Trioctylammonium molybdates having the empirical formula EQU [(C.sub.8 H.sub.17).sub.3 NH].sub.a Mo.sub.b O.sub.c where a, b and c are (2, 6, 19); (6, 7, 24) or (4, 8, 26) are disclosed as novel amine molybdates which are useful as smoke retardant additives for vinyl chloride polymer compositions.

BACKGROUND OF THE INVENTION 
Amine molybdates may be produced by reacting an amine or an amine salt with 
a molybdenum compound such as molybdenum trioxide (MoO.sub.3), molybdic 
acid or a molybdenum salt in an acidic aqueous medium made acidic through 
the addition of a suitable acid such as an inorganic acid (exemplified by 
hydrochloric acid, nitric acid or sulfuric acid) or an organic acid 
containing 1 to 12 carbon atoms (exemplified by acetic acid, propionic 
acid, benzoic acid, and the like). The acidic mixture is refluxed, 
preferably while being stirred continuously, until the reaction is 
complete, usually for about 1/4 to 4 hours. 
Amine molybdates also may be produced, as described in U.S. Pat. No. 
4,217,292, by reacting essentially stoichiometric quantities of molybdenum 
trioxide with an amine or an amine salt in an aqueous medium essentially 
free of acid and in which a water-soluble ammonium or monovalent metal or 
divalent metal or trivalent rare earth metal salt of an inorganic or 
organic acid is dissolved. Sometimes the reaction is carried out in a 
polar organic solvent instead of water. 
The particular amine molybdate formed may depend upon which process is used 
to form the amine molybdate and the quantity of reactants present in the 
reaction mixture, as well as the reaction conditions. 
SUMMARY OF THE INVENTION 
The present invention pertains to a class of novel molybdates, namely, 
trioctylammonium molybdates, which may be represented by the formula: 
EQU [(C.sub.8 H.sub.17).sub.3 NH].sub.a Mo.sub.b O.sub.c 
where a, b and c are (2, 6, 19) (6, 7, 24) or (4, 8, 26). Like many other 
amine molybdates, the trioctylammonium molybdates function as effective 
smoke retardant additives for vinyl chloride polymers. 
DETAILED DESCRIPTION OF THE INVENTION 
Trioctylammonium molybdates may be produced by reacting ammonium 
dimolybdate [(NH.sub.4).sub.2 Mo.sub.2 O.sub.7 ] and trioctylamine 
[(C.sub.8 H.sub.17).sub.3 N] in an acidic aqueous medium. Suitable acids 
include inorganic acids such as hydrochloric acid, nitric acid, or 
sulfuric acid, or mixtures thereof. The amount of acid used may be varied 
widely from about 1/2 to 10 or more molar equivalents of acid per molar 
equivalent of ammonium dimolybdate. However, about a 1/1 molar equivalent 
ratio is preferred. Sufficient water is included in the reaction mixture 
to insure a reaction mixture that has a consistency that enables it to be 
easily stirred. The mixture is heated to reflux and refluxed for about 10 
minutes to 16 hours, preferably while being stirred continuously. After 
the reaction is completed, the solid reaction product is separated from 
the aqueous medium by filtration, centrifugation, or other suitable 
separation procedure. The recovered solid reaction product desirably is 
washed with water and then is dried. The molar ratio of ammonium 
dimolybdate to trioctylamine will influence the trioctylammonium molybdate 
product formed as a result of the reaction. Theoretical 
molybdate/trioctylamine molar ratios from 0.5/1 to 3/1 are used. However, 
the actual molar ratios that can be used in the reaction can be outside 
the stated range. 
Not all of the realizable trioctylammonium molybdates can be prepared as 
described above. Certain of them can be best prepared by reacting 
previously formed trioctylammonium molybdates with a strong inorganic 
acid, such as hydrochloric acid, in polar solvents such as water, 
methanol, and acetonitrile. 
The trioctylammonium molybdates within the scope of the present invention 
are trioctylammonium hexamolybdates [(C.sub.8 H.sub.17).sub.3 NH].sub.2 
Mo.sub.6 O.sub.19, trioctylammonium heptamolybdates [(C.sub.8 
H.sub.17).sub.3 NH].sub.6 Mo.sub.7 O.sub.24 and trioctylammonium 
octamolybdates [(C.sub.8 H.sub.17).sub.3 NH].sub.4 Mo.sub.8 O.sub.26.

The following examples more fully illustrate the preparation of the novel 
trioctylammonium molybdates of the present invention. 
EXAMPLE I 
10.00 Grams of trioctylamine were added to a 500 milliliter round-bottom 
flask equipped with a water-cooled condenser and a mechanical stirrer. 
5.58 grams of a 37 percent hydrochloric acid solution were mixed with 200 
milliliters of water and were added to the flask. 9.62 grams of ammonium 
dimolybdate were dissolved in 50 milliliters of water and added to the 
flask. The mixture in the flask was heated to reflux and refluxed for 10 
minutes and then was cooled to room temperature (about 25.degree. C.). The 
cooled mixture was poured into a Buchner funnel. A yellowish-green residue 
was collected on the filter paper. The residue was washed three times with 
about 50 milliliters of water and dried in a vacuum oven maintained at 
about 65.degree. C. for 11/2 hours. Infrared analysis identified the 
residue to be a mixture of trioctylammonium alpha- and beta- 
octamolybdates. 
3.12 Grams of trioctylammonium octamolybdate and 20 milliliters of 
acetonitrile were added to a 50 milliliter Erlenmeyer flask and stirred 
until the trioctylammonium octamolybdate was dispersed within the 
acetonitrile. 0.08 gram of concentrated sulfuric acid was mixed with 3 
milliliters of water and added to the flask. The contents of the flask 
were warmed and stirred for 2 hours. The solid molybdate charged to the 
flask was converted to a light brown oily product. The contents of the 
flask were cooled to room temperature (about 25.degree. C.). The 
acetonitrile/water layer was separated from the light brown oily layer. 
The oily product was washed three times with separate water washes of 20 
milliliters of water, the oily layer being separated from the water wash 
after each wash. The oily product was dried in a vacuum oven at 40.degree. 
C. for 16 hours. The dried oily product was dissolved in 20 milliliters of 
acetonitrile. 0.04 Gram of concentrated sulfuric acid was added to the 
solution and the resulting mixture was stirred for 1/2 hours. The mixture 
was rotoevaporated to dryness. A green oily product was obtained. The oily 
product was dried in a vacuum oven at 40.degree. C. for 2 hours. Infrared 
analysis identified the product as trioctylammonium hexamolybdate 
containing a small amount of unreacted trioctylammonium octamolybdate. 
EXAMPLE II 
The trioctylammonium molybdates have been found to be a smoke retardant 
additive for vinyl chloride polymer compositions. When used as a smoke 
retardant additive, the trioctylammonium molybdates desirably either are 
combined with the other ingredients of the vinyl chloride polymer 
composition on a roll mill or added by any other convenient mixing 
procedure. Preferably, from about 0.1 to about 20 parts by weight of a 
trioctylammonium molybdate is used per 100 parts by weight of vinyl 
chloride polymer. 
Vinyl chloride polymers with which the trioctylammonium molybdates can be 
used as smoke retardant additives include homopolymers, copolymers and 
blends of homopolymers and/or copolymers, and include chlorinated polymers 
thereof. The vinyl chloride polymers may contain from 0 to 50 percent by 
weight of at least one other olefinically unsaturated monomer. Suitable 
monomers include 1-olefins containing from 2 to 12 carbon atoms such as 
ethylene, propylene, 1-butene, isobutylene, 1-hexene, 4-methyl-1-pentene, 
and the like; dienes containing from 4 to 10 carbon atoms, including 
conjugated dienes such as butadiene, isoprene, piperylene, and the like; 
ethylidene norbornene and dicyclopentadiene; vinyl esters and allyl esters 
such as vinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl 
laurate, alkyl acetate, and the like; vinyl aromatics such as styrene, 
.alpha.-methyl styrene, chlorostyrene, vinyl toluene, vinyl naphthalene, 
and the like; vinyl allyl ethers and ketones such as vinyl methyl ether, 
allyl methyl ether, vinyl isobutyl ether, vinyl n-butyl ether, vinyl 
chloroethyl ether, methylvinyl ketone, and the like; vinyl nitriles such 
as acrylonitrile, methacrylonitrile, and the like; cyanoalkyl acrylates 
such as .alpha.-cyanomethyl acrylate, the .alpha.-.beta.- and 
.alpha.-cyanopropyl acrylate, and the like; olefinically unsaturated acids 
and esters thereof including .alpha.,.beta.-olefinically unsaturated acids 
and esters thereof such as methyl acrylate, ethyl acrylate, chloropropyl 
acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, dodecyl 
acrylate, octadecylacrylate, methoxyethyl acrylate, ethoxyethyl acrylate, 
hexylthioethyl acrylate, methyl methcarylate, ethyl methacrylate, butyl 
methacrylate, and the like. 
The vinyl chloride polymer, in addition to the trioctylammonium molybdate, 
may contain the usual compounding ingredients known to the art such as 
fillers, stabilizers, opacifiers, lubricants, processing aids, impact 
modifiers, plasticizers, antioxidants, and the like. 
Smoke retardancy may be measured using an NBS Smoke Chamber according to 
procedures described in ASTM E662-79 "Test For Specific Optical Density Of 
Smoke Generated By Solid Materials". Maximum smoke density (Dm) is a 
dimensionless number and has the advantage of representing a smoke density 
independent of chamber volume, specimen size or photometer path length, 
provided a consistent dimensional system is used. Percent smoke reduction 
is calculated using the equation: 
##EQU1## 
The term "Dm/g" means maximum smoke density per gram of material. Dm and 
other aspects of the physical optics of light transmission through smoke 
are discussed fully in the ASTM publication. 
Smoke retardance may be measured quickly using the Goodrich Smoke-Char 
Test. Test samples may be prepared by dry blending polymer resin and smoke 
retardant additives. The blend is ground in a liquid nitrogen cooled 
grinder to assure uniform dispersion of the smoke retardant additives in 
the resin. Small (about 0.3 g) samples of the polymer blend are pressed 
into pellets about 1/4 inch diameter for testing. Alternatively, test 
samples may be prepared by blending resin, smoke retardant additives and 
lubricant(s) or processing aid(s) in a blender such as an Osterizer 
blender. The blend is milled, pressed into sheets, and cut into small 
(about 0.3 gram ) samples for testing. The test samples are placed on a 
screen and burned for 60 seconds with a propane gas flame rising 
vertically from beneath the samples. Sample geometry at a constant weight 
has been found not to be significant for the small samples used in this 
test. A Bernz-O-Matic pencil flame burner head is used with gas pressure 
maintained at about 40 psig. Each sample is immersed totally and 
continuously in the flame. Smoke from the burning sample rises in a 
vertical chimney and passes through the light beam of a Model 407 
Precision Wideband Photometer (Grace Electronics, Inc., Cleveland, Ohio) 
coupled with a photometer integrator. Smoke generation is measured as 
integrated area per gram of sample. 
The smoke retardant property of trioctylammonium molybdates is illustrated 
by the following example: 
EXAMPLE III 
The following recipe was used: 
______________________________________ 
Material Parts by Weight 
______________________________________ 
Polyvinyl Chloride resin* 
100.0 
Lubricant** 2.0 
Tin Stabilizer*** 2.0 
Trioctylammonium molybdate 
5.0 
______________________________________ 
*Homopolymer of vinyl chloride having an inherent viscosity of about 
0.98-1.04; ASTM classification GQ5-15543. 
**A commercial polyethylene powder lubricant (Microthene 510). 
***Tin Thioglycolate 
5.0 Grams of the trioctylammonium gamma-octamolybdate of Example I were 
mixed with 100.0 grams of the polyvinyl chloride resin of the aforesaid 
recipe on a two-roll mill. The lubricant and tin stabilizer of the recipe 
were added to the molybdate-polyvinyl chloride resin mixture and the 
resulting composition was milled on the mill for about 5 minutes at a roll 
temperature of about 165.degree. C. The milled composition was pressed 
into a 6.times.6.times.0.050 inch sheet. Pressing was done at about 
160.degree. C. for 5 minutes using 40,000 pounds (about 14,900 kg) of 
force applied to a 4-inch ram. The sample (Sample 1) received a 2 minute 
preheat before being pressed. 
The molded samples were cut into 2 7/8.times.2 7/8.times.0.50 inch 
sections and tested against a control sample formed utilizing the 
aforesaid recipe but without use of the molybdate additive. Testing was 
performed using the flaming mode of the NBS Smoke Chamber Test (ASTM 
E662-79) described hereinabove. The test results are given in Table I. 
TABLE I 
______________________________________ 
Sample Dm/g* Smoke Reduction (%) 
______________________________________ 
Control 60.8 -- 
1 28.4 53.3 
______________________________________ 
*Dm/g maximum smoke density per gram of sample. 
0.075 Gram of the slightly impure trioctylammonium hexamolybdate product of 
Example II and 1.50 grams of polyvinyl chloride resin (homopolymer of 
vinyl chloride having an inherent viscosity of about 0.98-1.04, ASTM 
classification GO-5-15543) were blended together in a nitrogen-cooled 
grinder. The mixture (Sample 2) was cold-pressed into 1/4 inch diameter 
pellets weighing about 0.3 gram each. 
A "control" sample was prepared by forming pellets of the polyvinyl 
chloride resin. 
Testing was preformed using the Goodrich Smoke-Char Test described above. 
The test results are set forth in Table II. 
TABLE II 
______________________________________ 
Sample Spvc* Smoke Reduction (%) 
______________________________________ 
Control 74.8 -- 
2 39.5 47.2 
______________________________________ 
*Smoke-Char test smoke number 
The improved smoke retardant vinyl chloride polymer compositions obtained 
by the inclusion of a trioctylammonium molybdate in the composition are 
useful wherever smoke reduction is a desirable property, such as in 
carpeting, house siding, plastic components for aircraft and passenger car 
interiors, and the like.