Note: Descriptions are shown in the official language in which they were submitted.
~L~6~659
The pxesent invention relates to a process for protecting `~
wood against fungi and insects with a wood preservative containing
o-boric acid/prop~lene oxide adduct.
i,
~ t is known (Chemical Week, 3uly 26, 1972, p. 43) to use
boric acid for protecting wood against insects and fungi.
We have now found that o-boric acid/propylene oxide
adducts have a strongly destructive actîon on wood-destroying
insects and fungi, and are therefore eminently suitable as wood
preservatives. By "wood" is meant not only solid wood but also `
wood-base materials prepared from wood particles, e.g., wood chips. ;~
The adducts exhibit not only a good fungicidal action but
also an action on ligniperdous insects such as Hylotrupes bajalus, `~
,~
Anobium punctatum and Lyctus ~runneus, and on termites. The following .
ligniperdous fungi and soft rot and mold fungl may be controlled
with the active ingredients of the invention:
,;
Coniophora cerebellaj Merulius lacrimans, Lentinus lepideus,
Lenzites trabea, Porio vaporaria, Polystictus (Coriolus) versicolor,
Paxillus panuoides, Stereum purpureum, Fomes annosus, Bispora
effusa, Stachybotrys atra, Chaetomium globosum, Trichoderma viride,
2Q Aspergillus niger, Hormiscium spec., and Stemphylium spec.
By contract to boric acid and borax, which are unsuitable
as active ingredients for oil-type wood preservatives on account
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~V~659
of their poor solubility in or~anic solvents, the o-boric acid/ ~-
p~pylene oxide adducts are very readily soluble in the aromatic
and aliphatic solvents usually employed; these active ingredients _ -
in solvent formulations also mix well with other fungicides and
insecticides used for protecting wood~ Compounds with which the
adducts of the invention are miscible are for example the `
aluminum salt Or N-cyclohexyl-N~nitrosohydroxylamine, pentachloro-
phenol, chloronaphthalene, N-dichlorofluoromethylthio-N',N'-di-
methyl-N-phenylsulfonyl diamide, and N-phenyl-N,N~-dimethyl-N~
10 dichlorofluoromethylthiosulfonyl diamideO The active ingredients
.
may not only be used in solvent wood preservative formulations ~-
which are applied to the wood by painting, dipping or spraying,
but also added, in aqueous solution, to glues for the manufacture
of wood-base materials. Sultable binders for the manufacture of
wood-base materials are urea/formaldehyde, melamine/formaldehyde,
urea/formaldehyde/melamine and isocyanate resins. As the active
ingredient solutions can be added to the glue direct, there is
no danger, as is the case with o-boxic acid, of the formation of
lumps which result in poor distribution of the active ingredient.
It is also known that, when o-boric acid is mixed with wood chips
before gluing, difficulties occur with regard to homogeneous
distribution~ Furthermore, aqueous active ingredient solutions
may also be used for impregnating wood by the pressure process. ~ ~
The wood to be protected against insect and fungus attack ~~ -
is treated with the preservative in such a manner that the active
ingredient is uniformly distributed over the surface of the wood
and penetrates into the wood as far as possible. When the surface
is treated, the applioation rate i8 approximately 5 to 100 g of
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active ingredient per m . For impregnation, or for the
treatment of wood ch~ps in the manufacture of wood-base -'materials, the application rate is about 5 to 25% of
active ingred~ent, ~ased on dry wood substance. Examples
of suitable solvents fcr the active ingredient are benzene -~
fractions conta~ning up to 30wt% of aromatics, drying oils
such as are used in paintaing, alcohols, esters, ketones
and ~lycol ethers. The active ingredient may also be mixed
with solid carriers such as clay, silica gel, lima dust and
lQ diatomaceous earth.
The present invention is concerned with a process `~
for protecting wood against ligniperdous insects, termites,
ligniperdous fungi, soft rot and mold fungi, which comprises ~ -
bringing into contact with the wood an effective amount of -~
wood preservative compounds effective against ligniperdous
insects, termites, ligniperdous fungi, soft rot and mold fungi,
said compounds being o-boric acid/propylene oxide adducts having
a molar ratio of said acid to said propylene oxide in the range '
of 1:1 to 1:5, respectively, said adducts being formed by
2Q reacting said o-bor;c acid and propylene oxide either in an '~
aprotic solvent at 100C to 160C in the absence of a catalyst -'
or at 70C to 120C in a closed vessel in an aprotic solvent -'
and in the presence of a catalytic amount of a base or a Lewis
acid at a pressure of said propylene oxide of 4 to 9 bars,
and thereafter distilling off said solvent.
The wood preservatives contain ~rom about 1 to
30wt% of the o-boric acid/propylene oxide adduct. "
In accordance with the invention, "aprotic organic ;'
solvents" are those which do not possess a mobile hydrogen
3~ atom in the molecule. They may be polar or non-polar. ,~
Examples of polar solvents are acetone, dioxane, dimethyl~
formamide, formamide, and dimethyl acetamide; carbon
tetrachloride is an example of a non-polar solvent.
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The reaction may be carried out preferably at
temperatures of from 12a to 150C without the addition
of catalysts. It is however preferred to carry out the
reaction in the presence of bases or Lewis acids because
these reagents have a catalytic action. Examples of bases
are terkiary amines such as dimethyldodecylamine, catalytic
amounts of an alkali such as sodium hydroxide, and alkoxides
such as sodium methylate and potassium tert-butylate; examples
of Lewis acids are boron trifluoride etherate, aluminum chloride
and zinc chloride. When catalysts are used, the temperatures
employed are preferably from 80 to 110 C.
In th;s case the reaction is expediently carried out
in a closed system, for instance an autoclave, in which is placed
the aprotic solvent a~d to which is added from 20 to 200wt%, based
on solvent, of o-boric acid and, if desired, from 0.1 to 5wt% of
base or Lewis acid, based on o-boric acid.
The system is then pressured, in accordance with the
molar ratios given, with from 1 to 5 times, preferably from 3
to 4 times, the molar amount of propylene oxide, based on o-boric
acid, and the contents heated to from 70 to 120C and as
stated above pre~erably from 80 to 110C. By definition the
pressure should rise preferably to from 5 to 7 bars. The total -~
. . .
duration of the reaction is about 3 to 8, preferably 5 to 6,hours.
Upon completion of the reaction and after the pressure
in the
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reaction vessel has been let down, the solvent and water of
reaction are removed by distillation~ -
Depending on the amount and type Or alkylene oxide used,
there remain water-soluble to water-insoluble, liquid to viscous
products which can be characterized by viscosity, infrared spec-
troscopy~ and mass spectroscopy.
Visco~ity measurements carried out on propoxylation products
give for~instance - at 20C - viscosities of 1,600 to 1,700 cSt;
butoxylation products approx. 100 cSt. -
Inrrared spectra have B-0 bands at 1,310 to 1,350 cm 1.
In mass spectroscopy, characteristic fragments are obtained
from which it is possible to conclude that the reaction products
are, depending on the molar ratios of o-boric acid to propylene
:i
oxide, cyclic esters, the most frequent of which are compounds
having the following structure:
2nCn ~ ~ E-0-CnEl2n-0-E \ / enH2n
0C H2n0\ -.
n = 2 to
0CnH2n0
;c . , , ~
Some Or the products obtained by the process Or the invention
- can be puri~ied by distillation and fractionatedO They may be
used a5 a mixture or as individual fractions.
The following examples, in which the parts are by weight,
illustrate the invention
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O.Z 31,996 ~ -
EXAMPLE 1
o-boric acid/1 2-butylene oxide
In a V2A stirred autoclave are placed 93 parts (1.5 moles) ,`
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of o-boric acid, 93 parts oP dioxane and 2.79 parts ~3wt%, based
on o-boric acid) of dimethyldodecylamine; subsequently, 432 parts r~ .
(6 moles) of 1,2-butylene oxide is pressured in in portions at
130 to 140Co
Pressuring time: 3 hours
Pressure: 7 atmospheres gauge
Temperature: 138C ~ -
Stirring time: 3 hours
A clear brown liquid is obtained. The rate of conversion,
based on oxide consumption, is 1:3.60
After removal of residual epoxide and the mixture of dioxane
and water of reaction, 3 Practions are obtained: j~
Fraction I: b.p. (0.7 mm) 57C, 37 g; n20: 1.4390 -
Fraction II: b.p. (0.5 mm) 120-130C, 75 g; n20: 1.4400-1.4404 ;~
D20: 0.995
Fraction III: b~p. (0.5 mm) 145-160C, 17 g; n20: 1.4411-1.4444
~20 ~ 9~ cP (98.6 cSt)
(290 g of resinous residue)
EXAMPLE 2 ~- `
o-boric acid/ethylene oxide
In a V2A stirred autoclave are placed 248 parts (4 moIes)
of o-boric acid, 248 parts of dioxane and 3.72 parts (1.5wt%,
based on o-boric acid) oP BF3 etherate; subsequently, 528 parts
(12 moles) of ethylene oxide is pressured in in portions at
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O.Z. 31,996
110 to 120C, and unreacted ethylene oxide and the mixture
of dioxane and water of reaction are removed in vacuo at 90 to
100C/15 mm Hgo
There is obtained 775 parts of a pasty wax-like (Vaseline-
like) compound. The rate of conversion, based on oxide consumption,
is 1:3, .
Pressuring time: 6 hours
Pressure: 7 atmospheres gauge ..
Temperature: 110-115C `
Stirring time: 3 hours
EXAMPLE 3
o-boric acid/1,2-butylene oxide :
~ In a V2A stirred autoclave are placed 93 parts (1.5 moles) 1~ -
¦ of o-boric acid, 18~ parts of dioxane and 2.79 parts (3wt%, based ;~
on o-boric acid) of sodium methylate; subsequently, 378 parts
(5.25 moles) of 1,2-butylene oxide is pressured in in portions ~
at 135 to 140C. ;
Pressuring time: 6 hour~
Pressure: 7 atmospheres gauge ,- ; ~ :
: Temperature: 138C .
¦~ Stirring time: 3 hours
11 parts of unreacted o-boric acid is separated by suction ~ .:
filtration from the dioxane solution containing water of reaction. ::
The rate of conversion, based on oxide consumption, is 1:2.5.
l After removal of the dioxane-water mixture, the unreacted ~:
., epoxide and high vacuum distillation, 3 fractions are obtained: :
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OOZ. 31,996
Fraction I: bop~ (Ool mm) 53-55C/23 parts of a pale yellow oil f'
Fraction II: b~p (002 mm) 95C/14 parts of a pale brown oil
Fraction III: b,p~ (003 mm) 160C/ 42 parts of a pale brown oil
90 g of a resinous residue
EXAMPLE 4 -~
o boric acid/propylene oxide
,, .
In a V2A stirred autoclave are placed 248 parts (4 moles) ~`
of o-boric acid, 7.44 parts (3wt%, based on o-boric acid) of
dimethyldodecylamine and 248 parts of dioxane; subsequently, `r
928 parts (16 moles) of propylene oxide is pressured in in '~
portions at from 100 to 110Co
Pre suring time: 8 hours
Pressure: 8 atmospheres gauge f~,' '
Temperature: 108C ;~
Stirring timeo 3 hours -
After removal of the excess propylene oxide and the mixture "f'~ ~ . ' `, '`
of dioxane and water of reaction, 1,013 parts of a pale yellow
oil is obtained.
d20: 1.070-10065 ;`;f'''~''""
n20: 10444 ~ `
~20 1,695 cP
b.p. (760 mm): 270C
Rate o~ conversion, based on oxide consumption: 1:303 ~`
..
EXAMPLE 5
o-boric aic/2,3-butylene oxide
In a V2A stirred autoclave are placed 93 parts (1.5 moles)
of o-boric acid, 93 parts of dioxane and 2.79 parts (3wt%, based -
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~6~ OoZO 31,996
on o~boric acidj of dimethyldodecylamine; subsequently, 432 parts
(6 moles) Or 2,3-butylene oxide is pressured in in portions at
from 120 to 140Co `~
Pressuring time: 8 hours
Pressure: 8 atmospheres gauge
Temperature: 138C
Stirring tîme: 3 hours ~ ~
Rate o~ conversion, based on oxide consumption: 1:2,35,~3~ "
After removal of residual epoxide and the mixture of dioxane ,;
and water of reaction, and after high vacuum distillation, 3 frac- ~ -
tions are obtained as pale yellow to colorless liquids:
Fraction I: bop~ (0~4 mm) 70C (37 g~; nD: 1.4324; ~20 = 135 cP
(133.5 cSt)
Fraction II: bop~ (004 mm) 90C (22 g); n20: 1.4330, ~20 = 140 cP `~
(139.5 cSt) ~,`
Fraction III: b.p. (o.ll mm) 146C (95 g); n20: 1.4330; ~20 = 145 cP ;~
(143.5 cSt)
89 g o~ a resinous residue
EXAMPLE 6 ;i ~
o-boric acid/isobutylene oxide ~ -
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In a V2A stirred autoclave are placed 124 parts (2 moles)
of o-boric acid, 62 parts of dioxane, and 3.72 parts (3wt%, based
on o-boric acid) of sodium methylate; subsequently, 504 parts ~-
(7 moles) of isobutylene oxide is pressured in in portions at
; from 140 to 150Co
Pressuring time: 9 hours -
Pressure: 8 atmospheres gauge `
Stirring time: 3 hours
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9 0,Z~ 31,996
~ After removal of the residual epoxide and the mixture of
'~ dioxane and water of reaction at subatmospheric pressure, there
is obtained 290 parts of a yellow oil
Rate of conversion, based on oxide consumption: 1:1015 ;~
Boiling point(003 mm): 105C
~20 = 5204 cP (= 51 cSk) r
D20 : 1.028
pH : 4.5
EXAMPLE 7 ;~
o-boric acid/styrene oxide
In a 2 liter V2A stirred autoclave are introduced 62 parts
~10 (1 mole) of o-boric acid, 62 parts of dioxane, 1086 parts (3wt%,
`~` based on o-boric acid) of dimethyldodecylamine, and 360 parts
:, :
(3 moles) of styrene oxide; the contents are slowly heated, and
~`! stirred for 6 hours at 150C under a nitrogen blanket.
After removal of the dioxane in vacuo, there is obtained
`1 350 parts of a red-brown, viscous, water~insoluble product.
~j Rate of conversion~ based on oxide consumption: 1:2.4 ;~
EXAMPLE 8 ~
~, . ' :: .
~- To prepare an oil-type wood preservative containing 7.5% `
of boric acid/propylene oxide product, 7.5 parts of the latter
product (Example 4) is mixed with 13.7 parts of an alkyd resin ` `
~20 of medium oil content r20% solid resin3. There is then added ~ -
. 1 ,. ~ . .
,l 47~3 parts of an aromatics-containing benzene fraction, the ~;
mixture i3 if desired filtered to remove impurities, and is then
made up to 100 parts with a benzene fraction containing aliphatic '~
compounds. ~`
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O~Z. 31,996
EXAMPLE 9 .
An oil-type wood preservative containing 15.1% of active ~` -
ingredient is prepared in similar manner, except that only ~:
3917 parts of the aromatics-containing benzene fraction is used ` : ~ .
,....... .
instead of 47.3 parts
EXAMPLE 10 `: :
To determine the effectiveness of the preservatives of the
invention on wood-destroying fungi, pine sapwood and beechwood
2 ` !
blocks 50x25x15 mm in size were coated with 200 g/m of wood sur- : :
face Or the oil-type wood preservative formulations of Examples
8 and 9. After 4 weeks' storage the treated blocks were placed, i.;~ .:
together with untreated controls, in glass dishes containing3 .:. ~ .in a nutrient medium, the test fungi Coniophora cerebella and
Polystictus (Coriolus) versicolorO The dishes were then incubated
under controlled conditions (22C; 70% relative humidity). ::
, . . .
After four months the mycelium adhering to the blocks ~ : :
was removed and the blocks were dried. The weight loss and :
degree of wood destruction wère then ascertainedD ~;
,
Amount of Coniophora cerebella Polystictus versicolor
boric acid/ (pinewood) (beechwood)
propylene oxide weight degree of weight degree of :~
product in ~or- loss in destruction loss in destruction . ~.:
mulation in % % %
7.5 0 1 2 2a ~:
15.1 0 1 0
Control . ~
(untreated) 21 3b/4a 18 3b
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O.Z. ~1,996
Scale
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1 = undamaged -~
2a - slight attack in parts
2b = slight attack overall ~,
3a = marked attack in parts
3b = marked attack overall
4a = completely destroyed ln parts
4b = completely destroyed overall
EXAMPLE 11
The boric acid/propylene oxide product was added as preserv- ~`
ative to an aqueous wood glue mixture based on a urea/formaldehyde
polycondensate. Beech and spruce chips were glued with these binder ;
mixtures, 9 parts of resin (dry weight) being used for 100 parts
of chips~ The chips coated with binder were pressed for 6 minutes
at a temperature of 165C to give 18 mm thick chipboard. The amount
of preservative was such that the finished boards contained 7.5%
of the boric acid/propylene oxide product, based on dry chips.
For comparison purposes, chipboard was produced to which boric ~
I0 acid in powder form had been admixed in amounts of 2%, based on ~ '
::~
dry chips, after the chips had been glued. The amount of 2% boric ,~ -
acid corresponds to the boric acid content of the 705% boric acid
propylene oxide product obtained in accordance with Example 4. .,~
Specimens 50x25x18 mm in size were cut from the chipboard
and examined as to their resistance to attack by the wood-de~
stroying fungi Coniophora cerebella and Polystictus versi_ol_r and
by the mold fungi A~pergillus niger and Trichoderma viride. The
specimens were placed on biomalt nutrient agar glass plates covered
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oOzO 31~996
with the wood-destroying fungi, and incubated at 22C. After
16 weeks the extent oP fungus spread on the specimens was
..~,,,
assessedO The experiments with the mold fungi were carried out ~ :
analogously, however, the duration was only 14 days here, as :
the untreated specimens were completely covered with fungus `~
after this length o~ time.
Specimen; Extent of fungus spread on wood after 16 weeks
fungicide added Coniophora cerebella Polystictus versicolor `~:
7.5% boric acid/ : - `
propylene oxide 0 0
2% boric acid ::
(comparative agent) 2
none (untreated) 3 3
Specimen; Extent of fungus spread after 14 days . :
fungicide added Aspergillus niger Trichoderma viride .
.. . - . ........ _ . : : .
7.5% boric acid/
propylene oxide 0 0 ~` :
2% boric acid .
(comparative agent) 1 2 ..
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none (untreated) 3 3 ~ - .
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0 no fungus on specimen .;~
1 sides of specimen covered with fungus
2 specimen covered to a considerable extent with fungus ~ .
3 specimen completely covered with fungus
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