Note: Descriptions are shown in the official language in which they were submitted.
De Simone Case 5
10~0550
The present invention relates to the addition of stable
odoriferous components ~odorants) to chlorofluorocarbons, used
as heat transfer media in refrigerant systems, to serve as a de
tection system to warn of loss of refrigerant to the environment.
Such a warning system has become highly desirable in limiting
chlorofluorocarbon 1088 to the atmosphere, in light of the detri-
mental effect these materials are alleged to have on the earth's
ozone layer. Additionally, in absence of a warning system, such
leaks frequently go undetected for quite ~ome time, resulting in
economic 1088 through substantial losses of coolant and reduced
efficiency of the refrigeration system.
There are a number of criteria which an odorant detec-
tion system must fulfill in order to be of use in the typical
chlorofluorocarbon refrigerant systems. It has been found that
traditionally compounded fragrance compositions cau~e problems
in at least one, and more often in several trouble areas. For
example, the compressors used in chlorofluorocarbon refrigerant
systems, eapecially those employed in large capacity industrial
cooling systems, can develop internal temperatures in the chloro-
fluorocarbon medium during the compression cycle of as high as350 to 400F. This temperature is usually highest at the expan-
sion device or di~charge orifice and at this point, most heat
sensitive odorant materials are likely to cause problems by resini-
fying or carbonizing, thus causinq fouling or blocking of the
orifice.
In addition to stability requirements for avoidance of
fouling as just mentioned, there are other criteria which an
odorant must fulfill. It must not roact with the chlorofluoro-
carbon in the presence of other #ystem components, such as the
various metals of construction, drying agent~, lubricating oils
and electrical insulation, which are normally found in refrigera-
tion systems. Al~o, th- odorant mu~t not degrade in the presence
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of trace contaminants in the system, such as air, moisture, or
acidulants. It has been found that certain frequently used
fragrance co~ponents can cause greater than normal corrosion of
the metal components used in chlorofluorocarbon refrigeration
systems, such as steel, aluminum, and copper. One common phenomenon
encountered in refrigerant systems is "copper plating" of the
steel components caused by deposition from ~he copper metal parts
of the system and it is imperative that the odoriferous additives
do not accelerate this process beyond its normal rate. Refrigera-
tion systems have integral dryer material cartridges containing awater trapping agent such as alumina, silica or molecular sieves
to remove traces of moisture which would otherwise cause corrosion
of the metal materials of construction. The odorant material must
not irreversibly absorb onto the drying agents so as to clog them
or otherwise interact and alter their efficiency.
The lubricating oil to refrigerant chlorofluorocarbon
ratios can vary from one to four for household refrigerant
systems to one to one hundred, and preferably one to thirty-five,
for large industrial cooling syste~s. Insolubility can result in
oiling out or precipitation of the odorant and can cause clogging
at the orifice, dryer cartridge, or the moving parts of the com-
pressor, or it can cause a change in the viscosity or lubricity
of the lubricant oil. Also, if the odorant is not fully miscible
with either the oil or the chlorofluorocarbon, it can pool out
and not distribute evenly throughout the system, in which case,
it will not be available at the leak site. It mu~t not, however,
diJso~Ye or cause blistering or ~oftening of in~ulation on the
internal electrical components of the refrigeration systems.
Additionally, the odorant's toxicity to humans must be
low at the intended effective use level and it should dissipate
readily after the leak i8 stopped 80 as not to give a false alarm
after the leak is repaired.
~090ss0
It is the object of this invention to provide certain
classes of compounds which, when added to a fluorocarbon re-
frigerant system, will serve as leak detectors without contrib-
uting to any of the problems set forth hereinabove.
Thus, in accordance with the concept of this invention,
there is set forth hereinafter a series of groups of compounds
which have been found to have utility as leak detection warning
materials which are stable in fluorocarbon refrigerants under
conditions of use of such systems:
I. Aliphatic and cycloaliphatic ethers
II. Aromatic ethers
III. Aliphatic and cycloaliphatic alcohols
IV. Aromatic alcohols
V. Alkyl sulfides
VI. Aliphatic and aromatic nitriles
YII. Terpene hydrocarbons
VIII. Benzenoid hydrocarbons
IX. Aliphatic, cycloaliphatic and aromatic ketones
X. Esters
XI. Phenols
XII. Lactones
XIII. Alpha-diketones
The amount of the odorant compound used is subject to
wLde variation. Generally speaking, the amount will be between
about 0.01 and 5%, preferably about 0.01 and 1%, ba~ed on the
total weight of lubricant and refrigerant. The precise amount
to be employed will depend to a considerable degree upon the odor
int nsity of the particular odorant employed. The amount will
al80 be limited, in some instance~, by the solubility of the
odorant in the lubricant refrigerant mixture.
Within the classes listed above, specific exemplary
compounds are li~ted in the following tabulation:
10~0550
I. Aliphatic and cycloaliphatic ethers
(a) the cineoles
(b) isoamyl heptyl ether
(cl. citronellal dimethyl acetal
tdl geranyl methyl ether
(e) alpha-cedrene epoxide
lfl cedrol methyl ether
II. Aromatic ethers
(a~ diphenyl oxide
(b~ dihydroanethole
lc~ l-phenyl-21(1'-ethoxy)ethoxylethane
~d~ isobutyl benzyl ether
Ce) propyl phenyl ethyl ether
Cf~ methyl chaYicol
(g) para-cresyl benzyl ether
ohl 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexa~ethyl-
cyclopenta-gamma-2-benzopyran
III. ~ hatic and cYcloaliphatic alcohol
(al diisobutyl carbinol
:~ 20 (b) dihydro-alpha-terpineol
(c) linalool
; (d) tetrahydrolinalool
(e) n-hexanol
lf) cis-3-hexenol-1
(g) fenchol
(h) 3,7-dimethyl-octanol-1
(il alpha-terpineol
borneol
IV. Aromatic alcohols
_
(al phenyl dimethyl carbinol
(b) benzyl alcohol
(c~ phenyl ethyl alcohol
5_
1090550
(d) cinnamyl alcohol
(e) para-hydroxymethyl cumene
V. Alkyl sulfides
(a) dimethyl sulfide
(bl dipropyl sulfide
VI. Aliphatic and aromatic nitriles
~a) dimethyl cyclohexene nitriles
(b) 2,3-dLmethyl-2-nonene nitrile
(cl decane nitrile
(d~ geranylonitrile
~el 2,4,5-trimethyl benzonitrile
(f) 4-phenyl butyronitrile
(gl 3-phenyl propionitrile
ohl p-methoxy benzonitrile
YII. Ter~ene hydrocarbon~
(a) alpha-pinene
(bl dipentene
(cl beta-caryophyllene
~dl longifolene
(e) cedrene
~fl camphene
~g) ~\3-carene
YIII. Benzenoid hxdrocarbons
~al p-cymene
(b) l-methyl naphthalene
(cl 2-methyl naphthalene
ld) cumene
IX. Xetones
.
(a) 2-octanone
~1 amyl phenyl ketone
(c) dlphenyl ketone
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(d) benzyl acetone
(e) menthone
~f2 carvone
; (g) para-tertiary butyl cyclohexanone
(h~ methyl heptenone
X. Esters
~a) diethyl phthalate
(b) hexyl hexanoate
(c) methyl-2-octynoate
(d2 benzyl propionate
(e~ isobornyl acetate
~f) para-tertiary butyl cyclohexyl acetate
XI. Phenol~
~a2 thymol
(b) quaiacol
~c2 eugenol
~dl para-ethyl phenol
~e) methyl salicylate
~f) chavicol
(g) creosol
XII. Lactones
:
(a) 3-n-butylidene phthalide
(b) 3-n-butyl phthalide
I (c) 15-hydroxypentadecanoic acid lactone
j ~d) delta-decalactone
¦ (e) gamma-hexalactone
¦ XIII. Diketones
I (a) S-ethyl-3-bydroxy-4-methyl-2 (SH-furanone)
(b) 3-methyl-1,2-cyclohexane dione -
(c) 3-ethyl cyclopentanedione
- . 10905SO
In order to Yerify that odorous materials survive the
heating cycle within refrigeration units, the following test is
employed. The odorant is combined with chlorofluorocarbon s d
lubricating oil and sealed in a glass ampoule with planchets of
copper, steel and aluminum. After a suitable heating period, the
tubes are observed visually for darkening of oil and plating of
copper on the steel planchet. Darkening of the oil indicates a
decomposition of the odorant or of the refrigerant lubricant mix-
ture by the action of the odorant. Plating of copper on the
planchet indicates corrosion of the copper elements within the
system. The planchets are evaluated by comparison with a control
planchet heated in a mixture of lubricant and refrigerant con-
taining no odorant.
B Example 1
Sealed Pyrex glass tubes were prepared containing 2 ml.
of dichlorodifluoromethane (Freon 12, E. I. du Pont de Nemours
Register), 2 cc. of mixed alkyl benzenes lubricant (Suniso 3 GS
oil, Sun Oil Company Register), and 0.01% odorant. Strips of
steel, copper and aluminum were placed in the above-described
fluid mixture and tubes sealed prior to heating at 350F. for
192 hours. Duplicate tubes were prepared for each odorant and
visual results after 24, 96, and 192 hours ~ere recorded (see
Table I). In this series, the aluminum strips remained unchanged,
the copper was bright initially, but had a dull appearance when
first observed after 24 hours at 350F., and did not change sub-
- stantially after. Copper plate formed on the steel strip to an
increasing extent with exposure. In some cases, corrosion appeared
as well. Observations on copper plating are recorded in the column
headed ~stoel~. The colors of the liquids passed through their
initial stage of clear water-white to pale yellow, yellow amber,
broffn and black, but at different rates for the variow samples.
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10gO550
The materials shown in Table I were the odorant products which
were observed to be compatible ~nder the test conditions and which
did not give decomposition of the oil or plating beyond that
observed for the control. All products were run in duplicate te~ts,
which gave identical results in all cases shown.
' 1~90550
~ + m m + m m m + +
~a
.,~
+++ ++++++
~1
m m m m m m m m m
.~ ~
~ P. z ~ ~
m c~ ~ ~ ~o .o
E~
¦ m m m m m m m m m
~ o ~n
E~
!~ u P. ~ ~ m m
3 llllll
- o ~l ~ ~ ~
O
o
I, 8 ,, , 8
--10--
~ `~
l~gOSSO
~ ¦ m m m m m m m + m m
sl
~ ~5
a~ ~1
_, ~ ++++++++++
a~ m m m m m m m ~ m m
. U~
.
O
3 3~ ~
~ 01 m m m m m m m m m m
i~
~ ~ .
~ .
3 z o
~1 ~ .C ~ ~
~ 3 ~ e ~ a ~ i ~
--11--
lW0550
Example 2
SEALED TUBE STABILITY OF ODORANTS
Tests were conducted under the same conditions as in
Example I, except that the weight of odorant was 1% by weight
B in the Suniso 3 GS oil and the duration only 24 hours at
350F. Using the same code as in Example I, the results are
displayed in Table II:
Observation
Compound Liquid Steel
Control #1 2+ C+
Control ~2 1 C
Mixed 1,4- and 1,8-Cineoles 1 C
2,4- and 3,5-Dimethyl-3- 2 C+
Cyclohexene Nitriles
Dimethyl Sulfide 2 C+
1,8-Cineole 1 C
Diisobutyl Carbinol 1 C
Menthone 1 C
Dihydro-alpha-Terpineol 1 C
Tetrahydrolinalool 1 C
Diphenyl Oxide . 1 C
Dihydro Anethole 1 C
`2,3-Dimethyl-2-Nonene Nitrile 2+ C+
n-Hexyl Alcohol 1 C
Phenyl Dimethyl Carbinol 1 C
Alpha-Pinene 1 C
: Decane Nitrile 1 C
2-Octanone 1 C
Para-Cymene 1 C
Fenchol 1 C
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Example 3
An odorant composition to be used as a chlorofluoro-
carbon leak indicator was made up as follows:
Compound Weight in Grams
3,7-Dimethyl-l-Octanol 200
Diphenyl Oxide 9
Dimethyl Sulfide
Mixed 1,4- and 1,8-Cineoles 380
2,4- and 3,5-Dimethyl-3- Cyclohexene 50
Nitrile
1,8-Cineole 100
Menthone . 50
Tetrahydrolinalool 200
¦ Hexanol 10
Total 1000
The above odorant composition wa~ incorporated at 2~ into a
9~ ~xt~e ~ uorotr~ch~oromethane and di~lorodlf~uoro-
methane, respecti~ely, enclo~ed in an aerosol can witb spray
nozzle. Release of 1.0 g. of the aerosol mixt~re into a
well-ventilated room, SO feet by 25 feet, with 12-foo~ ceil-
ing, was readily detectable within 20 feet of the spray's
origin for over 2 minutes.
Example 4
An odorant composition was formulated as described
below:
Compound Weiqht in Grams
Diphenyl Oxide 10
Mixed 1,4- and 1,8-Cineoles 100
Diisobutyl Carbinol 30
~90sso
Compound Wei~ht in Grams
Dihydro-alpha-Terpineol 250
Dihydro Anethole 50
n-Hexanol 10
Phenyl Dimethyl Carbinol 50
Alpha-Pinene 300
2-Octanone 200
Total 1000
The above composition was incorporated into a chlorofluoro-
carbon aerosol spray at 0.2% concentration, as in Example 3,and tested in a similar manner. Release of 1.7 g. of the
odorant and chlorofluorocarbon mixture into a 50-foot by
25-foot room, as described in Example 3, was readily detected
over a span of several minutes within 20 feet of where the
odorant was sprayed.
Example 5
A solution of 10 g. of 2% dimethyl sulfide in
fluorotrichloromethane was charged into an aerosol can and
90 g. of dichlorodifluoromethane charged with pressure. When
0.2 g. of the can contents were released to the atmosphere in
a room as described in Example 3, the odorant was detectable
within 10 to 20 feet of the release site for 1 or 2 minutes
and d~ssipated rapidly theresfter.
.
1~190550
Example 6
Additional testing of odorants was conducted as in
Example 2 with results shown in the table below. Phenols,
acetals, lactones, ester~ of aliphatic and aromatic carboxylic
acids and alkynes were found stable under accelerated tests con-
ducted in the simulated refrigeration system.
TABLE III
0 - better than control
1 - slightly better than control
2 - same as control
3 - worse than control - unacceptable
Result
Compound 96 hrs. 288 hrs. Remarks
N-methyl-2-pyrrolidinone 3 3
Dipropyl disulfide 3 3
Difuryl disulfide 3 3
Thiophenol 3 3
2-Octanone 2 2
Odorant Composition A* 2 2
1-Phenyl-2-1~1'-ethoxy~ 2 2
ethoxy]ethane
CVerotyl, PFW register)
Anethole 2 2
Alpha-terpineol 2 2
Thioacetone 2 3 Attacks aluminum
2,6-Dinitro-3-methoxy-1- 2 3 Coking
methyl-4-tertiary
butyl benzone
S-Ethyl-3-hydroxy-~- 2 2
methyl-2(5H-)furanone
Diethyl phthalate 2 2
Propionic acid 2 2
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10905SO
Re~ult
Compound 96 hrs.- 288 hrs. Remarks
Cis-3-hexenOl-1 2
Heptaldehyde 2 3
Odorant Composition B** 1 2
Thymol
Dipentene
Cyclohexyl mercaptan 1 3Turns copper blue-
gray
10 Hexyl hexanoate 1 0
Methyl-2-octynoate
~eta-caryophyllene 1 2
Butyric acid 0 3Attacks aluminum
*Odorant Compo~ition A
Component Partq by Weight
3,7-Dimethyl octanol 100.0
Dimethyl sulfide 0.5
Diphenyl oxide 9 5
~ixed 1,4- and 1,8-cineoles 240.0
2,~- and 3,5-Cyclohox-3-en nitriles25.0
Eucalyptol 50.0
Diisobutyl carbinol 15.0
Menthone 25.0
Dihydro-alpha-terpineol 125.0
Tetrahydrolinalool 100.0
Dihydroanotholo 25.0
~exanol 10.0
Phenyldimethyl carbinol 25.0
Alpha-pinone 150.0
2-Octanone 100.0
Total 1000.0
~*Odorant Composition B
; Com~onent Parts by Woight
Dimethyl sulfide 60.0
Menthone 50.0
Diphenyl oxide 150.0
Tetrahydrolinalool 100.0
Tetrahydrogeraniol 500.0
Methyl ~al~cylate 100.0
Roso oxide 10.0
Dihydroanothole 30.0
~otal 1000.0
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