My appologies, I missed the 'a' in the benzal chloride, and thought you said benzyl chloride.  That method works for benzal chloride (chlorine + toluene) however, hydrolysis does not go as well as it should.  There is a thread on SM where one of the higher members attempted hydrolysis of benzal chloride with a base (I believe it was klute) and the reaction was quite low yielding. 

Reference Information



Kinetics of the Nitric Acid Oxidation of Benzyl Ethers to Benzaldehydes
Yoshiro Ogata, Yasuhiko Sawaki
J. Am. Chem. Soc. 1966, 88 (24), pp 5832–5837


Abstract
The nitric acid oxidation of benzyl ethers has been studied kinetically in aqueous dioxane. The
oxidation is initiated by a small amount of nitrous acid and follows first-order kinetics with respect to the ether.
The rate of oxidation is in most cases independent of either nitric acid (over 0.5 M) or nitrous acid, while the oxidation
with more dilute (below 0.5 M) nitric acid contains a term of nitric acid in the rate equation. The oxidation is
accelerated by increasing the acidity of media; the plot of log kl cs. -Ha gives a straight line with a slope of 1.0.
The rate constant also increases with increasing dioxane content in the solvent. The apparent energy and entropy of
activation are 31-34 kcal/mole and 10-13 eu, respectively. The substituent effect in the benzyl ring satisfies Hammett's
equation, giving a p value of - 1.9. A polar effect is also observed with the substituents in alkyl group, the
order of reactivity being i-Pr > Et > Me > CsHs. A mechanism which involves the benzyl hydrogen abstraction
by the conjugate acid of nitrogen dioxide is postulated and discussed.


--------------------------------------


Kinetics of Oxidation of Benzyl Alcohol with Dilute Nitric Acid
Sudhir R. Joshi, Kamal L. Kataria, Sudhirprakash B. Sawant,* and Jyeshtharaj B. Joshi
Ind. Eng. Chem. Res. 2004, 44 (2), pp 325–333


Abstract
The oxidation of benzyl alcohol by dilute nitric acid has been selected for the study as a typical method for the manufacture of industrially important intermediate benzaldehyde. All the reactions have been performed in the absence of any solvent. A catalytic amount of sodium nitrite is essential for the generation of active state of nitrogen. Benzyl nitrite is formed in a substantial amount as an intermediate. The effects of various parameters such as the NaNO2 loading, nitric acid concentration, temperature, and molar ratio have been investigated. The stoichiometric requirement of nitric acid for benzyl alcohol conversion has also been determined. The probable mechanism for the oxidation of benzyl alcohol using nitric acid is proposed, showing the reversible formation of benzyl nitrite and its irreversible decomposition to benzaldehyde. The mass-transfer resistance has been eliminated for the investigation of kinetics of all the reactions in the consecutive path. The influence of chloro substitution on the oxidation rates of 2-chlorobenzyl, 4-chlorobenzyl, and 2,4-dichlorobenzyl alcohols has been presented.

Do you have any refs.? Are you saying that if instead of using styrene I use half the molar ammount of piperine in for example DCM or ether, I'll get Piperonal?

"styrene + oxone"

Yes, this would be really interesting to see happen...

Electrolysis of H2SO4 and H2O prodocue O3 in a decent amount from what I hear.. even if the yeild sucks... the reacts being acid water and electricity are cheap so it would be well work it.. also it would be easier to deal with then would arcs and crazy things...

I use Benzyl Acetate, a very common fragrance ingredient.

Benzyl Acetate to Benzyl Alcohol;
Trans Esterification (i do it because i need Methyl Acetate)
1. dissolve 40 g KOH in 1 l MeOH (above 95%)
2. combine that solution with 1 l Benzyl Acetate in 6 l plastic bottle
3. add some baked K2SO4 or K2CO3 into that bottle, and shake hard to dry it.
4. Filter into 2 l Erlenmeyer flask
5. distillation set up, heat at +- 45 c for 2 hrs, then rise temperature to distill Methyl Acetate-MeOH azeotrope
6. when i got 750 ml in receiving flask i add 500 ml anhydrous MeOH, just optional, distill again till total 1,25 l in receiving flask.
7.  acid hydrolysis to ensure fully conversion, by add 200 ml water (check pH, add KOH if pH below 14), boil for 2 hrs, still in distillation set up. The solution is still homogen (just a little foggy when its cool) means stirring is not necessary,  because most Acetic acid has been converted to Methyl Acetate and distilled that makes just a little Potassium acetate formed during acid hydrolysis.
8. let cool, no smell of benzyl acetate at all when i opened the cap. Neutralize with H3PO4 or whatever, solution will be separated into 2 layers, collect Benzyl Alcohol layer (upper layer) transfer into 1 l beaker glass, and heat to remove remaining water and MeOH. Yield is very good, about 700 ml in my beaker glass, and I'm lazy to count how much precisely. I get 2 benefits from this procedure, Methyl Acetate and the volume can be compressed, just need 2 l beaker glass for 1 l Benzyl Acetate.

 I'll use NaOCl to oxidize it to PhCHO, i'm thinking how to perform it, i'll post the write up if i find something interesting.

As we all know benzyl chloride is easily prepared from gassing toluene with Chlorine gas(light as the catalyst): http://www.faizkaskar.8k.com/light.html

According to wikipedia: "Benzyl alcohol is prepared by the hydrolysis of benzyl chloride using sodium hydroxide:
C6H5CH2Cl + NaOH ? C6H5CH2OH + NaCl"

From Benzyl alcohol I found a very interesting paper: http://docs.google.com/viewer?a=v&q=cache:2G7Q5LGwXMEJ:www.desline.com/articoli/7547.pdf+benzyl+alcohol+oxidation&hl=en&gl=us&pid=bl&srcid=ADGEESh1jOBF1_WjpqcsL_ng9QASvoNvcnOvQvMq4Sp009CUdbv7lyhpniXmd-uLy0jYVw3xGBsbwAYPcB7RO6pjMNdlfO8b7SpPyiLGnNuLz8KuZxFd5NMmOfLjUiabdogaF5CEdyGz&sig=AHIEtbT6fL3RTOt8U-5SeDxupDRLVZs2XA

The paper details photo-oxidation of benzyl alcohol to benzaldehyde utilizing TiO2 as the catalyst.  The experiment is interesting because they essentially let the sun do all the work.  Essentially setting the benzyl alcohol vat with TiO2 in the sun for a day yielded benzaldehyde.  This would of course be nice because of its painless scalability.

I'd be curious to determine which light wavelengths are responsible for the reaction.  I read that chlorine is best effected by blue light for reaction and removal, and that correlates with the wavelengths chlorine absorbs, so I would assume that if this is true for other reactions, ideal lighting could be calculated for additions and elimination reactions.