Fluorene Chromatography

In this experiment, 0.95 mL of phosphoric acid, 0.75 mL of 2-methylcyclohexonal, and Drierite are added to a Hickman still. The prepared Hickman still is submerged halfway into a preheated sand bath. The temperature range was kept above 140 ˚C but below 165˚C to prevent the product from evaporating. The product collected in the ring of the Hickman still for about twenty minutes. Once the reaction was complete, the product was transferred into a pre-weighed vial using a slant Pasteur pipette. The percent yield of the recovered product is calculated, and IR spectroscopy and gas chromatography are used to analyze the purity and percent composition of different alkene

The acidity and vinegar, the type of vinegar we used was Kroger distilled white vinegar, and the acidity of the vinegar was 5%

The purpose of this experiment was to learn about metal hydride reduction reactions. Therefore, the sodium borohydride reduction of the ketone, 9-fluorenone was performed to yield the secondary alcohol, 9-fluorenol. Reduction of an organic molecule usually corresponds to decreasing its oxygen content or increasing its hydrogen content. In order to achieve such a chemical change, sodium borohydride (NaBH4) is used as a reducing agent. There are other metal hydrides used in the reduction of carbonyl groups such as lithium aluminum hydride (LiAlH4). Nevertheless, the latter is not used in this experiment since it is very reactive and extremely flammable. On the contrary, NaBH4 is relatively mild and it can be used with protic solvents.

The goal of this experiment was to isolate three different molecules (acidic, basic, and neutral) from a mixture and identify their molecular structure. This was accomplished by using acid/base liquid extraction and H NMR analysis.

Dalton’s law, as described before, states that the sum of the partial pressures of each component in a solution – two or more volatile compounds – is equal to the total pressure. As this now includes more than one compound when separating volatile substances from each other, fractional distillation must be used. Fractional distillation, which can be viewed as a series of simple distillations, is a method used to separate volatile impurities from its solvent. The main difference is that a column is introduced between distillation flask and head to separate the liquids from each other. This column – of a large surface area with glass or ceramic – provides ample contact between the vapor and liquid phases. A temperature gradient is formed because the head of the system is now further from the flask. Factors that affect the temperature gradient include the rate of heating and vapor removal from the system’s stillhead. Upon heating, the vapor of compound A rises, reaching a distance at which it no longer has enough energy to maintain its gaseous form; at this point, the molecules re-enter the liquid state. This process of rising up, condensation, and revaporization eventually results in vapor comprising 100% of substance A. This process is then repeated at the boiling point of substance B. The efficiency of this process is reflected by the reflux ratio, which reveals how many condensate drops reenter the stillpot for every distillate drop

Bromination is a type of electrophilic aromatic substitution reaction where one hydrogen atom of benzene or benzene derivative is replaced by bromine due to an electrophilic attack on the benzene ring.

In nucleophilic substitution reactions, there are two possibilities, either Sn1 or Sn2. In this particular experiment, an Sn2 reaction

The reduction of 9-fluorenone experiments in period 8 is a reduction reaction of double bonds, specifically a reduction of a carbonyl compound to prepare an alcohol, 9-flurenol is this experiment. Just to reiterate what a carbonyl is, a carbonyl is a compound that has a carbon double bonded to an oxygen. Since the main reaction behind this week’s experiment is a reduction reaction, it is important to learn and understand how and what takes place in it. In general terms, a reduction is a gain of electrons, opposite of oxidation, and an increase in carbon to hydrogen bonds caused by adding hydrogen atoms across double and triple bonds. This is not necessarily true in organic chemistry because the above process usually takes place on neutral atom or an ion but in this case carbon does not gain the electrons because a covalent bond is made. One way to tell if the reaction that has taken place is a reduction or not is by checking if the oxidation number of the carbon has decreased.

(0.0035 moles of CaCl2) x (1 mole Ca(OH)2/ 1 mole of CaCl2) = 0.004 moles of Ca(OH)2

The methods used sequentially for purification of aqueous extract were i) Ammonium Sulfate Precipitation, ii) dialysis and iii) Ion-exchange chromatography on DEAE-Cellulose columns.

The main objective of this experiment was to synthesize cyclohexanone from the starting reactant cyclohexanol using oxidation techniques. The mechanism of this oxidation reaction was not fully established but scientists today were able to create a possible mechanisms for the synthesis of cyclohexanone. The mechanisms involved were known that it does not involve free radicals and that the yields were better in acidic rather than basic conditions (Experiment 8 of myweb.brooklyn.liu.edu Laboratory Manuals, n.d.). The figures below explain one of the possible mechanisms of the synthesis of cyclohexanone.

Chromatography is a laboratory technique for the separation of a mixture. The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase. The various constituents of the mixture travel at different speeds, causing them to be separated. In fact, the separation is based on differential partitioning between the mobile and stationary phases [1].

The fluorine has the special topic of interest among the chemists as its introduction into the organic molecules leads to a dramatic changes in their physical and chemical properties.[4] The recent activities show a remarkable growth in fluorine chemistry as the chemists practiced to do polishing the organic molecules with fluorine to improve their properties, leading to widespread applications in medicinal,[4b,c,5] agrochemicals,[6]

The unknown concentration of benzoic acid used when titrated with standardized 0.1031M NaOH and the solubility was calculated at two different temperatures (20◦C and 30◦C). With the aid of the Van’t Hoff equation, the enthalpy of solution of benzoic acid at those temperatures was determined as 10.82 KJ. This compares well with the value of 10.27KJ found in the literature.

The term chromatography actually means colour writing, and signifies a technique by which the substance to be examined is placed in a vertical glass tube containing an adsorbent, the different segments of the substance traveling through the adsorbent at distinctive rates of velocity, according to their degree of attraction to it, and producing bands of colour at different levels of the adsorption column. The substances least absorbed emerge earliest; those more strongly absorbed emerge later. (Wixom et al., 2011)