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Research laboratory 6: Electrophilic Aromatic Replacement

 Lab six: Electrophilic Fragrant Substitution Composition

Research laboratory 6: Electrophilic Aromatic Substitution(1) Nitration of Methyl Benzoate(2) Synthesis of 1, 4-Di-t-butyl-2, 5-dimethoxybenzene byFriedel-Crafts Alkylation of 1, 4-DimethoxybenzenePurpose1)To carry out the nitration of methyl benzoate, and then determine the major product formed (position at which nitro-group substitution takes place) by thin-layer chromatography (TLC), the percent yield and the melting point selection.

2)To synthesize 1, 4-Di-t-butyl-2, 5-dimethoxybenzene simply by Friedel-Crafts Alkylation of 1, 4-Dimethoxybenzene, and then decide the percent yield and melting point range.

Procedure*Please refer to invisalign handout six and Macroscale and Microscale Organic Experiments (Williamson, 2003).

* Portion II with the experiment (Synthesis of 1, 4-Di-t-butyl-2, 5-dimethoxybenzene simply by Friedel-Crafts Alkylation of 1, 4-Dimethoxybenzene) was carried out by Ashley and me. Part I (nitration of methyl benzoate) was carried out by Jenny.

Physical Variety TableType of substanceMolecular FormulaMolecular Weight (g/mol)Density(g/cm3)M. P. (oC)B. P. (oC)Methyl benzoateC8H8O2136. 161. 094-15198-200Methyl 2-nitrobenzoateC8H7NO4181. 141. 289-13104Methyl 3-nitrobenzoateC8H7NO4181. 14-78-80289Methyl 3, 5-dinitrobenzoateC8H6N2O6226. 14544-106-109-Methyl 4-nitrobenzoateC8H7NO4181. 15-94-96-1, 4-DimethoxybenzeneC8H10O2138. 161. 0555-582131, 4-Di-t-butyl-2, 5-dimethoxybenzeneC16H26O2250. 37-104-105-2-methyl-2-propanolC4H10O74. 12-25. 482. 4Hazard Concentrated sulfuric acid and nitric chemical p are highly rust.

ObservationPart II Friedel-Crafts AlkylationThe concentrated sulfuric acid employed was yellowish. 1, 4-Dimethoxybenzene was in white-colored crystal kind. The t-butyl alcohol solidified in room heat, so it had taken a while to heat up and return to liquid kind. After centered sulfuric acidity was added to the t-butyl alcohol, acetic acid and 1, 4-Dimethoxybenzene combination, the solution started to be light darkish in color. After heating for a while, light precipitate could possibly be observed in the bottom of the pipe. After normal water was added, the white-colored precipitate dissolved and the option turned milky. The crystals obtained following recrystallization are in form of large slideshow. They are grinded into powdery or more compact granules pertaining to melting stage test.

DataPart IMass of methyl benzoate = 0. 30gMass of recrystallized merchandise = 0. 28436gMelting Point Range of nitration product = 75 occitan - 83 oCChemical CompoundsDistance from N to areas (cm)Distance from B to SF(cm)Distance from B to spots (cm)/Distance from M to SF (cm)Retention FactorRfMethyl benzoate1. 684. 501. 68/4. 500. 37(ortho) Methyl 2-nitrobenzoate1. 304. 521. 30/4. 520. 29(meta) Methyl 3-nitrobenzoate1. 804. 501. 80/4. 500. 40Methyl 3, 5-dinitrobenzoate1. 304. 401. 30/4. 500. 30(para)Methyl 4-nitrobenzoate1. 804. 301. 80/4. three hundred. 42Unknown Product1. 804. 301. 80/4. three hundred. 42Table one showing the Retention factor of not known nitration merchandise with comparison to standard valuesB = baselineSF sama dengan solvent frontDrawing of TLC PlatesPlate #1: Platter #2: Key1 = Methyl benzoate2 sama dengan Methyl 2-nitrobenzoate3 = Methyl 3-nitrobenzoate5 sama dengan Methyl 3, 5-dinitrobenzoate4 = Methyl 4-nitrobenzoateP = Unfamiliar nitration ProductPart IIMass of just one, 4-Dimethoxybenzene = 0. 1220gMass of recrystallized product (1, 4-Di-t-butyl-2, 5-dimethoxybenzene)= 0. 085gMelting Point Selection of alkylation item = 97oC -102 oCResult & CalculationPart IBased about data via both burning point test and TLC, the nitration system is likely to be methyl 3-nitrobenzoate (details in conversation part).

Theoretical Mass1 mole of methyl benzoate produced 1 gopher of methyl 3-nitrobenzoate: Skin mole of methyl benzoate = 0. 3g/136. 16 g mol-1 = 2 . 20 x 10-3 molГ°Mole of methyl 3-nitrobenzoate = installment payments on your 20 x 10-3 molMass of methyl 3-nitrobenzoate = (2. 20 x 10-3 mol) by (181. 15g mol-1) = 0. 3991gPercent YieldPercent yield = totally (actual mass/theoretical mass) sama dengan 100% (0. 28436g/0. 3991g)= 71. 2%Part IITheoretical Mass1 mole of just one, 4-Dimethoxybenzene produced 1 skin mole of 1, 4-Di-t-butyl-2, 5-dimethoxybenzene: Gopher of 1, 4-Dimethoxybenzene = zero. 1220g/138. 16 g mol-1...

References: )Williamson, Macroscale and Microscale Organic Experiments, fourth Edition, the year 2003, Chapter twenty-eight & 29, P. 367 - 3852)Solomons and Fryhle, Organic Biochemistry and biology, 8th edition, 2004, L. 669 -- 680

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