Boiling Points & Densities of Aliphatic Alcohol Acetates: A Study by Wojciechowski & Smith | Lecture notes Literature

U.

S.

DEPARTMENT

OF

COMMERCE

NATIONAL

BUREAU

OF

STANDARDS

RESEARCH PAPER RP989

Part

of

Journal

of

Research

of

the National Bureau

of

Standards,

Volume

18,

April

1937

BOILING

POINTS

AND

DENSITIES

OF

ACETATES

OF

NORMAL

ALIPHATIC

ALCOHOLS

By Mieczyslaw Wojciechowski 1 and Edgar

R.

Smith

ABSTRACT

The

boiling

points,

rates

of

change

of

boiling

point

with

pressure,

and

densiti

es

of

methyl

acetate,

ethyl

acetate,

n-propyl

acetate,

and

n-butyl

acet

a

te

were

measured

by

precise

comparative

methods

using

water

as

the

reference

s

tandard

.

As

in

on

the

normal

saturated

hydrocarbons

and

normal

aliphatic

alcohols,

it

was

found

that

the

introduction

of

each

CH

2

group

into

the

chain

of a

molecule

containing

a

normal

alkyl

group

of

more

than

some

small

number

n

of

carbon

atoms

causes

dt/dp

to

increase

by

a

constant

value

which

is

independent

of

the

chemical

nature

of

the

molecule.

CONTENTS

Pag

•

1.

Methods

of measurement___________________________________ ____

499

II.

Method

of

extrapolation

of

the

data_

_ _ _ _ _ _ _ _ _ _ _ _ _ _

__

_ _ _ _ _ _ _ _ _ _ _ _ _

500

III.

Purification

of

materials________________________________________ 501

1.

Methylacetate____________________

______ ______

__

_____

__

501

2.

Ethylacetate

__________ _

___

_

___

__

_______________ _

__

____ 501

3.

n-Propyl

acetate___

_ _ _ _

__

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

__

_

__

_ _

__

_ _ _ _ 501

4.

n-Butyl

acetate_________________________________________ 501

IV.

Experimental

results

and

conclusions____________________________ 501

V. References_____

__

_ _ _ _ _ _ ____ _ _ _ _

__

_ _

__

_

__

_ _ _

__

_ _ _ _

__

_ _ _ _ _ _ _ _ _ _ _

504

1.

METHODS

OF

MEASUREMENT

In

previous papers

it

was shown

that

in

the homologous series of

normal

saturated

hydrocarbons

[11]

2 and normal aliphatic alcohols

[12],

containing more

than

some small number n of carbon atoms,

the

addition

of

a

CH

2 group to

the

normal alkyl group to form

the

per

millimeter of mercury

in

the

coefficient dt/dp

at

the normal boiling

point. Since this value was found to be independent of

the

chemical

nature

of the compound,

the

additivity of the effect

of

the

CH

2 group

on

dt/dp was postulated.

In

this paper a similar investigation of

the

relation between the dt/dp coefficient and

the

molecular weig

ht

of

the

compound

in

the series of acetates of normal aliphatic alcohols

is

described.

In

addition, there are reported the boiling points

and

densities of

the

following esters: methyl acetate, ethyl acetate,

n-

Qropyl aceta.te, and

n-butyl

acetate.

For

determining boiling points

Swi~toslawski's

ebulliometric technic

[7]

and comparative method

with water as a

primary

standard

was applied. Details

of

th e experi-

mental procedure for determining the boiling point and

the

coefficient

I Guest Worker

from

the Polytechnic Institute,

War

sa

w,

Poland.

I

The

fi

gures in brackets refer to reference,

li

sted

at

tbe end

of

the paper.

126219-37--8

499

Boiling Points & Densities of Aliphatic Alcohol Acetates: A Study by Wojciechowski & Smith, Lecture notes of Literature

Related documents

Partial preview of the text

Download Boiling Points & Densities of Aliphatic Alcohol Acetates: A Study by Wojciechowski & Smith and more Lecture notes Literature in PDF only on Docsity!

U. S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS

RESEARCH PAPER RP

BOILING POINTS AND DENSITIES OF ACETATES OF

NORMAL ALIPHATIC ALCOHOLS

By Mieczyslaw Wojciechowski 1 and Edgar R. Smith

millimeter of mercury in the coefficient dt/dp at the normal boiling

on dt/dp was postulated. In this paper a similar investigation of the

relation between the dt/dp coefficient and the molecular weight of the

50 0 Journal oj Research oj the National Bureau oj Standards [Vol. 18

dt/dp have been described briefly in the paper on hydrocarbons [11].

where t. represents the normal boiling point of the substance under

investigation, t'. the boiling point actually measured, and t' '" the

II. METHOD OF EXTRAPOLATION OF THE DATA

Table 2 contains the values of dt,/dt w, the ratio of chan~e of boiling

point of each substance to the change of the boiling pomt of water

caused by a smaH increment of pressure, and values of dt/dp, the

increment of boiling point per millimeter of change of pressure. The

values in parentheses were obtained by interpolation.

Substance IU. pointwater 01 (~) .-110 Difference

The data for dt,/dt w permit one to calculate the correction for normal

boiling points of the substances, within the pressures expressed by

the reported boiling points of water. They may serve also to com-

pute the value of dt/dp corresponding to any pressure within the

reported limits, by the use of the equation

3(dt) dt, (dt)

dp ,=dt w• dp fJI

Data for the densities of the esters investigated are given in table 3.

.89471}^.^89468 .8946,

tI-Propyl acetate__________________________________ ----j .00^4 .88297^ .88297^ } .8830,

.011 { PI 2. ·88286 88286 }.

Table 4 contains a comparison of the authors' data with some

previously reported.

I

From table 2 it is obvious that in the case of acetates the introduc-

tion of each CH 2 group into the chain of a molecule causes an increase

of the dtjdp coefficient by a substantially constant value, the average

for the esters investigated being equal to 0.0028. This increment

agrees with that measured for a series of normal saturated hydrocar-

bons [111 and normal aliphatic alcohols [121.

The authors wish to tender their thanks to H. Matheson for assist-

ance in the purification of some of the substances.

One of us 4 wishes to express his gratitude to the Polish Fundusz

Kultury Narodowej in Warsaw (Polish Fund of National Culture)

for financial aid.