Discussion: 1. The Diels alder reaction has to be heated slowly to 60-70 degrees Celsius because if it is heated too quickly and the temperature gets too high the 2,3-dimethyl-1,3-butadiene will boil. A round bottom flask was attached to a water condenser to prevent any product from boiling and evaporating out during the heating process. For the hydrolysis part of the experiment the temperature needed to be 60-80 degrees Celsius to melt the cyclic anhydride but also prevent the reaction from boiling and losing product from evaporation. Lastly the final product crystals were not washed with hot water because it would have melted the crystal thus cold water was used.
The aqueous layer was drained, and NaOH was added to neutralize the solution, and deprotonate the conjugate acid to reform the original base, which, as an organic base, was mostly insoluble in an aqueous solution, and precipitated out. Similarly, NaOH deprotonated the organic acid to form a polar water soluble conjugate base. When HCl was added to neutralize the solution, the conjugate base was reprotonated, and the largely insoluble organic acid precipitated out. Sodium sulfate crystals were added to the neutral compound in the organic solvent, because of their hygroscopic property, in order to remove all water from the ethyl acetate solution. The crystals were then filtered out using a piece of cotton with a glass funnel, which ideally trapped and removed all sodium sulfate
6(c) The answers would not change because the bond angles between Cl-C-Cl and H-C-C do not affect the angle of rotation. 7(a) There are seven fluorine environments. 7(b) For a compound a dipole there must be present of partial negative and positive charges. Naphthalene (A) lacks a centre of symmetry (chiral carbon) which is attached to compound or atom with partial negative charge. In compound B, there are two positions of the centre of symmetry.
Diethylthiourea, 0.1 wt%, may also be added as a corrosion inhibitor when using CITROX with carbon steel systems. Also ferric nitrate can be used as a corrosion inhibitor [34, 35]. Organic acids dissolve and complex the corrosion products and the chelating agent chemically bind the released or dissolved corrosion products. The concentration ratio of oxalic acid to dibasic ammonium citrate must be less than or equal to 0.5 to prevent secondary film formation. This is important because citrate ions complex iron and inhibit the formation of an oxalate precipitate.
From the bromination of 0.05g aniline, 0.156g of the product was collected. The percent yield was calculated to be 88.1%. Some amount of the product was lost when transferring the product from the Buchner funnel to the balance to measure its mass. To ensure the formation of the desired product, melting point of the product was measured to be 119.8-121.90c, which is in the range of the normal melting point of 2,4,6-tribromoanilne, 120-1220c. Thus, the product was indeed
This will make the limestone lose the carbon dioxide and increase the purity of the calcium carbonate. Secondly, filter this mixture to remove the remaining silica and other insoluble materials. Next, add oxalic acid (H2C204), to the limestone powered. This mixture will create a calcium oxalate ( CaC2O4), and aqueous carbonic acid ( H2C03), according to this formula: CaC03 + H2C2O4 -> CaC2O4 + H2CO3. The next step is to rinse the calcium oxalate and sprinkle some deionized water and pour it into a beaker.
So, as the bond rotation of butane continues, the molecule will reach the conformation situation of staggered and gauche. At this conformation, the butane also achieved the energy minima as it does not achieve the eclipsed conformation. The arrangement is staggered as the two methyl groups is 60°apart. This gauche conformation has the energy of 3.8 kJ/mol. The steric strain is arose due to the hydrogen atoms of the methyl groups are near to each other in the gauche conformation.
The resulting hexahydropyrimidines(b) need not to be isolated and can be converted directly into DHPMs. This method works particularly well for aliphatic aldehydes and thiourea and produces high overall yields of the desired compound.21 Scheme-4: There are several combinatorial approaches towards DHPMs have been advanced using solid phase. In the solid-phase modifications of the Biginelli condensation, the urea component is linked to the solid support via the amide nitrogen, which invariably leads to the formation of N1-functionalized
It helps to prevent strokes, heart attacks and blood clot formation. It can be produced from salicylic acid and acetic anhydride, with acetic acid as its by-product. However, salicylic acid consists of the phenolic and carboxylic acid groups which are way too acidic for the stomach lining. Thus, acetylsalicylic acid (aspirin) was refined to become a more effective substitute. Theories In this experiment set-up, acetic anhydride is added to salicylic acid in the presence of a catalyst, concentrated sulphuric acid.
It is to prevent the cell from washing away during the staining and washing process. Then, it is air dried and followed by fixing it with flame from Bunsen burner. After fixing the smear, it must be stained using Gram staining solution, firstly crystal violet solution was flood onto it, and allowed for 1 minute, then wash off with tap water. Then, flood the slide with iodine solution for 1 minute and wash it off with tap water again. The formation of a dye-iodine complex will occur in the cytoplasm.