogen which forms water. The second is the GasPak system. The disposable hydrogen and carbon dioxide envelope generator. The system requires it to be in room temperature catalyst that doesn't need electrical activation to be used. Hydrogen reacts with oxygen to help yield water. The last technique is the chromium sulfuric acid method. Hydrogen is generated in a desiccator jar that reacts with 15% of sulfuric acid with chromium powder. Hydrogen evolves and gets forced out of the desiccator jar and gets replaced with hydrogen.
Hydrogen has already been under the micro scope for many years as an alternative fuel source to us because of its abundance and power. We have simply been lacking the
The oxidation reaction occurs as a two-step reaction. The first step involves the formation of chromate esters and the second step is an elimination reaction that will produce the carbonyl group necessary to make either a ketone or an aldehydes. The reaction is hallmarked by the breaking of a C-H bond and the formation of a C-O bond (James, 2014). Specifically when oxidizing alcohols, it is important to note that primary alcohols can be converted to aldehydes as well as completely to carboxylic acids, secondary alcohols are converted to ketones and no further, and tertiary alcohols cannot be oxidized. The oxidizing agent removes the hydrogen from the –OH group and the hydrogen from the C-H group attached to the –OH group in a compound. Tertiary alcohols cannot be oxidized because they lack the C-H bond that is present in both the oxidation of primary and secondary alcohols (Clark, 2003).
small, positively-charged proton with a negatively-charged electron orbiting very fast, a model analogous to the earth orbiting the sun, or the moon orbiting the earth. Fuel cells take advantage of this structure. Using a membrane and a catalyst, hydrogen is broken up into a proton and an electron. While there are many different membrane models for fuel cells, the most appropriate one for car travel is the Polymer Electrolyte Membrane (PEM, also called the Proton Exchange Membrane). It is called this because protons are able to easily pass through the membrane. However, because the membrane does not allow electrons to pass through it, the electrons take a detour through an electrical circuit to the other side of the cell. If hydrogen is supplied into the cell at a steady rate, the stream of electrons in the electrical circuit creates electric power. However, like all batteries, you need a positive end (cathode) and a negative end (anode); in other words, the hydrogen atoms must have a “reason” to make this electrical circuit. And what is this reason? Oxygen. With oxygen at the other end, hydrogen is more than willing to create this current so that it can bind and form H2O, or water on the other end.
Then, a shift is observed by one of the atoms to the carbocation. And finally, to stabilize the molecule, catalyst is then regenerated to yield the final product.