PERTEMUAN_15. Predict Rendement of Product a Reaction

RENDEMENT CHEMISTRY

In chemistry, the chemical yield, the yield of the reaction, or only the rendement refers to the amount of reaction product produced in the chemical reaction. [1] Absolute rendement can be written as weight in grams or in moles (molar yield). The relative yield used as a calculation of the effectiveness of the procedure is calculated by dividing the amount of product obtained in moles by the theoretical yield in moles:  

The relative yield used as a calculation of the effectiveness of the procedure is calculated by dividing the amount of product obtained in moles by the theoretical yield in moles:

Rendemen fractional = rendemen actual / theoretical rendemen 

To obtain a percentage yield, multiply the fractional yield by 100%.

One or more reactants in chemical reactions are often used redundantly. The theoretical rendement is calculated based on the number of moles of the limiting reagent. For this calculation, it is usually assumed that there is only one reaction involved.

The ideal chemical yield value (theoretical rendement) is 100%, a value highly unlikely to be achieved in its practice. Calculate the percentage of rendemen that is by using the following equations percent rendemen = weight yield / weight of yield divided by the sample weight multiplied by 100%.

FACT FROM PREDICTION

Is known :

· Ρ Phenol = 1.07 gram / mL BM phenol = 94, 11 gram / mol

· Ρ Formaldehyde 37% = 1.08 gr / mL BM formaldehyde = 30.03 grams / mol

Asked:

Ø Phenol mass = V. Phenol x ρ Phenol

                        = 1mL x 1.07 grams / mL = 1, 07gram

Ø Formaldehyde Mass = V. Formaldehyde x ρ Formaldehyde

                                     = 2 mL x 1, 08 gram / mL = 2.16 grams

So:

Mol Phenol =

                        = = 0.011 mol

TEORY

We can learn with this practice :

Formaldehyde Phenol Polymers

The purpose of this pratikum is:

A. Praktikan know the process of making formaldehyde phenol

B. Praktikan able to conduct experiments of condensation polymerization

C. Praktikan able to recognize the characteristics of condensation polymerization

D. Praktikan able to study the making of phenol formaldehid by using base catalyst.

Polymers are a science that develops applicatively. Paper, plastics, tires, natural fibers, are products of polymer products. Polymers are giant molecules (macromolecules) formed by repeating simple units of monomer.

             Polymers can be grouped by source, ie natural polymers and synthetic polymers. In addition, the polymer may also be grouped from chain arrangement, polymerization reaction, monomer type, thermal properties and application. Synthetic polymers are materials that are widely used in our daily life in various applications. One type of synthetic polymer widely used commercially in both the plastic and paint industries (surface coatings) is phenol formaldehyde.

             Phenol formaldehyde is a thermosetting synthetic resin, produced from the condensation polymerization reaction between phenol and formaldehyde. One application of phenol formaldehyde resin is for varnish.

          Phenol is also known as carbolic acid or benzenol is a colorless crystalline substance that has a distinctive odor. Phenol is an organic compound whose chemical formula is C6H5OH and its structure has a hydroxyl group (-OH) attached to a phenyl ring.

METHODELOGY

1.1 Tools and Materials

A. The tools used in the experiment are:

1. Analytical balance sheet 6. Pipette drops

2. Test tube 7. Bunsen lamp

3. Mixers 8. Tweezers

4. Pipette volume 9. Mold (porcelain cup)

5. Pro pipette

B. The materials used in the experiment are:

Ø Phenol solution

Ø Formaldehyde solution 37%

Ø 2.5 N NaOH solution

Ø Rock didh

Ø Aluminum foil

1.2 Working steps

· Prepared tools and materials to be used.

· Dipipet 1 cc of phenol solution then put in the test tube.

· Added 2mL of 37% formaldehyde solution, then shaken the test tube to homogeneous solution.

· Added 2 drops of 2.5N NaOH solution and inserted sufficient boiling stones into the test tube, then the reaction tube clamped and then heated to a white milk-colored solution

· Stopped warming, allowed to separate mixture into two phases. The top layer is taken with a dropper pipette (the top layer is mostly water, and the bottom layer is yellow thick liquid)

Then the bottom layer is reheated until it becomes brown and then expands and eventually turns into a solid like a reddish-brown glass, after being poured into a mold that has been coated with aluminum foil.

1.3 Anali sis Data

Table 1. Comparison of polymer preparation results from all groups

No

Group

B.Mold print

B. Molds + polymers

Polymer weight

Polymerization Time

1.

I.

129.369 grams

131,282 grams

1.913 grams

2.

II

34,081 grams

35.705 grams

1,624 grams

3.

III

143,811 grams

146,681 grams

2,870 grams

15 minutes

4.

IV

132,553 grams

135.156 grams

2,002 grams

5.

V

125.320 grams

128.210 grams

2,890 grams

3.50 minutes

6.

VI

41, 125 grams

42.752 grams

1,627 grams

9 minutes

7.

VII

134, 709 grams

135,270 grams

0.561 grams

13 Minutes

Type:

Ü Volume of phenol: 1 ml

Ü Formaldehyde volume 37%: 2 ml

Ü V NaOH: 22 drops

Color Changes during Polymerization

1. Phenol + Formaldehyde = brown

2. Phenol + formaldehyde + NaOH 2.5 N = Old Chocolate

3. Phenol + Formaldehyde + NaOH 2.5 N after heated = Young white sediment chocolate and then reheated to remove water reddish-brown solution poured on a mold coated with aluminum foil and let it harden and freeze.

3.4 Calculations

Is known :

· Ρ Phenol = 1.07 gram / mL BM phenol = 94, 11 gram / mol

· Ρ Formaldehyde 37% = 1.08 gr / mL BM formaldehyde = 30.03 grams / mol

Asked:

Ø Phenol mass = V. Phenol x ρ Phenol

                        = 1mL x 1.07 grams / mL = 1, 07gram

Ø Formaldehyde Mass = V. Formaldehyde x ρ Formaldehyde

                                     = 2 mL x 1, 08 gram / mL = 2.16 grams

So:

Mol Phenol =

                        = = 0.011 mol

DISCUSSION

Theoretically, the production of phenol formaldehyde by using a base catalyst with a mole ratio of reactant P / F> 1, the resulting product is a thermoset resol type. Resol is the result of a reaction between phenol and formaldehyde excess by the presence of an alkaline catalyst. The most commonly used types of base catalysts are sodium hydroxide (NaOH) and ammonium hydroxide (NH₄OH) at pH = 8-11. The product of phenol formaldehyde produced with a sodium hydroxide catalyst will have a water solubility and if the catalyst used ammonium hydroxide will give insoluble in water due to the formation of bis and tris hydroxylbenzylamin (Martin, 1956).

CONCLUSION

From the results of the discussion above can be summed up as follows:

  Phenol formaldehyde is a synthetic polymer prepared by the process of condensation with a by-product of water.